WO2025021960A1

WO2025021960A1 - Biosensors for measuring glucose concentration and glucose-sensing polymers

Info

Publication number: WO2025021960A1
Application number: PCT/EP2024/071215
Authority: WO
Inventors: Oliver CREESE; Zygimantas GRICIUS; Lukas SCHERER
Original assignee: GLUCOSET
Current assignee: GLUCOSET
Priority date: 2023-07-25
Filing date: 2024-07-25
Publication date: 2025-01-30
Anticipated expiration: 2026-01-25

Abstract

The present invention relates to a biosensor for measuring the concentration of glucose and its use in glucose sensing. The biosensor of the present invention comprises a polymer comprising a boronic acid-based glucose-binding moiety, wherein said boronic acid-based glucose-binding moiety is immobilized in said polymer, and an inhibitor moiety, wherein said inhibitor moiety is immobilized in said polymer, and wherein said inhibitor moiety is capable of forming reversible crosslinks by binding to said boronic acid-based glucose-binding moiety. In the absence of glucose, the polymer is crosslinked by a bond formed between the boronic acid-based glucose-binding moiety and the inhibitor moiety. In the presence of glucose, the boronic acid-based glucose-binding moiety binds to glucose, whereby the bond between the boronic acid-based glucose-binding moiety and the inhibitor moiety is broken, which results in a change of volume of the polymer. The biosensor of the present invention is particularly useful for glucose monitoring performed on a subject under intensive care as well as in the situations wherein the glucose monitoring is performed on an unconscious subject.

Description

Biosensors for measuring glucose concentration and glucose-sensing polymers

The present application claims the benefit of priority of European patent application EP 23 187 706.9, filed on July 25, 2023, which is incorporated herein by reference in its entirety.

The present invention relates to a biosensor for measuring the concentration of glucose and its use in glucose sensing. The biosensor of the present invention comprises a polymer (in particular a polymeric hydrogel) comprising a boronic acid-based glucose-binding moiety, wherein said boronic acid-based glucose-binding moiety is immobilized in said polymer; and an inhibitor moiety, wherein said inhibitor moiety is immobilized in said polymer, and wherein said inhibitor moiety is capable of forming reversible crosslinks by binding to said boronic acid-based glucose-binding moiety, wherein in the absence of glucose, the polymer is crosslinked by a bond formed between the boronic acid-based glucose-binding moiety and the inhibitor moiety; and wherein in the presence of glucose, the boronic acid-based glucose-binding moiety binds to glucose, whereby the bond between the boronic acid-based glucose-binding moiety and the inhibitor moiety is broken, which results in a change of volume of the polymer. The biosensor of the present invention is particularly useful for glucose monitoring performed on a subject under intensive care as well as in situations wherein the glucose monitoring is performed on an unconscious subject.

The present invention relates to the development of glucose sensors based on the measurement of osmotic pressure incorporating a boronic acid glucose binding moiety (GBM) and an inhibitor moiety which are covalently bound to the same hydrogel network to yield a glucose responsive material with exceptional sensing properties. The inhibitor strength and choice of inhibitor molar ratio with respect to the GBM are crucial in achieving these highly advantageous sensor properties, namely increased sensitivity, increased linearity and response time, and decreased pH interference.

In addition to glucose sensing applications, polymers capable of delivering active agents in a glucose concentrationdependent manner are sought after, in particular for the treatment of conditions characterized by pathological glucose concentration. For example, diabetes mellitus is a disorder of glucose regulation, characterized by an accumulating glucose concentration in the blood. The breakdown of glucose regulation can be attributed to the inability of the endocrine pancreas to secrete insulin or to the body's inability to properly use insulin. In the case of type 1 diabetes, the usual treatment consists in multiple daily blood glucose controls and subcutaneous insulin injections. However, a better control of glycemia could be achieved if the insulin dose could be continuously adapted to the level of glucose in the blood, therefore avoiding glucose levels below or above the normal range, which causes detrimental complications. In this context, closed-loop delivery of insulin is highly sought-after. This can accordingly be achieved by using a glucose concentration sensing polymeric release system carrying insulin.

Optical glucose sensors utilising a fluorescent boronic acid reporter molecule have been successfully demonstrated clinically (Crane et al. DOI: 10.1177/1932296815587937, Strasma et al. DOI: 10.1177/1932296815585872) and are commercially available (Mortellaro et al. doi.org/10.1016/j.bios.2014.05.022).

Optical boronic acid glucose sensors based on hydrogel volume change have been demonstrated in vivo and in vitro but are not commercially available (Skjaervold et al. Anesthesiology 2011; 114:120-5, Worsley et al. J Diabetes Sci Technol Vol 2, Issue 2, March 2008).

Zhang et al. (DOI: 10.1002/adma.201401710) discloses linear and fast (polyacrylamide PCCA-based) hydrogel glucose sensor materials enabled by a volume resetting agent. Said material comprises a glucose binding moiety (GBM) as well as a linear poly(vinyl alcohol) polymer which acts as an inhibitor to the GBM. However, Zhang et al. does not teach any glucose sensor materials in which a GBM and an inhibitor moiety would be bound to the same polymer.

Figureiredo et al (DOI: 10.1039/d0sm00178c) discloses a hydrogel material obtained by mixing of hyaluronic acid polymer functionalized with an arylboronic acid together with a hyaluronic acid polymer functionalized with a saccharide unit, e.g., a fructose or mannose derivative.

US 9,549,987 discloses certain glucose-responsive hydrogels containing phenylboronic acid (PBA)-grafted hyaluronic acid.

Miyata et al. (DOI: 10.1002/MACP.1996.021970330) teaches a glucose-sensitive hydrogel prepared by introducing concanavalin A into poly(2-glucosyloxyethyl methacrylate) hydrogel. The so obtained hydrogel swells in the presence of glucose in a concentration-dependent manner, and is selective with respect to different saccharides. The document teaches that the swelling properties of this hydrogel might be useful for the development of a glucosesensitive device.

WO 2001/016575 discloses a biosensor having a hydrogel including an immobilized GBM, such as concavalin A, and an immobilized hexose saccharide, such as a-D-mannopyranoside. It is disclosed that free glucose binds competitively with the immobilized hexose to the GBM, thereby reducing the number of hydrogel crosslinks and causing the hydrogel to swell. This document does not teach any boronic acid-based GBMs as required in the present invention.

US 2003/100822 discloses a glucose biosensor comprising a polymer comprising a phenylboronic acid and a glucose moiety, acting as an inhibitor. However, the use of glucose sensors based on polymers comprising both a glucose-binding moiety (GBM) and an inhibitor moiety predicating on the phenomenon of interaction with glucose that changes the volumetric properties of the polymer can be limited due to limited sensitivity of such measurements. Furthermore, due to pKa of boronic acids usually falling within the range of 7-9, such polymeric sensors have been shown to be heavily dependent on the pH (Skjaervold et al ANESTHESIOLOGY 2011 ; 114:18-20, Worsley et al. J Diabetes Sci Technol Vol 2, Issue 2, March 2008, Strasma et al. DOI: 10.1177/1932296815585872). While benzoxaboroles (BOB) are a class of boronic acid with a lower pKa than traditionally used phenyl boronic acid (PBA) allowing for efficient glucose binding at physiological conditions (Dowlut et al. 10.1021/ja057798c), a large pH dependence for BOB sensors was observed in-house, which indicated a universal problem that needed to be addressed. pH sensitivity limits a glucose sensors application, in particular in the context of patients undergoing intensive care. Finally, the complex dependence of volumetric properties on the glucose concentration, in particular its limited sensitivity, linearity, and response time limit the possibilities of accurate determination of the glucose concentration.

The present invention addresses the problem of providing a glucose biosensor with improved properties. Accordingly, the present invention overcomes the above-discussed shortcomings of the prior art and provides a biosensor with improved properties with regard to sensitivity, pH dependence (in the case of BOB), improved linearity of the measurements, and/or reduced response time (in the case of BIS1 ). The ability to tune the sensor, in particular by affecting its sensitivity and linearity, greatly benefits the possibilities to accurately measure glucose concentration. The problem is thus solved by the embodiments disclosed herein and as characterized by the claims.

The invention will be summarized in the following embodiments.

In a first embodiment, the present invention relates to a biosensor for measuring the concentration of glucose, the biosensor comprising a polymer comprising: a boronic acid-based glucose-binding moiety, wherein said boronic acid-based glucose-binding moiety is immobilized in said polymer; and an inhibitor moiety, wherein said inhibitor moiety is immobilized in said polymer, wherein said inhibitor moiety is capable of forming reversible crosslinks by binding to said boronic acid-based glucose-binding moiety; wherein in the absence of glucose, the polymer is crosslinked by a bond formed between the boronic acid-based glucose-binding moiety and the inhibitor moiety; and wherein in the presence of glucose, the boronic acid-based glucose-binding moiety binds to glucose, whereby the bond between the boronic acid-based glucose-binding moiety and the inhibitor moiety is broken, which results in a change of volume of the polymer.

In this first embodiment, it is preferred that the affinity of the inhibitor moiety to the boronic acid-based glucose- binding moiety is in the range of 0.4-fold to 20-fold affinity of said boronic acid-based glucose-binding moiety to glucose. In a second embodiment, the present invention relates to the polymer comprised in the biosensor of the first embodiment, as described herein above.

In a third embodiment, the present invention relates to a biosensor for measuring the concentration of glucose, as described in the first embodiment of the present invention, for use in an in vivo diagnostic method.

In a fourth embodiment, the present invention relates to a biosensor for measuring the concentration of glucose, as described in the first embodiment of the present invention, for use in an in vivo method of glucose monitoring.

In a fifth embodiment, the present invention relates to a biosensor for measuring the concentration of glucose, as described in the first embodiment of the present invention, for use in an in vivo method of diagnosing hyperglycemia or hypoglycemia.

In a sixth embodiment, the present invention relates to use of the biosensor of the first embodiment of the present invention in an in vitro diagnostic method.

In a seventh embodiment, the present invention relates to use of the biosensor of the first embodiment of the present invention for measuring the glucose concentration in a sample.

In an eighth embodiment, the present invention relates to use of the biosensor of the first embodiment of the present invention in an in vitro method of diagnosing hyperglycemia or hypoglycemia.

In a ninth embodiment, the present invention relates to use of the polymer as described in the second embodiment of the present invention for the manufacture of a reagent or a biosensor for monitoring the glucose level in a subject.

In a tenth embodiment, the present invention relates to a glucose-concentration-sensitive release formulation comprising a polymer as described in the second embodiment.

In an eleventh embodiment, the present invention relates to the biosensor of the present invention or to the glucose concentration-sensitive release formulation for use in the treatment of a condition dependent of the glucose concentration (e.g., diabetes).

The invention is further illustrated by the appended figures, which however are not to be construed as limiting.

Fig. 1 presents examples of acrylamide monomers comprising preferred boronic acid-based GBMs.

Fig. 2 shows exemplary monomers comprising inhibitor moieties that have been used in Example 1. Fig. 3 shows an example of glucose sensitive dynamic crosslink in polymer hydrogel.

Fig. 4 depicts swelling degree (sensitivity) of BOB (A) and BIS1 (B) sensors with various inhibitors. Impact of different inhibitor ratios on swelling with BIS1 is shown in panel (C).

Fig. 5 shows impact of inhibitors on the linearity and response time of BIS1 sensors. Linearity is taken as the ratio between the sensor values at the ref. glucose concentrations over the ratio of the ref. glucose concentrations wherein perfect linearity = 1.0.

Fig. 6 presents raw data for BIS1 sensors with increasing ratio of TRIS inhibitor demonstrating the impact on linearity and response time.

Fig. 7 depicts sensor response curves to increasing levels of glucose (PBS, pH 7.4, 37 °C) in the case of BIS1 :TRIS system and BOB:MAN system.

Fig. 8 shows raw plots of BOB-MANPEG2 sensors in PBS, 37°C with 2.2 mM glucose at pH 7.4, pH 6.9 and pH 7.6.

Fig. 9 depicts hydrogel length change with 20 mM glucose (sensitivity), expressed as relative to a hydrogel comprising a boronic acid-based glucose-binding moiety BOB only, without inhibitor moiety, for different inhibitors and increasing inhibitor mol %.

Fig. 10 presents hydrogel length change on moving from pH 7.4 to 6.9 (top panel) and pH 7.4 to 7.6 (bottom panel) for BOB sensors with different inhibitors and increasing inhibitor mol %.

Fig. 11 shows linearity of BOB sensors with different inhibitors and increasing inhibitor mol %. Linearity is taken as the ratio between the sensor values at the ref. glucose concentrations over the ratio of the ref. glucose concentrations, perfect linearity = 1.0.

Fig. 12 depicts hydrogel length change with 20 mM glucose (sensitivity), expressed as relative to a hydrogel comprising a boronic acid-based glucose-binding moiety BOB only, without inhibitor moiety, for BOB sensors with MAN inhibitor with different linker length (q) and increasing inhibitor mol%.

Fig. 13 shows hydrogel length change on moving from pH 7.4 to 6.9 for BOB sensors with MAN inhibitor with different linker length (q) and increasing inhibitor mol%. Fig. 14 presents hydrogel length change on moving from pH 7.4 to 7.6 for BOB sensors with MAN inhibitor with different linker length (q) and increasing inhibitor mol%.

Fig. 15 presents calculated K_eq values for model diols.

Fig. 16 shows in part 1 combined titration curves used to determine K_eq of BOB with various diols, carried out in 0.1 M phosphate buffer pH 7.4 at room temperature, in part 2 titration curves of ARS against BOB, used to determine K_eq of BOB with various diols, carried out in 0.1 M phosphate buffer pH 7.4 at room temperature (RT).

Fig. 17 shows (A) a Model of the Fabry-Perot interferometer. The hydrogel makes up the Fabry-Perot cavity. The refractive indexes n_eff, n_g, nt are the effective index of the fiber, index of the hydrogel and index of the fluid, respectively. The spacing of the two boundaries is indicated as L_g, also referred to as the hydrogel length; (B) a typical interference pattern from a low finesse Fabry-Perot cavity. The wavelength of the light is converted to frequency on the x-axis. The observed 0.35 phase shift is equivalent to a hydrogel cavity length change of 100 nm.

Fig. 18 shows ¹H NMR spectrum (upper) and ¹³C DEPT spectrum (lower) for MANPEGS (2-[2-[2-[2-(2- Acryloylamidoethoxy)-ethoxy]ethoxy]ethoxy]ethoxy]ethyl-alpha-D-mannopyranoside).

Fig. 19 shows ¹H NMR spectrum (upper) and ¹³C DEPT spectrum (lower) for MANPEG2 (2-[2-(2- Acryloylamidoethoxy)ethoxy]ethyl-alpha-D-mannopyranoside).

Fig. 20 shows ¹H NMR for compound 1 (upper) and its bis-boronic acid analogue (lower) in the synthesis of BIS1 .

Fig. 21 shows in part 1 ¹H NMR (upper) and ¹³C NMR spectra, and in part 2 ¹H-¹H COSY (upper) and ¹H-¹H HSQC (lower spectra) ¹H NMR for the final FUR compound.

Fig. 22 shows ¹H NMR for compound BIS3.

Fig. 23 shows sensitivity for BOB-MANPEG5 sensors (1 : 1) with different backbones (upper) and raw traces for BOB- MANPEG5 sensors (1 : 1) with different backbones at increasing concentrations of glucose in PBS pH 7.4, 37 °C (lower).

As mentioned before, the present invention relates to a biosensor for measuring the concentration of glucose, the biosensor comprising a polymer comprising:

• a boronic acid-based glucose-binding moiety, wherein said boronic acid-based glucose-binding moiety is immobilized in said polymer; and

• an inhibitor moiety, wherein said inhibitor moiety is immobilized in said polymer, and wherein said inhibitor moiety is capable of forming reversible crosslinks by binding to said boronic acid-based glucose-binding moiety; wherein in the absence of glucose, the polymer is crosslinked by a bond formed between the boronic acid-based glucose-binding moiety and the inhibitor moiety; and wherein in the presence of glucose, the boronic acid-based glucose-binding moiety binds to glucose, whereby the bond between the boronic acid-based glucose-binding moiety and the inhibitor moiety is broken, which results in a change of volume of the polymer.

The biosensor of the present invention is highly advantageous as it shows improved sensitivity to changes in glucose concentration, improved linearity in response to glucose concentration, improved response time (in the case of BIS1 sensors) and improved pH tolerance (in the case of BOB sensors) when compared to the biosensor in question lacking the inhibitor moiety.

In particular, the present invention is based, at least in part, on the surprising finding that improved sensitivity to changes in glucose concentration, improved linearity in response to glucose concentration and improved pH tolerance can be achieved by selecting the inhibitor moiety and the boronic acid-based glucose-binding moiety in such a manner that their binding affinity falls within a specific range, namely in the range corresponding to 0.4-fold to 20-fold the binding affinity between the respective boronic acid-based glucose-binding moiety and glucose. It is thus preferred that the affinity of the inhibitor moiety to the boronic acid-based glucose-binding moiety is in the range of 0.4-fold to 20-fold affinity of said boronic acid-based glucose-binding moiety to glucose. In other words, it is preferred that the affinity of the inhibitor moiety to the boronic acid-based glucose-binding moiety is 0.4-fold to 20-fold as high as the affinity of the boronic acid-based glucose-binding moiety to glucose.

More preferably, the affinity of the inhibitor moiety to the boronic acid-based glucose-binding moiety is in the range of 1.2-fold to 20-fold affinity of said boronic acid-based glucose-binding moiety to glucose. Even more preferably, the affinity of the inhibitor moiety to the boronic acid-based glucose-binding moiety is in the range of 2-fold to 10- fold affinity of said boronic acid-based glucose-binding moiety to glucose. Accordingly, it is particularly preferred that the affinity of the inhibitor moiety to the boronic acid-based glucose-binding moiety is 2-fold to 10-fold as high as the affinity of the boronic acid-based glucose-binding moiety to glucose.

The affinity of the inhibitor moiety to the boronic acid-based glucose-binding moiety can be measured according to any method known in the art, for example by using NMR titration, isothermal titration calorimetry, or a fluorescencebased method. It is to be understood that the affinity should be measured when both the boronic acid-based glucose-binding moiety and the inhibitor moiety are immobilized in the polymer. For practical reasons, however, the aforementioned affinity of the inhibitor moiety to the boronic acid-based glucose-binding moiety can also be determined (i) by measuring the affinity of a compound comprising said inhibitor moiety (which can be provided in solution) to the boronic acid-based glucose-binding moiety (which is immobilized in the polymer), or (ii) by measuring the affinity of a compound comprising the boronic acid-based glucose-binding moiety (which can be provided in solution) to the inhibitor moiety (which is immobilized in the polymer), or (ill) by measuring the affinity of a compound comprising the inhibitor moiety to a compound comprising the boronic acid-based glucose-binding moiety. Among these possibilities, option (i) is preferred, i.e., that the affinity of a compound comprising the inhibitor moiety to the boronic acid-based glucose-binding moiety is measured. It is furthermore preferred that the compound comprising the inhibitor moiety is composed of the inhibitor moiety and the chemical moiety which is responsible for attachment of the inhibitor moiety to the polymer; for example, if the inhibitor moiety (immobilized in the polymer) is glucose which is attached through a glycosidic bond to the polymer, e.g., as shown herein below:

wherein -R- is a methylene (-CH2-), then the following compound (comprising the inhibitor moiety and the chemical moiety responsible for attachment to the polymer, i.e., the methylene moiety) may be used for affinity measurements:

The polymer as provided in accordance with the present invention is not particularly limited. It is preferred that the polymer is hydrophilic, which is beneficial when the polymer is brought into contact with the blood of a subject. Preferably, the polymer forms a polymeric hydrogel, i.e., the polymer is preferably a polymeric hydrogel. A hydrogel is generally understood to be a biphasic material comprising a solid polymer, which preferably forms a porous and permeable structure, and an interstitial fluid comprised within and in contact with said solid polymer. In a hydrogel, said fluid is preferably water or an aqueous solution (e.g., a liquid composition comprising at least 90% (v/v) water). It will be understood that the polymeric hydrogel typically includes crosslinks between the individual polymer molecules forming the hydrogel. Such crosslinks may be covalent or non-covalent (which in turn may also be dynamic, i.e., may be subject to forming and unforming, as described in the following).

The term polymer preferably also encompasses dendrimers and non-crosslinked polymers.

Preferred examples of the polymer (or the polymeric hydrogel) to be used in the biosensor of the present invention are described herein below. In general, it is preferred that the polymer does not comprise hyaluronic acid. It is accordingly preferred that the polymeric hydrogel comprised in the biosensor of the present invention does not comprise hyaluronic acid.

Preferably, the polymer of the present invention is a polyacrylamide-based polymer. The term "polyacrylamidebased polymer” preferably refers to a polymer made from (or composed of) more than 50% (w/w) of acrylamide monomers, more preferably at least 60% (w/w) of acrylamide monomers, even more preferably at least 70% (w/w) of acrylamide monomers, even more preferably at least 80% (w/w) of acrylamide monomers, or yet even more preferably at least 90% (w/w) of acrylamide monomers. Accordingly, the polyacrylamide-based polymer is preferably obtainable by polymerization of a composition of monomers wherein more than 50% (w/w) (or, with increasing preference, at least 60% (w/w), at least 70% (w/w), at least 80% (w/w), or at least 90% (w/w)) of the monomers are acrylamide monomers.

It will be understood that "acrylamide monomers” are compounds comprising an acrylamide moiety, e.g., as illustrated in the following:

Such acrylamide monomers may also be referred to as N-substituted acrylamide monomers.

In principle, further substitutions may be made to the alkenyl moiety in the above-depicted acrylamide monomer, but it is preferred that the alkenyl moiety is unsubstituted. Accordingly, reference can be made to unsubstituted polyacrylamide-based polymer, which preferably refers to a polymer made from (or composed of) more than 50% (w/w) of acrylamide monomers, wherein the alkenyl moiety is unsubstituted, more preferably at least 60% (w/w) of acrylamide monomers, wherein the alkenyl moiety is unsubstituted, even more preferably at least 70% (w/w) of acrylamide monomers, wherein the alkenyl moiety is unsubstituted, even more preferably at least 80% (w/w) of acrylamide monomers, wherein the alkenyl moiety is unsubstituted, or yet even more preferably at least 90% (w/w) of acrylamide monomers wherein the alkenyl moiety is unsubstituted. Accordingly, the unsubstituted polyacrylamide-based polymer is preferably obtainable by polymerization of a composition of monomers wherein more than 50% (w/w) (or, with increasing preference, at least 60% (w/w), at least 70% (w/w), at least 80% (w/w), or at least 90% (w/w)) of the monomers are acrylamide monomers, wherein the alkenyl moiety is unsubstituted.

The use of acrylamide monomers is advantageous, as these monomers combine the desired hydrophilic properties, which facilitate the formation of a hydrogel, with ease of functionalization, as required when constructing the polymer of the present invention and with increased stability towards hydrolysis compared to acrylate monomers.

The polymer of the present invention may also be a polymethacrylamide-based polymer. The term "polymethacrylamide-based polymer” preferably refers to a polymer made from (or composed of) more than 50% (w/w) of methacrylamide monomers, more preferably at least 60% (w/w) of methacrylamide monomers, even more preferably at least 70% (w/w) of methacrylamide monomers, even more preferably at least 80% (w/w) of methacrylamide monomers, or yet even more preferably at least 90% (w/w) of methacrylamide monomers. Accordingly, the methacrylamide-based polymer is preferably obtainable by polymerization of a composition of monomers wherein more than 50% (w/w) (or, with increasing preference, at least 60% (w/w), at least 70% (w/w), at least 80% (w/w), or at least 90% (w/w)) of the monomers are methacrylamide monomers.

It will be understood that "methacrylamide monomers” are compounds comprising an methacrylamide moiety, e.g., as illustrated in the following:

Such methacrylamide monomers may also be referred to as N-substituted methacrylamide monomers.

The polymer of the present invention may also be a poly aery late-based polymer. The term "polyacrylate-based polymer” preferably refers to a polymer made from (or composed of) more than 50% (w/w) of acrylate monomers, more preferably at least 60% (w/w) of acrylate monomers, even more preferably at least 70% (w/w) of acrylate monomers, even more preferably at least 80% (w/w) of acrylate monomers, or yet even more preferably at least 90% (w/w) of acrylate monomers. Accordingly, the polyacrylate-based polymer is preferably obtainable by polymerization of a composition of monomers wherein more than 50% (w/w) (or, with increasing preference, at least 60% (w/w), at least 70% (w/w), at least 80% (w/w), or at least 90% (w/w)) of the monomers are acrylate monomers.

It will be understood that "acrylate monomers” are compounds comprising an acrylate moiety, e.g., as illustrated in the following:

The polymer of the present invention may also be a polymethacrylate-based polymer. The term "polymethacrylate- based polymer” preferably refers to a polymer made from (or composed of) more than 50% (w/w) of methacrylate monomers, more preferably at least 60% (w/w) of methacrylate monomers, even more preferably at least 70% (w/w) of acrylate monomers, even more preferably at least 80% (w/w) of methacrylate monomers, or yet even more preferably at least 90% (w/w) of methacrylate monomers. Accordingly, the polymethacrylate-based polymer is preferably obtainable by polymerization of a composition of monomers wherein more than 50% (w/w) (or, with increasing preference, at least 60% (w/w), at least 70% (w/w), at least 80% (w/w), or at least 90% (w/w)) of the monomers are methacrylate monomers. It will be understood that "methacrylate monomers” are compounds comprising a methacrylate moiety, e.g., as illustrated in the following:

Preferably, the polymer is an unsubstituted polyacrylamide-based polymer.

As used herein, "measuring the concentration of glucose” may comprise measuring an absolute value of the concentration of glucose in a liquid (e.g., blood) which is contacted with the biosensor. However, the measuring the concentration of glucose also refers to the determination of the concentration of glucose relative to a threshold value. For example, measuring the concentration of glucose may also involve determining whether the concentration of glucose is lower than a threshold value, or higher than a threshold value, or whether said concentration falls within a reference range of concentration. This is particularly useful in clinical settings, e.g., when a dropping of the blood glucose concentration below a certain critical threshold value necessitates an intervention by a physician.

The measurement of the concentration of glucose using the biosensor of the present invention predicates on a change of volume of the polymer upon being contacted with a liquid comprising glucose, in other words, upon being contacted with glucose. Accordingly, when the polymer (or, as in the preferred case, the polymeric hydrogel) is contacted with a liquid comprising no glucose (which may also be referred to as a liquid comprising glucose below a minimum detectable concentration or below a certain threshold value), in other words in the absence of glucose, the polymer (or the polymeric hydrogel) is crosslinked by a bond formed between the boronic acid-based glucose- binding moiety and the inhibitor moiety. In turn, when exposed to a liquid comprising glucose (i.e., comprising a detectable concentration of glucose or comprising glucose at a concentration exceeding a certain threshold value), in other words in the presence of glucose, the boronic acid-based glucose-binding moiety binds to glucose, whereby the bond between the boronic acid-based glucose-binding moiety and the inhibitor moiety is broken, which results in a change of volume of the polymer. The change of volume of the polymer (or polymeric hydrogel) which can be observed upon transition from a liquid comprising no glucose to a liquid comprising glucose, in other words upon transition from the absence of glucose to the presence of glucose, is preferably an increase in volume, i.e. a swelling, of the polymer (or the polymeric hydrogel).

The swelling effect as described herein is not limited to occurring only upon transfer of the biosensor of the invention from conditions of the absence of glucose to conditions of the presence of glucose. Rather, a transfer or change from a first glucose concentration to a second glucose concentration can also result in (and can thus be determined by detecting) a change in volume of the biosensor. Preferably, if the biosensor is transferred to a higher glucose concentration, an increase in volume, i.e. a swelling, of the polymer (or of the polymeric hydrogel) can be detected.

Accordingly, in the measurement of the concentration of glucose, the change in the volume of the polymer or the polymeric hydrogel provides a measure of the concentration of glucose (or the change in the concentration of glucose, as the case may be). The biosensor of the present invention allows an advantageously sensitive determination of the glucose concentration by measuring even very small changes in volume of the polymer and, accordingly, can be implemented, for example in a clinical setting or in an in vitro setting. Thus, the present invention relates to a biosensor for measuring the concentration of glucose, wherein the measurement is based on determining a glucose concentration-sensitive change in the volume of the polymer (or, as preferred in the present invention, of the polymeric hydrogel) comprised in the biosensor.

Moreover, the determination/detection of a change of volume of the polymer can also be effected by measuring another related value, particularly a proxy (or surrogate) value which is dependent on the volume of the polymer, for example, by measuring the osmotic pressure (or a change of the osmotic pressure). Thus, the present invention also relates to a biosensor for measuring the concentration of glucose, wherein the measurement of the concentration of glucose is based on a glucose concentration-sensitive change in the osmotic pressure within the polymer (or, as preferred in the present invention, of the polymeric hydrogel) comprised in the biosensor.

The polymer (polymeric hydrogel) volume change, i.e., swelling/shrinking in response to contact with glucose is reversible and can be measured (and consequently also real time monitored) by various signal-transducing mechanisms, including electrochemical, mechanical, and optical techniques (for example by means of Fabry-Perot- Interferometry or refractometry). The refractive index of the polymer can be changed simply as a result of the volume change (i.e. if the polymer swells it will become more rarefied and so its refractive index will fall) and/or because analyte molecules bind to the polymer chains.

Accordingly, as described herein, the biosensor of the present invention is sensitive to changes in the concentration of glucose. The biosensor of the present invention is thus suitable for measuring or, in other words, sensing, the concentration of glucose. The biosensor allows displaying the concentration of glucose, e.g., in absolute terms or in relative terms (e.g., whether the glucose concentration exceeds or falls below a threshold value, or whether it is within or without a reference concentration range). Yet, the present invention also encompasses embodiments wherein the concentration of glucose (as measured by the biosensor) is not explicitly displayed (e.g., wherein the glucose concentration is not provided to the user of the biosensor as an output), but where a downstream event is triggered by the occurrence of a particular glucose concentration (e.g., by passing above a defined upper-limit threshold concentration of glucose and/or by passing below a defined lower-limit threshold concentration of glucose) as measured by the biosensor. Such an event may, for example, include a glucose-sensitive release of an active substance (or a therapeutic agent), such as, e.g., insulin, into the blood of a subject. A corresponding release can be effected, e.g., by providing a biosensor according to the present invention, wherein an active substance/therapeutic agent (e.g., insulin) is provided (or "stored”) within the polymer, and whereby a swelling of the polymer in the presence of glucose results in a release of the active substance/therapeutic agent from the polymer into the surrounding area (e.g., into the blood of a subject). Various designs for drug-releasing polymers or polymeric drug delivery systems are known in the art and can be used in accordance with the present invention (see, e.g., Liechty WB et al., Polymers for Drug Delivery Systems, Anna Rev Chem Biomol Eng, 2010, 1 : 149-173, DOI: 10.1146/annurev-chembioeng-073009-100847; Sabbagh F et al., From formulation of acrylamide-based hydrogels to their optimization for drug release using response surface methodology, Mater Sci Eng C Mater Biol Appl, 2018, 92:20-25, DOI: 10.1016/j.msec.2018.06.022; or McKenzie M et al., Molecules, 2015, 20(11):20397- 408, DOI: 10.3390/molecules201119705; each of which is incorporated by reference in its entirety). Alternatively, the biosensor of the invention can also be provided in, or can be connected (e.g., physically or electronically) to, a drug delivery device, whereby the biosensor signals the occurrence of a defined glucose concentration (or, e.g., the surpassing of a defined upper-limit threshold concentration of glucose and/or the falling below a defined lower- limit threshold concentration of glucose) to the device which consequently effects the release of an active substance or therapeutic agent (e.g., insulin).

The biosensor thus also encompasses glucose concentration-sensitive medical devices with a therapeutic purpose. In a non-limiting example, the biosensor of the present invention is suitable for the treatment of conditions dependent on blood glucose concentration, for example diabetes. In this case, the biosensor of the invention may include a releasable insulin formulation, wherein said insulin formulation is configured to be released dependent on the measured/sensed concentration of glucose.

Thus, the present invention further relates to a glucose-concentration-sensitive release formulation comprising the polymer as described herein. The invention likewise relates to a glucose-concentration-sensitive release formulation comprising as biosensor as described herein. Specific uses of such glucose-concentration-sensitive release formulations are as described herein.

Preferably, the boronic acid-based glucose-binding moiety comprises a moiety of formula (la) and/or a moiety of formula (lb):

The moieties of formula (la) and formula (lb) may be interconvertible and may be present in an equilibrium, depending on the external conditions, e.g., the surrounding medium. In particular, in an aqueous medium, these moieties may be interconverted by undergoing a ring-closing condensation reaction or a corresponding ring- opening reaction, as illustrated in the following scheme:

Thus, whenever reference is made to one of these forms, it can be expected that both forms will be present in an aqueous environment and will be interconvertible with one other.

It will further be appreciated that the structures (la) and (lb) are capable of existing in a form with a further OFT moiety attached, as structures with an sp³ boron atom, as shown in the following scheme:

In formula (la) and in formula (lb), each R^s is independently selected from C1-5 alkyl, C2-5 alkenyl, C2-5 alkynyl, -(C0-3 alkylene)-OH, -(C0-3 alkylene)-O(Ci-5 alkyl), -(C0-3 alkylene)-O(Ci-5 alkylene)-OH, -(C0-3 alkylene)-O(Ci-5 alkylene)-O(Ci-5 alkyl), -(C0-3 alkylene)-SH, -(C0-3 alkylene)-S(Ci-5 alkyl), -(C0-3 alkylene)-S(Ci-5 alkylene)-SH, -(C0-3 alkylene)-S(Ci-5 alkylene)-S(Ci-5 alkyl), -(C0-3 alkylene)-NH2, -(C0-3 alkylene)-NH(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)(Ci-₅ alkyl), -(C0-3 alkylene)-NH-OH, -(C0-3 alkylene)-N(Ci.₅ alkyl)-OH, -(C0-3 alkylene)-NH-O(Ci.₅ alkyl), -(C0-3 alky lene)-N (C1-5 alkyl)-O(Ci-5 alkyl), -(C0-3 alky lene)-halogen, -(C0-3 alkylene)-(Ci-5 haloalkyl), -(C0-3 alkylene)-O-(Ci-5 haloalkyl), -(C0-3 alkylene)-CN, -(C0-3 alkylene)-NO2, -(C0-3 alkylene)-CHO, -(C0-3 alkylene)-CO-(Ci-5 alkyl), -(C0-3 alkylene)-COOH, -(C0-3 alkylene)-CO-O-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO-(Ci-5 alkyl), -(C0-3 alkylene)-CO-NH2, -(C0-3 alkylene)-CO-NH(Ci-5 alkyl), -(C0-3 alkylene)-CO-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-CO-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-CO-(Ci-5 alkyl), -(C0-3 alkylene)-NH-CO-O-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-CO-O-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO-NH-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO- N(CI-5 alkyl)-(Ci-5 alkyl), -(C0-3 alkylene)-SO2-NH2, -(C0-3 alkylene)-SO2-NH(Ci-5 alkyl), -(C0-3 alkylene)-SO2-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-SO2-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-SC>2-(Ci-5 alkyl), -(C0-3 alkylene)-SC>2-(Ci-5 alkyl), -(C0-3 alkylene)-S0-(Ci-5 alkyl), -(C0-5 alkylene)-carbocyclyl, and -(C0-5 alkylene)-heterocyclyl, wherein one or more -CH2- units in the alkylene moiety in said -(C0-5 alkylene)-carbocyclyl and/or in the alkylene moiety in said -(C0-5 alkylene)-heterocyclyl are each optionally replaced by a group independently selected from -O-, -CO-, -CO-O-, -O-CO-, -NH-, -N(CI-5 alkyl)-, -NH-CO-, -N(CI-5 alkyl)-CO-, -CO-NH-, -CO-N(CI.₅ alkyl)-, -S-, -SO-, -SO₂-, -SO2-NH-, -SO₂-N(CI.₅ alkyl)-, -NH-SO2-, and -N(CI.₅ alkyl)-SO2-, and further wherein the carbocyclyl moiety in said -(C0-5 alkylene)-carbocyclyl and the heterocyclyl moiety in said -(C0-5 alkylene)-heterocyclyl are each optionally substituted with one or more groups independently selected from C1-5 alkyl, C2-5 alkenyl, C2-5 alkynyl, -OH, -O(Ci-5 alkyl), -O(Ci-5 alkylene)-OH, -O(Ci-5 alkylene)-O(Ci-5 alkyl), -SH, -S(Ci.₅ alkyl), -S(Ci.₅ alkylene)-SH, -S(Ci.₅ alkylene)-S(Ci.₅ alkyl), -NH₂, -NH(CI.₅ alkyl), -N(CI.₅ alkyl)(Ci.5 alkyl), -NH-OH, -N(CI.₅ alkyl)-OH, -NH-O(CI.₅ alkyl), -N(CI.₅ alkyl)-O(Ci.₅ alkyl), halogen, C1.5 haloalkyl, -O-(Ci.₅ haloalkyl), -CF₃, -ON, -NO₂, -OHO, -CO-(Ci.₅ alkyl), -COOH, -CO-O-(Ci.₅ alkyl), -O-CO-(Ci.₅ alkyl), -CO-NH2, -CO-NH(CI.5 alkyl), -CO-N(CI.₅ alkyl)(Ci.₅ alkyl), -NH-CO-(CI.₅ alkyl), -N(CI.₅ alkyl)-CO-(Ci.₅ alkyl), -NH-CO-O-(CI.5 alkyl), -N(CI.₅ alkyl)-CO-O-(Ci.₅ alkyl), -O-CO-NH-(CI.₅ alkyl), -O-CO-N(CI.₅ alkyl)-(Ci.₅ alkyl), -SO2-NH2, -SO₂-NH(CI.5 alkyl), -SO₂-N(CI.₅ alkyl)(Ci.₅ alkyl), -NH-SO₂-(CI.₅ alkyl), -N(CI.₅ alkyl)-SO₂-(Ci.₅ alkyl), -SO2-(Ci-5 alkyl), -SO-(Ci-5 alkyl), cycloalkyl, and heterocycloalkyl.

Preferably, each R^s is independently selected from C1-5 alkyl, C2-5 alkenyl, C2-5 alkynyl, -(C0-3 alkylene)-OH, -(C0-3 alkylene)-O(Ci-5 alkyl), -(C0-3 alkylene)-O(Ci-5 alkylene)-OH, -(C0-3 alkylene)-O(Ci-5 alkylene)-O(Ci-5 alkyl), -(C0-3 alkylene)-SH, -(C0-3 alkylene)-S(Ci-5 alkyl), -(C0-3 alkylene)-S(Ci-5 alkylene)-SH, -(C0-3 alkylene)-S(Ci-5 alkylene)-S(Ci-5 alkyl), -(C0-3 alkylene)-NH2, -(C0-3 alkylene)-NH(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)(Ci-5 alkyl), -(Co-3 alkylene)-NH-OH, -(C0-3 alkylene)-N(Ci.₅ alkyl)-OH, -(C0-3 alkylene)-NH-O(Ci.₅ alkyl), -(C0-3 alky lene)-N (C1-5 alkyl)-O(Ci-5 alkyl), -(C0-3 alky lene)-halogen, -(C0-3 alkylene)-(Ci-5 haloalkyl), -(C0-3 alkylene)-O-(Ci-5 haloalkyl), -(C0-3 alkylene)-CN, -(C0-3 alkylene)-NO2, -(C0-3 alkylene)-CHO, -(C0-3 alkylene)-CO-(Ci-5 alkyl), -(C0-3 alkylene)-COOH, -(C0-3 alkylene)-CO-O-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO-(Ci-5 alkyl), -(C0-3 alkylene)-CO-NH2, -(C0-3 alkylene)-CO-NH(Ci-5 alkyl), -(C0-3 alkylene)-CO-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-CO-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-CO-(Ci-5 alkyl), -(C0-3 alkylene)-NH-CO-O-(Ci-5 alkyl), -(Co-3 alkylene)-N(Ci-5 alkyl)-CO-O-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO-NH-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO- N(CI-5 alkyl)-(Ci-5 alkyl), -(C0-3 alkylene)-SO2-NH2, -(C0-3 alkylene)-SO2-NH(Ci-5 alkyl), -(C0-3 alkylene)-SO2-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-SO2-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-SO2-(Ci-5 alkyl), -(C0-3 alkylene)-SO2-(Ci-5 alkyl), -(C0-3 alkylene)-SO-(Ci-5 alkyl), -(C0-5 alkylene)-carbocyclyl, and -(C0-5 alkylene)-heterocyclyl.

More preferably, each R^s is independently selected from C1-5 alkyl, C2-5 alkenyl, C2-5 alkynyl, -(C0-3 alkylene)-OH, -(C0-3 alkylene)-O(Ci-5 alkyl), -(C0-3 alkylene)-O(Ci-5 alkylene)-OH, -(C0-3 alkylene)-O(Ci-5 alkylene)-O(Ci-5 alkyl), -(C0-3 alkylene)-SH, -(C0-3 alkylene)-S(Ci-5 alkyl), -(C0-3 alkylene)-S(Ci-5 alkylene)-SH, -(C0-3 alkylene)-S(Ci-5 alkylene)-S(Ci-5 alkyl), -(C0-3 alkylene)-NH2, -(C0-3 alkylene)-NH(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)(Ci-₅ alkyl), -(C_0.3 alkylene)-NH-OH, -(C_0.3 alkylene)-N(Ci.₅ alkyl)-OH, -(C_0.3 alkylene)-NH-O(Ci.₅ alkyl), -(C_0.3 alky lene)-N (C1-5 alkyl)-0(Ci-5 alkyl), -(Co-₃ alky lene)-halogen, -(Co-₃ alkylene)-(Ci-5 haloalkyl), -(Co-₃ alkylene)-O-(Ci-5 haloalkyl), -(Co-₃ alkylene)-CN, -(Co-₃ alkylene)-NO2, -(Co-₃ alkylene)-CHO, -(Co-₃ alkylene)-CO-(Ci-5 alkyl), -(Co-₃ alkylene)-COOH, -(Co-₃ alkylene)-CO-O-(Ci-5 alkyl), -(Co-₃ alkylene)-O-CO-(Ci-5 alkyl), -(Co-₃ alkylene)-CO-NH2, -(Co-₃ alkylene)-CO-NH(Ci-5 alkyl), -(Co-₃ alkylene)-CO-N(Ci-5 alkyl)(Ci-5 alkyl), -(Co-₃ alkylene)-NH-CO-(Ci-5 alkyl), -(Co-₃ alkylene)-N(Ci-5 alkyl)-CO-(Ci-5 alkyl), -(Co-₃ alkylene)-NH-CO-O-(Ci-5 alkyl), -(Co-₃ alkylene)-N(Ci-5 alkyl)-CO-O-(Ci-5 alkyl), -(Co-₃ alkylene)-O-CO-NH-(Ci-5 alkyl), -(Co-₃ alkylene)-O-CO- N(CI-5 alkyl)-(Ci-5 alkyl), -(Co-₃ alkylene)-SO2-NH2, -(Co-₃ alkylene)-SO2-NH(Ci-5 alkyl), -(Co-₃ alkylene)-SO2-N(Ci-5 alkyl)(Ci-5 alkyl), -(Co-₃ alkylene)-NH-SO2-(Ci-5 alkyl), -(Co-₃ alkylene)-N(Ci-5 alkyl)-SO2-(Ci-5 alkyl), -(Co-₃ alkylene)-SC>2-(Ci-5 alkyl), and -(Co-₃ alkylene)-SO-(Ci-5 alkyl).

Even more preferably, each R^s is independently selected from C1-5 alkyl, C2-5 alkenyl, C2-5 alkynyl, -OH, -O(Ci-5 alkyl), -O(Ci-5 alkylene)-OH, -O(Ci-5 alkylene)-O(Ci-5 alkyl), -SH, -S(Ci-5 alkyl), -S(Ci-5 alkylene)-SH, -S(Ci-5 alkylene)-S(Ci-₅ alkyl), -NH₂, -NH(Ci.₅ alkyl), -N(CI.₅ alkyl)(Ci.₅ alkyl), -NH-OH, -N(CI.₅ alkyl)-OH, -NH-O(CI.₅ alkyl), -N(CI-5 alkyl)-O(Ci-5 alkyl), halogen, C1-5 haloalkyl, -O-(Ci-5 haloalkyl), -ON, -NO2, -CHO, -CO-(Ci-5 alkyl), -COOH, -CO-O-(Ci.₅ alkyl), -O-CO-(Ci.₅ alkyl), -CO-NH₂, -CO-NH(CI.₅ alkyl), -CO-N(CI.₅ alkyl)(Ci_₅ alkyl), -NH-CO-(CI-₅ alkyl), -N(CI.₅ alkyl)-CO-(Ci.₅ alkyl), -NH-CO-O-(CI.₅ alkyl), -N(CI.₅ alkyl)-CO-O-(Ci.₅ alkyl), -O-CO-NH-(CI-₅ alkyl), -O-CO-N(CI.₅ alkyl)-(Ci_₅ alkyl), -SO2-NH2, -SO₂-NH(CI.₅ alkyl), -SO₂-N(CI.₅ alkyl)(Ci_₅ alkyl), -NH-SO₂-(CI.5 alkyl), -N(CI.₅ alkyl)-SO₂-(Ci.₅ alkyl), -SO₂-(Ci.₅ alkyl), and -SO-(Ci.₅ alkyl).

Yet even more preferably, each R^s is independently selected from C1-5 alkyl, C2-5 alkenyl, C2-5 alkynyl, -OH, -SH, -NH₂, -NH-OH, halogen, C1.5 haloalkyl, -ON, -NO₂, -CHO, -CO-(Ci.₅ alkyl) (e.g, -CO- CH₃), -COOH, -CO-NH2, and -SO2-NH2.

Yet even more preferably, each R^s is independently selected from C1-5 alkyl, C2-5 alkenyl, C2-5 alkynyl, -OH, -SH, -NH₂, -NH-OH, halogen, C1.5 haloalkyl, -ON, -N0₂, -CHO, -COOH, -CO-NH₂, and -SO2-NH2.

Still more preferably, each R^s is independently selected from -OH, -SH, -NH2, -NH-OH, halogen, -ON, -N0₂, -CHO, -COOH, -CO-NH₂, and -SO2-NH2.

In formula (la) and in formula (lb), n is independently 0, 1, 2 or 3. Preferably, n is independently 0, 1, or 2. More preferably, n is independently 0 or 1. Even more preferably, n is 0.

It will be understood that the variable n indicates the number of substituents R^s which are attached to the respective phenyl moiety. If n is 0, there are no substituents R^s, so that the corresponding phenyl ring is unsubstituted (i.e., carries hydrogen in place of R^s). It will further be understood that the moiety of formula (la) or (lb) may be attached to (or immobilized in) the polymer via any ring carbon atom of the respective phenyl ring, which is reflected by a bond that extends into the phenyl ring, whereby the wavy line (at one end of this bond) indicates the point of attachment of the moiety of formula (la) or (lb).

More preferably, the boronic acid-based glucose-binding moiety comprises a moiety of formula (la-1) and/or a moiety of formula (lb-1):

In formula (la-1) and formula (lb-1), R^s and n are as defined herein above in connection with formula (la) and (lb), respectively.

The way in which the moiety of formula (la) (which is preferably a moiety of formula (la-1)) or the moiety of formula (lb) (which is preferably a moiety of formula (lb-1) is attached to the remainder of the polymer is not particularly limited, and any chemically feasible attachment is encompassed by the present invention. For example, any of these moieties may be attached via an amide linkage or an inversed amide linkage, e.g., via a group -NH-CO- or a group -CO-NH-. A particularly preferred attachment is illustrated in formulae (la-2) and (lb-2) below, or in formula (la-1) and (lb-1) above; further examples of preferred attachments are apparent from the disclosure of the methods for preparing the polymers and the monomers used, including any of those described in the example section.

Accordingly, even more preferably, the boronic acid-based glucose-binding moiety comprises a moiety of formula (la-2) and/or a moiety of formula (lb-2):

It is particularly preferred that the monomers comprising the moieties of formula (la-2) and of formula (lb-2) are N- substituted acrylamide monomers, as defined herein above.

In formula (la-2) and formula (lb-2), R^s and n are as defined herein above in connection with formula (la) and (lb), respectively. These groups/variables thus have the same meanings, including the same general and preferred meanings, as described herein above.

As explained above, n is most preferably 0. Accordingly, it is particularly preferred that the boronic acid-based glucose-binding moiety comprises a moiety of formula (la-3) and/or a moiety of formula (lb-3):

Preferably, the inhibitor moiety is an organic moiety comprising at least two hydroxyl groups attached to aliphatic carbon atoms. In other words, preferably the inhibitor moiety comprises an aliphatic diol moiety. It is preferred that between the oxygen atoms in said aliphatic group there is 3 or 4 bonds. It is noted that this definition is not meant to exclude the presence of additional hydroxyl groups in the moiety. It is further noted that the inhibitor moiety is to be selected so that the affinity requirements between the inhibitor moiety and the glucose-binding moiety as described herein above are preferably fulfilled.

However, the inhibitor may also include at least two hydroxyl groups attached to an aromatic group, such as an aryl group. For example, such inhibitors may include a 1 ,2-diyhdroxyphenyl moiety.

Preferably, the inhibitor moiety comprises a moiety of formula (Ila), a moiety of formula (lib) and/or a moiety of formula (lie):

While the inhibitor moiety may also comprise a moiety of formula (Ila) and/or a moiety of formula (lie) wherein each of the chiral centers in formula (Ila) and formula (lie) may have any configuration, it is preferred that these chiral centers all have the specific configuration depicted in formula (Ila) and formula (lie), respectively.

The moiety of formula (Ila) is preferably a moiety of formula (lla-1):

(lla-1) wherein q is an integer from 0 to 10, preferably wherein q is an integer from 0 to 5, more preferably wherein q is an integer from 0 to 2, more preferably wherein q is 0.

Preferably, the moiety of formula (lib) is a moiety of formula (llb-1):

Preferably, the moiety of formula (lie) is a moiety of formula (llc-1):

(Hc-1) wherein q is an integer from 1 to 10, preferably wherein q is an integer from 2 to 5, more preferably wherein q is 2 or 5.

More preferably, the inhibitor moiety comprises a moiety of formula (Ila), preferably a moiety of formula (lla-1), and/or a moiety of formula (lib), preferably a moiety of formula (llb-1), as described herein above.

The polymers of the present invention, in particular the polymeric hydrogels of the present invention, exhibit advantageous properties, as discussed above and as also demonstrated in the examples, and are therefore particularly suitable for use in the biosensors of the present invention for measuring (or sensing) the concentration of glucose.

The polymer comprised in the biosensor of the present invention behaves preferably as follows: In the absence of glucose, a boronic acid-based glucose-binding moiety binds to an inhibitor moiety, whereby the polymer (or polymeric hydrogel) is reversibly crosslinked. In the presence of glucose, the boronic acid-based glucose-binding moiety binds to glucose, whereby the bond between the boronic acid-based glucose-binding moiety and the inhibitor moiety is broken (i.e., glucose binds to the boronic acid-based glucose-binding moiety and thereby displaces any previously bound inhibitor moiety), which results in a swelling of the polymer (or the polymeric hydrogel). It is preferred that the extent of swelling is substantially linearly proportional to the concentration of glucose. Herein, the extent of swelling is preferably understood as AL/L, wherein AL is the change in linear dimensions of the polymer (or the polymeric hydrogel), and L is total linear dimension of said polymer (or said polymeric hydrogel). Accordingly, the biosensors comprising polymers as described herein preferably exhibit a substantially linear relationship, more preferably a linear relationship between the concentration of glucose and AL/L. As used herein, the term "substantially linear” preferably means within the value expected for a linear relationship, particularly with 10% tolerance (i.e., within ±10% of a linear relationship), more preferably with 5% tolerance, even more preferably with 2% tolerance.

As it is apparent to the skilled person, the dependence of the extent of swelling on the concentration of glucose allows detection of changes in glucose concentration. For example, a reference curve of the measured extent of swel ling/shri nking (AL/L) at multiple known concentrations of glucose can be prepared; by comparing a measured value of the extent of swelling/shrinking with the reference curve, the concentration of glucose can be determined.

Preferably, in the polymers comprised in the biosensor of the present invention, the boronic acid-based glucose- binding moiety and the inhibitor moiety are present in a molar ratio of from about 1 :0.5 to about 1 :4, preferably in a molar ratio of from about 1 :1 to about 1 :3, preferably in a molar ratio of from about 1 :1 to about 1 :2. This applies preferably to a biosensor comprising a polymer wherein the boronic acid-based glucose-binding moiety is a moiety of formula (la) and/or (lb) (which, as explained above, are interconvertible moieties) and wherein the inhibitor moiety is a moiety of formula (Ila), (lib) or (lie).

As used herein, whenever the term "about” is employed in connection with a numerical value, it preferably refers to ± 10% of the indicated numerical value, more preferably to ± 5%, even more preferably to ± 2%, even more preferably to ± 1 % of the indicated numerical value, and most preferably to the exact numerical value indicated. If the term "about” is used in connection with the endpoints of a range, it preferably refers to the range from the lower endpoint -10% of its indicated numerical value to the upper endpoint +10% of its indicated numerical value, more preferably to the range from of the lower endpoint -5% to the upper endpoint +5%, even more preferably to the range from of the lower endpoint -2% to the upper endpoint +2%, yet even more preferably to the range from the lower endpoint -1 % to the upper endpoint +1 %, and most preferably to the range defined by the exact numerical values of the lower endpoint and the upper endpoint. It is noted that the numerical value may also be a ratio, for example, a ratio used to express the composition of the polymer of the invention, as described herein above. While a ratio may be described as a division operation on two numbers, it can also be expressed as a single number resulting from said division. For example, the ratio of 1 :2 can be otherwise expressed as a ratio of 0.5. The aforementioned deviations of ± x% can be applied to a corresponding single number (resulting from said division operation), and the endpoints of the resulting range can each be converted back into a corresponding ratio. For example, a ratio of 1 :2 ± 10% can also be expressed as a ratio of 0.5 ± 10% or as a ratio of from 0.45 to 0.55, which corresponds to a ratio of from 1 : 1.82 to 1 : 2.22.

A further advantage of the polymer comprised in the biosensor of the present invention is the possibility of being used in different pH conditions. Accordingly, in the biosensors of the present invention the extent of swelling of the polymer (or the polymeric hydrogel) in the presence of glucose is substantially independent of the pH value in the range from about pH 7.4 to about pH 7.6. It is particularly preferred that the extent of swelling remains independent of the pH in a narrow range typical to that observed in human blood.

It is particularly preferred that the extent of swelling of the polymer (or the polymeric hydrogel) in the presence of glucose is substantially independent of the pH value in the range from about pH 6.9 to about pH 7.6. This pH range is particularly relevant in the case of application in the intensive care unit (ICU), wherein not only normal pH range of blood may be seen in treated patient, i.e., the range from about 7. 35 to about 7.45, but treated patients show a broader range of blood pH, including pathological pH values.

As used herein, the expression "substantially independent of the pH value” in a particular pH range preferably means that a maximum change/variation of the extent of swelling of 15%, understood as AL/L of 15% (corresponding to the sensitivity (0-20 mM glucose)), is observed within said pH range, more preferably a maximum change/variation of 10%, even more preferably a maximum change/variation of 5%. The term "substantially independent of” also includes a specific reference to the narrower meaning of "independent of”.

In an alternative embodiment of the present invention, the boronic acid-based glucose-binding moiety comprises a moiety of formula (Ic):

In formula (Ic), R^L is selected from C4-8 alkylene, C4-8 alkenylene, C4-8 alkynylene, -(C0-2 alkylene)-arylene-(Co-2 alkylene)- and -(C0-2 alkylene)-heteroarylene-(Co-2 alkylene)-, wherein the arylene moiety in said -(C0-2 alkylene)- arylene-(Co-2 alkylene)- and the heteroarylene moiety in said -(C0-2 alkylene)-heteroarylene-(Co-2 alkylene)- are each optionally substituted with one or more R^s, and wherein one or more -CH2- units in said C4-8 alkylene, said C4-8 alkenylene or said C4-8 alkynylene are each optionally replaced by a group independently selected from -O-, -S-, -NH- and -N(Ci_₅ alkyl)-.

Preferably, R^L is selected from C4-8 alkylene, C4-8 alkenylene, C4-8 alkynylene, -(C0-2 alkylene)-arylene-(Co-2 alkylene)- and -(C0-2 alkylene)-heteroarylene-(Co-2 alkylene)-, wherein one or more (e.g., one, two or three; particularly one) -CH2- units in said C4-8 alkylene, said C4-8 alkenylene or said C4-8 alkynylene are each optionally replaced by a group independently selected from -O-, -S-, -NH- and -N(CI-5 alkyl)-.

More preferably, R^L is selected from C4-8 alkylene, C4-8 alkenylene, C4-8 alkynylene, -(C1-2 alkylene)-arylene-(Ci-2 alkylene)- and -(C1-2 alkylene)-heteroarylene-(Ci-2 alkylene)-, wherein one or two (particularly one) -CH2- units in said C4-8 alkylene, said C4-8 alkenylene or said C4-8 alkynylene are each optionally replaced by a group independently selected from -O-, -S-, -NH- and -N(CI-5 alkyl)-. Corresponding examples include, inter alia, -(C1-3 alkylene)-O-(Ci-3 alkylene)-, -(C1-3 alkylene)-S-(Ci-3 alkylene)-, or -(C1-3 alkylene)-NH-(Ci-3 alkylene)-, particularly -(CH₂)I-3-O-(CH₂)I-3-, -(CH₂)I-3-S-(CH₂)I-3-, or -(CH₂)I-3-NH-(CH₂)I-3-.

Even more preferably, R^L is selected from C4-8 alkylene, C4-8 alkenylene, C4-8 alkynylene, -(C1-2 alkylene)-arylene- (C1-2 alkylene)- and -(C1-2 alkylene)-heteroarylene-(Ci-2 alkylene)-. Corresponding examples include, inter alia, -CH2-(phen-1 ,4-diyl)-CH2- or -CH2-anthracen-9,10-diyl-CH2-.

Yet even more preferably, R^L is selected from C4-8 alkylene, C4-8 alkenylene and C4-8 alkynylene. It is furthermore preferred that said alkylene, said alkenylene and said alkynylene are each linear.

Still more preferably, R^L is C4-8 alkylene, particularly a linear C4-8 alkylene. Corresponding preferred examples of R^L include 1,4-n-butylene (i.e., -(CH2)4-), 1 ,5-n-pentylene (i.e., -(CH2)5-) and 1,6-n-hexylene (i.e., -(CH2)e-). A particularly preferred group R^L is 1,6-n-hexylene, i.e. -(CH2)e-.

In formula (Ic), each R^s is independently selected from C1-5 alkyl, C2-5 alkenyl, C2-5 alkynyl, -(C0-3 alkylene)-OH, -(C0-3 alkylene)-O(Ci-5 alkyl), -(C0-3 alkylene)-O(Ci-5 alkylene)-OH, -(C0-3 alkylene)-O(Ci-5 alkylene)-O(Ci-5 alkyl), -(C0-3 alkylene)-SH, -(C0-3 alkylene)-S(Ci-5 alkyl), -(C0-3 alkylene)-S(Ci-5 alkylene)-SH, -(C0-3 alkylene)-S(Ci-5 alkylene)-S(Ci-5 alkyl), -(C0-3 alkylene)-NH2, -(C0-3 alkylene)-NH(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)(Ci.5 alkyl), -(C0-3 alkylene)-NH-OH, -(C0-3 alkylene)-N(Ci.₅ alkyl)-OH, -(C0-3 alkylene)-NH-O(Ci.₅ alkyl), -(C0-3 alky lene)-N (C1-5 alkyl)-O(Ci-5 alkyl), -(C0-3 alky lene)-halogen, -(C0-3 alkylene)-(Ci-5 haloalkyl), -(C0-3 alkylene)-O-(Ci-5 haloalkyl), -(C0-3 alkylene)-CN, -(C0-3 alkylene)-NO2, -(C0-3 alkylene)-CHO, -(C0-3 alkylene)-CO-(Ci-5 alkyl), -(C0-3 alkylene)-COOH, -(C0-3 alkylene)-C0-0-(Ci-5 alkyl), -(C0-3 alkylene)-0-C0-(Ci-5 alkyl), -(C0-3 alkylene)-C0-NH2, -(C0-3 alkylene)-C0-NH(Ci-5 alkyl), -(C0-3 alkylene)-C0-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-C0-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-C0-(Ci-5 alkyl), -(C0-3 alkylene)-NH-C0-0-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-C0-0-(Ci-5 alkyl), -(C0-3 alkylene)-0-C0-NH-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO- N(CI-5 alkyl)-(Ci-5 alkyl), -(C0-3 alkylene)-SO2-NH2, -(C0-3 alkylene)-SO2-NH(Ci-5 alkyl), -(C0-3 alkylene)-SO2-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-SO2-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-SO2-(Ci-5 alkyl), -(C0-3 alkylene)-SO2-(Ci-5 alkyl), -(C0-3 alkylene)-S0-(Ci-5 alkyl), -(C0-5 alkylene)-carbocyclyl, and -(C0-5 alkylene)-heterocyclyl, wherein one or more -CH2- units in the alkylene moiety in said -(C0-5 alkylene)-carbocyclyl and/or in the alkylene moiety in said -(C0-5 alkylene)-heterocyclyl are each optionally replaced by a group independently selected from -O-, -CO-, -CO-O-, -O-CO-, -NH-, -N(CI-5 alkyl)-, -NH-CO-, -N(CI-5 alkyl)-CO-, -CO-NH-, -CO-N(CI.₅ alkyl)-, -S-, -SO-, -SO₂-, -SO2-NH-, -SO₂-N(CI.₅ alkyl)-, -NH-SO2-, and -N(CI.₅ alkyl)-SO2-, and further wherein the carbocyclyl moiety in said -(C0-5 alkylene)-carbocyclyl and the heterocyclyl moiety in said -(C0-5 alkylene)-heterocyclyl are each optionally substituted with one or more groups independently selected from C1-5 alkyl, C2-5 alkenyl, C2-5 alkynyl, -OH, -O(Ci-5 alkyl), -O(Ci-5 alkylene)-OH, -O(Ci-5 alkylene)-O(Ci-5 alkyl), -SH, -S(Ci_₅ alkyl), -S(Ci_₅ alkylene)-SH, -S(Ci.₅ alkylene)-S(Ci.₅ alkyl), -NH₂, -NH(CI.₅ alkyl), -N(CI.₅ alkyl)(Ci.5 alkyl), -NH-OH, -N(Ci_₅ alkyl)-OH, -NH-O(CI.₅ alkyl), -N(CI.₅ alkyl)-O(Ci.₅ alkyl), halogen, C1.5 haloalkyl, -O-(Ci.₅ haloalkyl), -CF₃, -ON, -NO₂, -OHO, -CO-(Ci.₅ alkyl), -COOH, -CO-O-(Ci.₅ alkyl), -O-CO-(Ci.₅ alkyl), -CO-NH2, -CO-NH(CI-5 alkyl), -CO-N(CI.₅ alkyl)(Ci_₅ alkyl), -NH-CO-(CI.₅ alkyl), -N(CI.₅ alkyl)-CO-(Ci.₅ alkyl), -NH-CO-O-(CI-5 alkyl), -N(CI.₅ alkyl)-CO-O-(Ci.₅ alkyl), -O-CO-NH-(CI.₅ alkyl), -O-CO-N(CI.₅ alkyl)-(Ci.₅ alkyl), -SO2-NH2, -SO₂-NH(CI.5 alkyl), -SO₂-N(CI.₅ alkyl)(Ci_₅ alkyl), -NH-SO₂-(CI.₅ alkyl), -N(Ci_₅ alkyl)-SO₂-(Ci.₅ alkyl), -SO2-(Ci-5 alkyl), -SO-(Ci-5 alkyl), cycloalkyl, and heterocycloalkyl.

Preferably, each R^s is independently selected from C1-5 alkyl, C2-5 alkenyl, C2-5 alkynyl, -(C0-3 alkylene)-OH, -(C0-3 alkylene)-O(Ci-5 alkyl), -(C0-3 alkylene)-O(Ci-5 alkylene)-OH, -(C0-3 alkylene)-O(Ci-5 alkylene)-O(Ci-5 alkyl), -(C0-3 alkylene)-SH, -(C0-3 alkylene)-S(Ci-5 alkyl), -(C0-3 alkylene)-S(Ci-5 alkylene)-SH, -(C0-3 alkylene)-S(Ci-5 alkylene)-S(Ci-5 alkyl), -(C0-3 alkylene)-NH2, -(C0-3 alkylene)-NH(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)(Ci-5 alkyl), -(Co-3 alkylene)-NH-OH, -(C0-3 alkylene)-N(Ci.₅ alkyl)-OH, -(C0-3 alkylene)-NH-O(Ci.₅ alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-O(Ci-5 alkyl), -(C0-3 alky lene)-halogen, -(C0-3 alkylene)-(Ci-5 haloalkyl), -(C0-3 alkylene)-O-(Ci-5 haloalkyl), -(C0-3 alkylene)-CN, -(C0-3 alkylene)-NO2, -(C0-3 alkylene)-CHO, -(C0-3 alkylene)-CO-(Ci-5 alkyl), -(C0-3 alkylene)-COOH, -(C0-3 alkylene)-CO-O-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO-(Ci-5 alkyl), -(C0-3 alkylene)-CO-NH2, -(C0-3 alkylene)-CO-NH(Ci-5 alkyl), -(C0-3 alkylene)-CO-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-CO-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-CO-(Ci-5 alkyl), -(C0-3 alkylene)-NH-CO-O-(Ci-5 alkyl), -(Co-3 alkylene)-N(Ci-5 alkyl)-CO-O-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO-NH-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO- N(CI-5 alkyl)-(Ci-5 alkyl), -(C0-3 alkylene)-SO2-NH2, -(C0-3 alkylene)-SO2-NH(Ci-5 alkyl), -(C0-3 alkylene)-SO2-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-SO2-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-SO2-(Ci-5 alkyl), -(C0-3 alkylene)-SO2-(Ci-5 alkyl), -(C0-3 alkylene)-SO-(Ci-5 alkyl), -(C0-5 alkylene)-carbocyclyl, and -(C0-5 alkylene)-heterocyclyl. More preferably, each R^s is independently selected from C1-5 alkyl, C2-5 alkenyl, C2-5 alkynyl, -(C0-3 alkylene)-OH, -(C0-3 alkylene)-O(Ci-5 alkyl), -(C0-3 alkylene)-O(Ci-5 alkylene)-OH, -(C0-3 alkylene)-O(Ci-5 alkylene)-O(Ci-5 alkyl), -(C0-3 alkylene)-SH, -(C0-3 alkylene)-S(Ci-5 alkyl), -(C0-3 alkylene)-S(Ci-5 alkylene)-SH, -(C0-3 alkylene)-S(Ci-5 alkylene)-S(Ci-5 alkyl), -(C0-3 alkylene)-NH2, -(C0-3 alkylene)-NH(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)(Ci-₅ alkyl), -(C0-3 alkylene)-NH-OH, -(C0.3 alkylene)-N(Ci.₅ alkyl)-OH, -(C0.3 alkylene)-NH-O(Ci.₅ alkyl), -(C0-3 alky lene)-N (C1-5 alkyl)-O(Ci-5 alkyl), -(C0-3 alky lene)-halogen, -(C0-3 alkylene)-(Ci-5 haloalkyl), -(C0-3 alkylene)-O-(Ci-5 haloalkyl), -(C0-3 alkylene)-CN, -(C0-3 alkylene)-NO2, -(C0-3 alkylene)-CHO, -(C0-3 alkylene)-CO-(Ci-5 alkyl), -(C0-3 alkylene)-COOH, -(C0-3 alkylene)-CO-O-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO-(Ci-5 alkyl), -(C0-3 alkylene)-CO-NH2, -(C0-3 alkylene)-CO-NH(Ci-5 alkyl), -(C0-3 alkylene)-CO-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-CO-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-CO-(Ci-5 alkyl), -(C0-3 alkylene)-NH-CO-O-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-CO-O-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO-NH-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO- N(CI-5 alkyl)-(Ci-5 alkyl), -(C0-3 alkylene)-SO2-NH2, -(C0-3 alkylene)-SO2-NH(Ci-5 alkyl), -(C0-3 alkylene)-SO2-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-SO2-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-SO2-(Ci-5 alkyl), -(C0-3 alkylene)-SO2-(Ci-5 alkyl), and -(C0-3 alkylene)-SO-(Ci-5 alkyl).

In formula (Ic), n' and n” are each independently selected from 0, 1, 2, 3, and 4. Preferably, n' and n” are each independently selected from 0, 1 and 2. More preferably, n' and n” are each independently selected from 0 and 1. Even more preferably, n' and n” are each 0.

The boronic acid-based glucose-binding moiety comprising a moiety of formula (Ic) may comprise a moiety of formula (Ic'):

Accordingly, the moiety of formula (Ic) may be a moiety of formula (lc').

In formula (Ic'), R^L, R^s, n' and n” are as defined in formula (Ic). Thus, the general and preferred meanings of these groups/variables as described herein above in the context of formula (Ic) likewise apply to formula (Ic').

In formula (Ic'), R² is a group selected from -CH2-CONH-(CH2CH2O)_P-(CI-5 alkyl), C1-5 alkyl, -(C0-3 alkylene)-aryl, and -(C0-3 alkylene)-heteroaryl, wherein p is an integer in the range from 1 to 10, wherein the aryl in said -(C0-3 alky lene)-ary I and the heteroaryl in said -(C0-3 alky lene)-heteroary I are each optionally substituted with one or more (e.g., one, two or three) R^s.

Preferably, R² is a group selected from -CH2-CONH-(CH2CH2O)_P-(CI-5 alkyl) (e.g., -CH2-CONH-(CH2CH2O)_P-CH3 or -CH2-CONH-(CH2CH2O)_P-CH2CH3), C1-5 alkyl (e.g., methyl or ethyl), -(C1-3 alkylene)-aryl (e.g., -Chfe-aryl), and -(C1-3 alkylene)-heteroaryl (e.g., -CH2-heteroaryl), wherein the aryl in said -(C1-3 alkylene)-aryl and the heteroaryl in said -(C1-3 alkylene)-heteroaryl are each optionally substituted with one or more R^s. The aryl in said -(C1-3 alkylene)-aryl may be, e.g., phenyl or a fused polycyclic aryl, such as, e.g., naphthyl, fluorenyl, anthracenyl, phenanthrenyl, phenalenyl, tetracenyl, chrysenyl, triphenylenyl, pyrenyl, pentacenyl, perylenyl, or benzo[a]pyrenyl; a corresponding example of R² is -CH2-(pyren-1-yl).

More preferably, R² is -CH2-CONH-(CH2CH2O)_p-(Ci-5 alkyl), C1-5 alkyl, or -Chfe-aryl, wherein p is an integer in the range from 1 to 10, wherein the aryl in said -CFh-aryl is optionally substituted with one or more R^s.

Even more preferably, R² is a group -CH2-CONH-(CH2CH2O)_p-(Ci-5 alkyl), wherein p is an integer in the range from 1 to 10. The C1-5 alkyl in said -CH2-CONH-(CH2CH2O)_p-(Ci-5 alkyl) is preferably methyl or ethyl, more preferably methyl. The boronic acid-based glucose-binding moiety comprising a moiety of formula (Ic) may comprise a moiety of formula (Ic”):

Accordingly, the moiety of formula (Ic) may be a moiety of formula (Ic”).

In formula (Ic”), R^L, R^s, n' and n” are as defined in formula (Ic). Thus, the general and preferred meanings of these groups/variables as described herein above in the context of formula (Ic) likewise apply to formula (Ic").

In formula (Ic”), R¹ is a group -CONH-CH2CH2-(O-CH2CH2)_m-, wherein m is an integer in the range from 1 to 10, or a group -CH2-arylene. Preferably, R¹ is a group -CONH-CH2CH2-(O-CH2CH2)_m-, wherein m is an integer in the range from 1 to 10, or a group -CH2-phenylene (e.g., -CH2-(phen-1 ,4-diyl)). More preferably, R¹ is a group -CONH- CH₂CH2-(O-CH₂CH2)m-, wherein m is an integer in the range from 1 to 10. It is further preferred that R¹ is attached via its terminal -CH2- group to the nitrogen atom in formula (Ic”).

Preferably, m is selected from 2, 3, 4, 5, and 6. A particularly preferred value of m is 4.

Preferably, the boronic acid-based glucose-binding moiety comprising a moiety of formula (Ic) comprises a moiety of formula (lc-1):

In formula (lc-1), R^L, R^s, n' and n” are as defined in formula (Ic).

In formula (lc-1), R¹ is a group -CONH-CH2CH2-(O-CH2CH2)_m-, wherein m is an integer in the range from 1 to 10, or a group -CH2-arylene. Preferably, R¹ is a group -CONH-CH2CH2-(O-CH2CH2)_m-, wherein m is an integer in the range from 1 to 10, or a group -CH2-phenylene (e.g., -CH2-(phen-1 ,4-diyl)). More preferably, R¹ is a group -CONH- CH₂CH2-(O-CH₂CH2)m-, wherein m is an integer in the range from 1 to 10. It is further preferred that R¹ is attached via its terminal -CH2- group to the nitrogen atom in formula (lc-1 ).

In formula (lc-1), R² is a group selected from -CH2-CONH-(CH2CH2O)_P-(CI-5 alkyl), C1-5 alkyl, -(C0-3 alkylene)-aryl, and -(C0-3 alkylene)-heteroaryl, wherein p is an integer in the range from 1 to 10, wherein the aryl in said -(C0-3 alky lene)-ary I and the heteroaryl in said -(C0-3 alky lene)-heteroary I are each optionally substituted with one or more R^s.

Preferably, R² is a group selected from -CH2-CONH-(CH2CH2O)_P-(CI-5 alkyl) (e.g., -CH2-CONH-(CH2CH2O)_P-CH3 or -CH2-CONH-(CH2CH2O)_P-CH2CH3), C1-5 alkyl (e.g., methyl or ethyl), -(C1-3 alkylene)-aryl, and -(C1-3 alkylene)- heteroaryl, wherein the aryl in said -(C1-3 alkylene)-aryl and the heteroaryl in said -(C1-3 alkylene)-heteroaryl are each optionally substituted with one or more R^s. The aryl in said -(C1-3 alky lene)-aryl may be, e.g., phenyl or a fused polycyclic aryl, such as, e.g., naphthyl, fluorenyl, anthracenyl, phenanthrenyl, phenalenyl, tetracenyl, chrysenyl, triphenylenyl, pyrenyl, pentacenyl, perylenyl, or benzo[a]pyrenyl; a corresponding example of R² is -CH2-(pyren-1- yi).

More preferably, R² is a group -CH2-CONH-(CH2CH2O)_P-(CI-5 alkyl) or a group -(C1-5 alkyl), wherein p is an integer in the range from 1 to 10.

Even more preferably, R² is a group -CH2-CONH-(CH2CH2O)_P-(CI-5 alkyl), wherein p is an integer in the range from 1 to 10. The C1-5 alkyl in said -CH2-CONH-(CH2CH2O)_P-(CI-5 alkyl) is preferably methyl or ethyl, more preferably methyl.

As explained above, p is an integer in the range from 1 to 10. Preferably, p is an integer in the range from 2 to 8. More preferably, p is 3, 4, 5, 6 or 7. A particularly preferred example of p is 5.

In accordance with the above, it is particularly preferred that in formula (lc-1), n' and n” are each 0, R^L is -(CH2)e-, and R² is a group -CH2-CONH-(CH2CH2O)_P-(CI-5 alkyl), wherein p is an integer in the range from 1 to 10 (e.g., 3, 4, 5, 6 or 7).

Preferred examples of moieties of formula (Ic) or of formula (lc-1) are selected from the following moieties of formulae (lc-1 a), (lc-1 b), (lc-1c) and (lc-1d):

(lc-1c)

(lc-1d)

The inhibitor moiety in the embodiment of the invention wherein the boronic acid-based glucose-binding moiety comprises a moiety of formula (Ic) is as described herein. Preferably, in the embodiment of the invention wherein the boronic acid-based glucose-binding moiety comprises a moiety of formula (Ic), the inhibitor moiety comprises a moiety of the following formula (lie):

In this embodiment, i.e., if the boronic acid-based glucose-binding moiety comprises a moiety of formula (Ic), the inhibitor moiety more preferably comprises a moiety of formula (llc-1):

wherein q is an integer from 1 to 10, preferably wherein q is an integer from 2 to 5, more preferably wherein q is 2 or 5.

Preferably, in this embodiment, the boronic acid-based glucose-binding moiety and the inhibitor moiety are present in a molar ratio of from about 1 :0.5 to about 1:2, more preferably are present in a molar ratio of from about 0.8:1 to about 1 .2, even more preferably are present in a molar ratio of about 1 : 1.

In a further embodiment of the present invention wherein the boronic acid-based glucose-binding moiety comprises a moiety of formula (Ic), the inhibitor moiety comprises a moiety of the following formula (lib):

In the above embodiment, the inhibitor moiety preferably comprises a moiety of formula (llb-1):

(llb-1)

In this particular embodiment, preferably the boronic acid-based glucose-binding moiety and the inhibitor moiety are present in a molar ratio of from about 3: 1 to about 1 :3, more preferably in a molar ration of from about 2: 1 to about 1 :3, even more preferably the boronic acid-based glucose-binding moiety and the inhibitor moiety are present in a molar ratio of from about 1 :1 to about 1 :3, yet even more preferably the boronic acid-based glucose-binding moiety and the inhibitor moiety are present in a molar ratio of from about 1 : 1 to about 1 :2, still more preferably the boronic acid-based glucose-binding moiety and the inhibitor moiety are present in a molar ratio of about 1 :2.

The polymer, which is preferably a polymeric hydrogel, has been described herein above. In accordance with established practice in the art, the polymer can be defined according to the process of its preparation, in particular in terms of the monomers that are being polymerized. Accordingly, it is preferred that the polymer (or the polymeric hydrogel) is obtainable in a polymerization reaction of a composition comprising:

(i) an acrylamide monomer comprising the boronic acid-based glucose binding moiety, and

(ii) an acrylamide monomer comprising the inhibitor moiety.

It will be understood that the boronic acid-based glucose binding moiety in the acrylamide monomer (i) and the inhibitor moiety in the acrylamide monomer (ii) are each attached to the remainder of the respective monomer through an attachment point, as shown herein above. It is to be noted that some formulae showing preferred embodiments of the boronic acid-based glucose binding moiety or the inhibitor moiety include an -NH-CO- moiety; in the corresponding acrylamide monomers (i) or (ii), this -NH-CO- moiety preferably forms part of the acrylamide moiety, i.e., the -CO- in said -NH-CO- moiety is preferably attached to an ethylene group (-CHOH2), thereby forming the acrylamide moiety -NH-CO-CH=CH2.

Accordingly, preferred examples of the acrylamide monomer (i), particularly in the case that a boronic acid-based glucose-binding moiety comprising a moiety of formula (la) or (lb) is used, include the following monomers:

In the case that the boronic acid-based glucose binding moiety comprises a moiety of formula (Ic), the corresponding monomer used for the polymerization reaction, i.e., the acrylamide monomer (i), is preferably selected from any of the following monomers:

more preferably from

5

Preferably, in the polymers of the present invention and biosensors comprising the polymers of the present invention, the acrylamide monomer comprising an inhibitor moiety (ii) is selected from

(wherein q is an integer from 0 to 10, preferably wherein q is an integer from 0 to 5, more preferably wherein q is an integer from 0 to 2, even more preferably wherein q is 0), and

(wherein q is an integer from 0 to 10, preferably wherein q is an integer from 0 to 5, more preferably wherein q is an integer from 0 to 2, even more preferably wherein q is 0).

Preferably, the composition used in the polymerization reaction further comprises:

(ill) an acrylamide monomer free of boronic-acid moiety and free of inhibitor moiety, and

(iv) a crosslinker acrylamide monomer.

The acrylamide monomer free of boronic-acid moiety and free of inhibitor moiety is a monomer comprising a moiety:

preferably comprising exactly one copy of such a moiety, but not comprising any boronic-acid moiety and not comprising any inhibitor moiety (e.g., not comprising any of the inhibitor moieties described herein, preferably not comprising more than one hydroxyl group). Such monomers are not particularly limited and preferably include an unsubstituted acrylamide monomer (wherein the above-depicted moiety is attached to a hydrogen) or substituted acrylamide monomers wherein the above-depicted moiety is, e.g., attached to a hydroxylalkyl group or an ethylene glycol oligomer. Exemplary preferred monomers (ill) are selected from the following monomers:

, wherein q is an integer from 0 to 10; preferably wherein q is an integer from 2 to 5, more preferably wherein q is 2 or 5. One single type of monomer (ill) or more than one type (e.g., two or three types) of the monomers (ill) may be present in the composition whose polymerization affords the polymer of the present invention.

The crosslinker acrylamide monomer (iv) preferably comprises at least two copies of the following moiety:

preferably it comprises exactly two copies of the above-depicted moiety. Moreover, it is preferably free of boronic- acid moiety and free of inhibitor moiety.

Preferably, the crosslinker acrylamide monomer (iv) comprises (or is) a monomer selected from:

wherein q is an integer from 0 to 10, preferably wherein q is an integer from 2 to 5, more preferably wherein q is 2 or 5.

Preferably, for the polymer (more preferably, the polymeric hydrogel) of the present invention, the acrylamide monomer (I) constitutes between 6 and 10 mol% of the acrylamide-based components in said composition used for the polymerization reaction. It is further preferred that the monomers (I) and (II) are present in a molar ratio of about 1 : 1. However, the invention also relates to the use of other ratios of the monomers (I) and (II), specifically to the molar ratios defined herein above in connection with the boronic acid-based glucose binding moiety and the inhibitor moiety. It is to be understood that these specific molar ratios can likewise be used for the acrylamide monomers (I) and (ii).

Preferably, in the polymer of the present invention, the monomer (ill) constitutes between 60 and 84 mol% of acrylamide-based components in said composition used for the polymerization reaction.

Preferably, in the polymer of the present invention, the crosslinker acrylamide monomer (iv) constitutes between 0.1 and 4 mol% of the acrylamide-based components in said composition used for the polymerization reaction. More preferably, in the polymer of the present invention, the crosslinker acrylamide monomer (iv) constitutes between 1 and 4 mol% of the acrylamide-based components in said composition used for the polymerization reaction.

The polymers and, as applicable, the polymeric hydrogels of the present invention can be prepared according to the methods described herein above and as illustrated in the examples section. The monomers required for the synthesis of the polymers of the present invention, if not available commercially, can be obtained according to the methods as illustrated in the examples section. The present invention accordingly further relates to each of the monomers and each of the intermediates used in the synthesis of such monomer as described herein, including in particular each of the monomers and each of the intermediates described in the examples section. Accordingly, it is preferred that the glucose-binding moieties as well as the inhibitor moieties are incorporated into the monomers and then copolymerized into the polymer of the invention (preferably a polymeric hydrogel) comprising said glucose-binding moieties and said inhibitor moieties. However, the present invention also encompasses embodiments wherein the glucose-binding moiety and/or the inhibitor moiety is incorporated into a previously prepared polymer through a modification of said polymer. One exemplary way of such modification is a Michael-like addition reaction of -SH group, present in a preformed polymer as thiolactone to acrylamide moiety.

The present invention further provides a biosensor for measuring the concentration of glucose, the biosensor comprising a polymer comprising a boronic acid-based glucose-binding moiety, wherein said boronic acid-based glucose-binding moiety is immobilized in said polymer, wherein in the presence of glucose, the boronic acid-based glucose-binding moiety binds to glucose, which results in a change of volume of the polymer. The boronic acidbased glucose-binding moiety is as described hereinabove.

In a first specific embodiment, the boronic acid-based glucose-binding moiety comprises a moiety of formula (la-2) and/or a moiety of formula (I b-2):

wherein n is 0; and wherein the inhibitor moiety comprises a moiety of formula (lib):

It is preferred that the monomers comprising the moiety of formula (la-2) and/or the moiety of formula (I b-2), as well as the moiety of formula (lib), are N-substituted acrylamide monomers, as defined herein above.

Thus, preferably, in this first specific embodiment, the polymer comprised in the biosensor of the present invention is obtainable in a polymerization reaction of a composition comprising:

(i) an acrylamide monomer comprising the boronic acid-based glucose binding moiety, according to the formula:

(ii) an acrylamide monomer comprising the inhibitor moiety, according to the formula:

Otherwise, the polymer is as described herein, in particular considering the monomer composition of the polymer of the invention.

In a second specific embodiment, the boronic acid-based glucose-binding moiety comprises a moiety of formula (la-2) and/or a moiety of formula (lb-2):

wherein n is 0; and wherein the inhibitor moiety comprises a moiety of formula (Ila):

Preferably, the boronic acid-based glucose-binding moiety and the inhibitor moiety are present in a molar ratio of from about 1 :1 .5 to about 1 :2.5, preferably about 1 :2.

It is preferred that the monomers comprising the moiety of formula (la-2) and/or the moiety of formula (lb-2), as well as the moiety of formula (Ila), are N-substituted acrylamide monomers, as defined herein above. Thus, preferably, in this second specific embodiment, the polymer comprised in the biosensor of the present invention is obtainable in a polymerization reaction of a composition comprising:

, wherein q is an integer from 0 to 10 (i.e., 0,

1 , 2, 3, 4, 5, 6, 7, 8, 9 or 10), preferably wherein q is an integer from 0 to 5, more preferably wherein q is an integer from 0 to 2, even more preferably wherein q is 0. Otherwise, the polymer is as described herein, in particular considering the monomer composition of the polymer of the invention.

In a third specific embodiment, the boronic acid-based glucose-binding moiety comprises a moiety of formula (lc-1):

(lc-1) wherein: n' and n” are each 0;

R¹ is a group -CONH-CH2CH2-(O-CH2CH2)_m- or a group -CH2-arylene (e.g., -CH2-phenylene, such as -CH2-(phen- 1 ,4-diyl)), wherein R¹ is attached via its terminal -CH2- group to the nitrogen atom in formula (lc-1); preferably, R¹ is a group -CONH-CH₂CH2-(O-CH₂CH2)m-; m is an integer in the range from 1 to 10, preferably m is selected from 2, 3, 4, 5, and 6, more preferably m is 4; R² is a group -CH2-CONH-(CH2CH2O)_P-(CI-5 alkyl), wherein p is an integer in the range from 1 to 10, preferably p is an integer in the range from 2 to 8, more preferably, p is 3, 4, 5, 6 or 7, even more preferably p is 5; and R^L is -(CH2)e-; and wherein the inhibitor moiety comprises a moiety of formula (lib):

It is preferred that the monomers comprising the moiety of formula (lc-1) as well as the moiety of formula (lib), are N-substituted acrylamide monomers, as defined herein above.

Thus, preferably, in this third specific embodiment, the polymer comprised in the biosensor of the present invention is obtainable in a polymerization reaction of a composition comprising:

and

In a fourth specific embodiment, the boronic acid-based glucose-binding moiety comprises a moiety of formula (lc-1):

wherein: n' and n” are each 0;

R¹ is a group -CONH-CH2CH2-(O-CH2CH2)_m- or a group -CH2-arylene (e.g., -CH2-phenylene, such as -CH2-(phen- 1 ,4-diyl)), wherein R¹ is attached via its terminal -CH2- group to the nitrogen atom in formula (lc-1); preferably, R¹ is a group -CONH-CH₂CH2-(O-CH₂CH2)m-; m is an integer in the range from 1 to 10, preferably m is selected from 2, 3, 4, 5, and 6, more preferably m is 4;

R² is a group -CH2-CONH-(CH2CH2O)_P-(CI-5 alkyl), wherein p is an integer in the range from 1 to 10, preferably p is an integer in the range from 2 to 8, more preferably, p is 3, 4, 5, 6 or 7, even more preferably p is 5; and

R^L is -(CH2)e-; and wherein the inhibitor moiety comprises a moiety of formula (lie):

Preferably, the boronic acid-based glucose-binding moiety and the inhibitor moiety are present in a molar ratio of from about 1 :0.5 to about 1 : 1.5, preferably about 1 : 1.0.

It is preferred that the monomers comprising the moiety of formula (lc-1) as well as the moiety of formula (lie), are N-substituted acrylamide monomers, as defined herein above.

Thus, preferably, in this fourth specific embodiment, the polymer comprised in the biosensor of the present invention is obtainable in a polymerization reaction of a composition comprising: (I) an acrylamide monomer comprising the boronic acid-based glucose binding moiety, according to the formula:

and (ii) an acrylamide monomer comprising the inhibitor moiety, according to the formula:

wherein q is an integer from 0 to 10, preferably wherein q is an integer from 0 to 5, more preferably wherein q is an integer from 0 to 2, even more preferably wherein q is 0. Otherwise, the polymer is as described herein, in particular considering the monomer composition of the polymer of the invention.

In an alternative embodiment of the present invention, the boronic acid-based glucose-binding moiety comprises a moiety of formula (Id):

In formula (Id), each R^s is independently selected from C1-5 alkyl, C2-5 alkenyl, C2-5 alkynyl, -(C0-3 alkylene)-OH, -(C0-3 alkylene)-O(Ci-5 alkyl), -(C0-3 alkylene)-O(Ci-5 alkylene)-OH, -(C0-3 alkylene)-O(Ci-5 alkylene)-O(Ci-5 alkyl), -(C0-3 alkylene)-SH, -(C0-3 alkylene)-S(Ci-5 alkyl), -(C0-3 alkylene)-S(Ci-5 alkylene)-SH, -(C0-3 alkylene)-S(Ci-5 alkylene)-S(Ci-5 alkyl), -(C0-3 alkylene)-NH2, -(C0-3 alkylene)-NH(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-OH, -(C0-3 alkylene)-N(Ci_₅ alkyl)-OH, -(C0-3 alkylene)-NH-O(Ci.₅ alkyl), -(C0-3 alky lene)-N (C1-5 alkyl)-0(Ci-5 alkyl), -(C0-3 alky lene)-halogen, -(C0-3 alkylene)-(Ci-5 haloalkyl), -(C0-3 alkylene)-O-(Ci-5 haloalkyl), -(C0-3 alkylene)-CN, -(C0-3 alkylene)-NO2, -(C0-3 alkylene)-CHO, -(C0-3 alkylene)-CO-(Ci-5 alkyl), -(C0-3 alkylene)-COOH, -(C0-3 alkylene)-CO-O-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO-(Ci-5 alkyl), -(C0-3 alkylene)-CO-NH2, -(C0-3 alkylene)-CO-NH(Ci-5 alkyl), -(C0-3 alkylene)-CO-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-CO-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-CO-(Ci-5 alkyl), -(C0-3 alkylene)-NH-CO-O-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-CO-O-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO-NH-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO- N(CI-5 alkyl)-(Ci-5 alkyl), -(C0-3 alkylene)-SO2-NH2, -(C0-3 alkylene)-SO2-NH(Ci-5 alkyl), -(C0-3 alkylene)-SO2-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-SO2-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-SO2-(Ci-5 alkyl), -(C0-3 alkylene)-SO2-(Ci-5 alkyl), -(C0-3 alkylene)-SO-(Ci-5 alkyl), -(C0-5 alkylene)-carbocyclyl, and -(C0-5 alkylene)-heterocyclyl, wherein one or more -CH2- units in the alkylene moiety in said -(C0-5 alkylene)-carbocyclyl and/or in the alkylene moiety in said -(C0-5 alkylene)-heterocyclyl are each optionally replaced by a group independently selected from -O-, -CO-, -CO-O-, -O-CO-, -NH-, -N(CI-5 alkyl)-, -NH-CO-, -N(CI-5 alkyl)-CO-, -CO-NH-, -CO-N(CI.₅ alkyl)-, -S-, -SO-, -SO₂-, -SO2-NH-, -SO₂-N(CI.₅ alkyl)-, -NH-SO2-, and -N(CI.₅ alkyl)-SO2-, and further wherein the carbocyclyl moiety in said -(C0-5 alkylene)-carbocyclyl and the heterocyclyl moiety in said -(C0-5 alkylene)-heterocyclyl are each optionally substituted with one or more groups independently selected from C1-5 alkyl, C2-5 alkenyl, C2-5 alkynyl, -OH, -O(Ci-5 alkyl), -O(Ci-5 alkylene)-OH, -O(Ci-5 alkylene)-O(Ci-5 alkyl), -SH, -S(Ci.₅ alkyl), -S(Ci.₅ alkylene)-SH, -S(Ci.₅ alkylene)-S(Ci.₅ alkyl), -NH₂, -NH(CI.₅ alkyl), -N(CI.₅ alkyl)(Ci-₅ alkyl), -NH-OH, -N(CI.₅ alkyl)-OH, -NH-O(CI.₅ alkyl), -N(CI.₅ alkyl)-O(Ci.₅ alkyl), halogen, C1.5 haloalkyl, -O-(Ci.₅ haloalkyl), -CF₃, -ON, -NO₂, -OHO, -CO-(Ci.₅ alkyl), -COOH, -CO-O-(Ci.₅ alkyl), -O-CO-(Ci.₅ alkyl), -CO-NH2, -CO-NH(CI-5 alkyl), -CO-N(CI.₅ alkyl)(Ci.₅ alkyl), -NH-CO-(CI.₅ alkyl), -N(CI.₅ alkyl)-CO-(Ci.₅ alkyl), -NH-CO-O-(CI-5 alkyl), -N(CI.₅ alkyl)-CO-O-(Ci.₅ alkyl), -O-CO-NH-(CI.₅ alkyl), -O-CO-N(CI.₅ alkyl)-(Ci.₅ alkyl), -SO2-NH2, -SO₂-NH(CI.5 alkyl), -SO₂-N(CI.₅ alkyl)(Ci.₅ alkyl), -NH-SO₂-(CI.₅ alkyl), -N(CI.₅ alkyl)-SO₂-(Ci.₅ alkyl), -SO2-(Ci-5 alkyl), -SO-(Ci-5 alkyl), cycloalkyl, and heterocycloalkyl.

Preferably, each R^s is independently selected from C1-5 alkyl, C2-5 alkenyl, C2-5 alkynyl, -(C0-3 alkylene)-OH, -(C0-3 alkylene)-O(Ci-5 alkyl), -(C0-3 alkylene)-O(Ci-5 alkylene)-OH, -(C0-3 alkylene)-O(Ci-5 alkylene)-O(Ci-5 alkyl), -(C0-3 alkylene)-SH, -(C0-3 alkylene)-S(Ci-5 alkyl), -(C0-3 alkylene)-S(Ci-5 alkylene)-SH, -(C0-3 alkylene)-S(Ci-5 alkylene)-S(Ci-5 alkyl), -(C0-3 alkylene)-NH2, -(C0-3 alkylene)-NH(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)(Ci-5 alkyl), -(Co-3 alkylene)-NH-OH, -(C0-3 alkylene)-N(Ci.₅ alkyl)-OH, -(C0-3 alkylene)-NH-O(Ci.₅ alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-O(Ci-5 alkyl), -(C0-3 alky lene)-halogen, -(C0-3 alkylene)-(Ci-5 haloalkyl), -(C0-3 alkylene)-O-(Ci-5 haloalkyl), -(C0-3 alkylene)-CN, -(C0-3 alkylene)-NO2, -(C0-3 alkylene)-CHO, -(C0-3 alkylene)-CO-(Ci-5 alkyl), -(C0-3 alkylene)-COOH, -(C0-3 alkylene)-CO-O-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO-(Ci-5 alkyl), -(C0-3 alkylene)-CO-NH2, -(C0-3 alkylene)-CO-NH(Ci-5 alkyl), -(C0-3 alkylene)-CO-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-CO-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-CO-(Ci-5 alkyl), -(C0-3 alkylene)-NH-CO-O-(Ci-5 alkyl), -(Co-3 alkylene)-N(Ci-5 alkyl)-CO-O-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO-NH-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO- N(CI-5 alkyl)-(Ci-5 alkyl), -(C0-3 alkylene)-SO2-NH2, -(C0-3 alkylene)-SO2-NH(Ci-5 alkyl), -(C0-3 alkylene)-SO2-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-SO2-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-SC>2-(Ci-5 alkyl), -(C0-3 alkylene)-SC>2-(Ci-5 alkyl), -(C0-3 alkylene)-S0-(Ci-5 alkyl), -(C0-5 alkylene)-carbocyclyl, and -(C0-5 alkylene)-heterocyclyl.

More preferably, each R^s is independently selected from C1-5 alkyl, C2-5 alkenyl, C2-5 alkynyl, -(C0-3 alkylene)-OH, -(C0-3 alkylene)-O(Ci-5 alkyl), -(C0-3 alkylene)-O(Ci-5 alkylene)-OH, -(C0-3 alkylene)-O(Ci-5 alkylene)-O(Ci-5 alkyl), -(C0-3 alkylene)-SH, -(C0-3 alkylene)-S(Ci-5 alkyl), -(C0-3 alkylene)-S(Ci-5 alkylene)-SH, -(C0-3 alkylene)-S(Ci-5 alkylene)-S(Ci-5 alkyl), -(C0-3 alkylene)-NH2, -(C0-3 alkylene)-NH(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)(Ci-₅ alkyl), -(C0-3 alkylene)-NH-OH, -(C0.3 alkylene)-N(Ci.₅ alkyl)-OH, -(C0.3 alkylene)-NH-O(Ci.₅ alkyl), -(C0-3 alky lene)-N (C1-5 alkyl)-O(Ci-5 alkyl), -(C0-3 alky lene)-halogen, -(C0-3 alkylene)-(Ci-5 haloalkyl), -(C0-3 alkylene)-O-(Ci-5 haloalkyl), -(C0-3 alkylene)-CN, -(C0-3 alkylene)-NO2, -(C0-3 alkylene)-CHO, -(C0-3 alkylene)-CO-(Ci-5 alkyl), -(C0-3 alkylene)-COOH, -(C0-3 alkylene)-CO-O-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO-(Ci-5 alkyl), -(C0-3 alkylene)-CO-NH2, -(C0-3 alkylene)-CO-NH(Ci-5 alkyl), -(C0-3 alkylene)-CO-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-CO-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-CO-(Ci-5 alkyl), -(C0-3 alkylene)-NH-CO-O-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-CO-O-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO-NH-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO- N(CI-5 alkyl)-(Ci-5 alkyl), -(C0-3 alkylene)-SO2-NH2, -(C0-3 alkylene)-SO2-NH(Ci-5 alkyl), -(C0-3 alkylene)-SO2-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-SO2-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-SO2-(Ci-5 alkyl), -(C0-3 alkylene)-SO2-(Ci-5 alkyl), and -(C0-3 alkylene)-SO-(Ci-5 alkyl).

Yet even more preferably, each R^s is independently selected from C1-5 alkyl, C2-5 alkenyl, C2-5 alkynyl, -OH, -SH, -NH₂, -NH-OH, halogen (e.g. , -F), C1.5 haloalkyl (e.g. , -CF₃), -ON, -NO₂, -CHO, -COOH, -CO-NH₂, and -SO2-NH2.

In formula (Id), n is selected from 0, 1, 2, 3, and 4. Preferably, n is selected from 0, 1 and 2. More preferably, n is selected from 0 and 1 . Even more preferably n is 0.

Then, if n = 0, the boronic acid-based glucose-binding moiety comprises a moiety of formula (Id'):

However, alternatively, n may also be 1. In this case, a preferred example of R^s is halogen, particularly -F, which is preferably attached in para-position with respect to the boronic acid group -B(-OH)2. Accordingly, the boronic acidbased glucose-binding moiety may comprise a moiety of formula (Id”):

Preferably, the boronic acid-based glucose-binding moiety comprises a moiety of formula (Id-a):

wherein R^s and n are as defined for formula (Id).

As mentioned before, in formula (Id-a), if n = 0, the boronic acid-based glucose-binding moiety comprises a moiety of formula (Id-a'):

If n = 1, and R^s = F, the boronic acid-based glucose-binding moiety preferably comprises a moiety of formula (ld-a”):

A particularly preferred monomer comprising the moiety of formula (Id) is an N-substituted acrylamide monomer according to formula (Id-b):

(Id-b) wherein R^s and n are as defined for formula (Id).

In particular embodiments, if n = 0, the monomer comprising a boronic acid-based glucose-binding moiety (Id) may be a monomer of formula (Id-b'):

(Id-b’)

If n = 1 , it is particularly preferred that R^s is -F. Accordingly, the monomer comprising a boronic acid-based glucose- binding moiety (Id) may preferably be a monomer of formula (Id-b”):

(ld-b”)

In an alternative embodiment of the present invention, the boronic acid-based glucose-binding moiety is comprised within (or is obtained by polymerization of) a monomer of formula (le-1) or (le-2):

In an alternative embodiment of the present invention, the boronic acid-based glucose-binding moiety comprises a moiety of formula (If):

Preferably, the moiety of formula (If) is comprised in the monomer according to formula (If-a):

wherein m is an integer from 1 to 10, preferably wherein m is selected from 2, 3, 4, 5 and 6, more preferably wherein m is 4.

In a preferred embodiment of the present invention, the boronic acid-based glucose-binding moiety comprises a moiety of formula (Ig):

In formula (Ig), each R is independently C1-5 alkyl, C2-5 alkenyl or C2-5 alkynyl. Preferably, each is independently C1-5 alkyl. More preferably, each R is C1-2 alkyl. Even more preferably, each R is methyl.

In formula (Ig), each R^s is independently selected from C1-5 alkyl, C2-5 alkenyl, C2-5 alkynyl, -(C0-3 alkylene)-OH, -(C0-3 alkylene)-O(Ci-5 alkyl), -(C0-3 alkylene)-O(Ci-5 alkylene)-OH, -(C0-3 alkylene)-O(Ci-5 alkylene)-O(Ci-5 alkyl), -(C0-3 alkylene)-SH, -(C0-3 alkylene)-S(Ci-5 alkyl), -(C0-3 alkylene)-S(Ci-5 alkylene)-SH, -(C0-3 alkylene)-S(Ci-5 alkylene)-S(Ci-5 alkyl), -(C0-3 alkylene)-NH2, -(C0-3 alkylene)-NH(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-OH, -(C0-3 alkylene)-N(Ci.₅ alkyl)-OH, -(C0-3 alkylene)-NH-O(Ci.₅ alkyl), -(C0-3 alky lene)-N (C1-5 alkyl)-O(Ci-5 alkyl), -(C0-3 alky lene)-halogen, -(C0-3 alkylene)-(Ci-5 haloalkyl), -(C0-3 alkylene)-O-(Ci-5 haloalkyl), -(C0-3 alkylene)-CN, -(C0-3 alkylene)-NO2, -(C0-3 alkylene)-CHO, -(C0-3 alkylene)-CO-(Ci-5 alkyl), -(C0-3 alkylene)-COOH, -(C0-3 alkylene)-CO-O-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO-(Ci-5 alkyl), -(C0-3 alkylene)-CO-NH2, -(C0-3 alkylene)-CO-NH(Ci-5 alkyl), -(C0-3 alkylene)-CO-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-CO-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-CO-(Ci-5 alkyl), -(C0-3 alkylene)-NH-CO-O-(Ci-5 alkyl), -(Co-3 alkylene)-N(Ci-5 alkyl)-C0-0-(Ci-5 alkyl), -(C0-3 alkylene)-0-C0-NH-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO- N(CI-5 alkyl)-(Ci-5 alkyl), -(C0-3 alkylene)-SO2-NH2, -(C0-3 alkylene)-SO2-NH(Ci-5 alkyl), -(C0-3 alkylene)-SO2-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-SO2-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-SO2-(Ci-5 alkyl), -(C0-3 alkylene)-SO2-(Ci-5 alkyl), -(C0-3 alkylene)-S0-(Ci-5 alkyl), -(C0-3 alkylene)-carbocyclyl, and -(C0-3 alkylene)-heterocyclyl, wherein the carbocyclyl moiety in said -(C0-3 alkylene)-carbocyclyl and the heterocyclyl moiety in said -(C0-3 alkylene)-heterocyclyl are each optionally substituted with one or more groups independently selected from C1-4 alkyl, halogen, -CN, -NO2, -OH, -O-(Ci-4 alkyl), -SH, -S-(Ci-4 alkyl), -NH2, -NH(CI-4 alkyl), -N(CI-4 alkyl)(Ci-₄ alkyl), -COOH, -COO(Ci.₄ alkyl), -CONH₂, -CONH(CI.₄ alkyl), -CON(CI.₄ alkyl)(Ci.₄ alkyl), -NHCO(CI.₄ alkyl) and -N(CI-4 alkyl)-CO(Ci-4 alkyl).

Preferably, each R^s is independently selected from C1-5 alkyl, C2-5 alkenyl, C2-5 alkynyl, -(C0-3 alkylene)-OH, -(C0-3 alkylene)-O(Ci-5 alkyl), -(C0-3 alkylene)-O(Ci-5 alkylene)-OH, -(C0-3 alkylene)-O(Ci-5 alkylene)-O(Ci-5 alkyl), -(C0-3 alkylene)-SH, -(C0-3 alkylene)-S(Ci-5 alkyl), -(C0-3 alkylene)-S(Ci-5 alkylene)-SH, -(C0-3 alkylene)-S(Ci-5 alkylene)-S(Ci-5 alkyl), -(C0-3 alkylene)-NH2, -(C0-3 alkylene)-NH(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-OH, -(C0-3 alkylene)-N(Ci.₅ alkyl)-OH, -(C0-3 alkylene)-NH-O(Ci.₅ alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-O(Ci-5 alkyl), -(C0-3 alky lene)-halogen, -(C0-3 alkylene)-(Ci-5 haloalkyl), -(C0-3 alkylene)-O-(Ci-5 haloalkyl), -(C0-3 alkylene)-CN, -(C0-3 alkylene)-NO2, -(C0-3 alkylene)-CHO, -(C0-3 alkylene)-CO-(Ci-5 alkyl), -(C0-3 alkylene)-COOH, -(C0-3 alkylene)-CO-O-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO-(Ci-5 alkyl), -(C0-3 alkylene)-CO-NH2, -(C0-3 alkylene)-CO-NH(Ci-5 alkyl), -(C0-3 alkylene)-CO-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-CO-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-CO-(Ci-5 alkyl), -(C0-3 alkylene)-NH-CO-O-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-CO-O-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO-NH-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO- N(CI-5 alkyl)-(Ci-5 alkyl), -(C0-3 alkylene)-SO2-NH2, -(C0-3 alkylene)-SO2-NH(Ci-5 alkyl), -(C0-3 alkylene)-SO2-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-SO2-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-SO2-(Ci-5 alkyl), -(C0-3 alkylene)-SO2-(Ci-5 alkyl), and -(C0-3 alkylene)-SO-(Ci-5 alkyl).

More preferably, each R^s is independently selected from C1-5 alkyl, C2-5 alkenyl, C2-5 alkynyl, -(C0-3 alkylene)-OH, -(C0-3 alkylene)-O(Ci-5 alkyl), -(C0-3 alkylene)-O(Ci-5 alkylene)-OH, -(C0-3 alkylene)-O(Ci-5 alkylene)-O(Ci-5 alkyl), -(C0-3 alkylene)-SH, -(C0-3 alkylene)-S(Ci-5 alkyl), -(C0-3 alkylene)-S(Ci-5 alkylene)-SH, -(C0-3 alkylene)-S(Ci-5 alkylene)-S(Ci-5 alkyl), -(C0-3 alkylene)-NH2, -(C0-3 alkylene)-NH(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)(Ci-₅ alkyl), -(C0-3 alkylene)-NH-OH, -(C0-3 alkylene)-N(Ci.₅ alkyl)-OH, -(C0-3 alkylene)-NH-O(Ci.₅ alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-O(Ci-5 alkyl), -(C0-3 alky lene)-halogen, -(C0-3 alkylene)-(Ci-5 haloalkyl), -(C0-3 alkylene)-O-(Ci-5 haloalkyl), -(C0-3 alkylene)-CN, -(C0-3 alkylene)-NO2, -(C0-3 alkylene)-CHO, -(C0-3 alkylene)-CO-(Ci-5 alkyl), -(C0-3 alkylene)-COOH, -(C0-3 alkylene)-CO-O-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO-(Ci-5 alkyl), -(C0-3 alkylene)-CO-NH2, -(C0-3 alkylene)-CO-NH(Ci-5 alkyl), -(C0-3 alkylene)-CO-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-CO-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-CO-(Ci-5 alkyl), -(C0-3 alkylene)-NH-CO-O-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-CO-O-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO-NH-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO- N(CI-₅ alkyl)-(Ci-₅ alkyl). Even more preferably, each R^s is independently selected from C1-5 alkyl, C2-5 alkenyl, C2-5 alkynyl, -(C0-3 alkylene)-OH, -(C0-3 alkylene)-O(Ci-5 alkyl), -(C0-3 alkylene)-O(Ci-5 alkylene)-OH, -(C0-3 alkylene)-O(Ci-5 alkylene)-O(Ci-5 alkyl), -(C0-3 alkylene)-SH, -(C0-3 alkylene)-S(Ci-5 alkyl), -(C0-3 alkylene)-S(Ci-5 alkylene)-SH, -(C0-3 alkylene)-S(Ci-5 alkylene)-S(Ci-5 alkyl), -(C0-3 alkylene)-NH2, -(C0-3 alkylene)-NH(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)(Ci-₅ alkyl), -(C0-3 alkylene)-NH-OH, -(C0.3 alkylene)-N(Ci.₅ alkyl)-OH, -(C0.3 alkylene)-NH-O(Ci.₅ alkyl), -(C0-3 alky lene)-N (C1-5 alkyl)-O(Ci-5 alkyl), -(C0-3 alky lene)-halogen, -(C0-3 alkylene)-(Ci-5 haloalkyl), -(C0-3 alkylene)-O-(Ci-5 haloalkyl), -(C0-3 alky lene)-CN, and -(C0-3 alkylene)-NO2.

Still more preferably, each R^s is independently selected from C1-5 alkyl, C2-5 alkenyl, C2-5 alkynyl, -OH, -O(Ci-5 alkyl), -O(Ci-5 alkylene)-OH, -O(Ci-5 alkylene)-O(Ci-5 alkyl), -SH, -S(Ci-5 alkyl), -S(Ci-5 alkylene)-SH, -S(Ci-5 alkylene)-S(Ci-₅ alkyl), -NH₂, -NH(Ci.₅ alkyl), -N(CI.₅ alkyl)(Ci_₅ alkyl), -NH-OH, -N(CI.₅ alkyl)-OH, -NH-O(CI.₅ alkyl), -N(CI-5 alkyl)-O(Ci-5 alkyl), -halogen, C1-5 haloalkyl, -O-(Ci-5 haloalkyl), -ON, and -NO2.

Again more preferably, each R^s is independently selected from -OH, -SH, -NH2, -NH-OH, -halogen, -ON, and -NO2.

In formula (Ig), n is 0, 1, 2 or 3. Preferably, n is 0 or 1. More preferably, n is 0. It will be understood that the variable n in formula (Ig) indicates the number of substituents R^s which are attached to the respective phenyl moiety. If n is 0, there are no substituents R^s, so that the corresponding phenyl ring is unsubstituted (i.e., carries hydrogen in place of R^s). Accordingly, it is preferred that the phenyl ring in the moiety of formula (Ig) is not substituted with R^s.

It will further be understood that the moiety of formula (Ig) may be attached to (or immobilized in) the polymer via any ring carbon atom of the respective phenyl ring, which is reflected by a bond that extends into the phenyl ring, whereby the wavy line (at one end of this bond) indicates the point of attachment of the moiety of formula (Ig).

The way in which the moiety of formula (Ig) is attached to the remainder of the polymer is not particularly limited, and any chemically feasible attachment is encompassed by the present invention. For example, the moiety of formula (Ig) may be attached via an amide linkage or an inversed amide linkage, e.g., via a group -NH-CO- or a group -CO-NH-. A particularly preferred attachment is illustrated in formula (Ig- 1) below; a further possible point of attachment is as shown in formula (Ig-b) below. Further examples of attachment points are apparent from the disclosure of the methods for preparing the polymers and the monomers used, including any of those described in the examples section.

In those embodiments where the boronic acid-based glucose-binding moiety comprises a moiety of formula (Ig), it is preferred that the polymer comprises a moiety of formula (Ig-a):

wherein R, R^s and n are as defined in formula (Ig).

However, in one embodiment of the present invention, the polymer comprises a moiety of formula (Ig-b):

wherein R, R^s and n are as defined in formula (Ig).

It will be appreciated by the skilled person that the moiety of formula (Ig) may be interconvertible with a form comprising a five membered ring formed through a bonding interaction between the nitrogen atom and the boron atom in the moiety of formula (Ig). Both forms may be present in an equilibrium, depending on the external conditions, e.g., the surrounding medium. In particular, in an aqueous medium, these forms may be interconverted by undergoing a ring-closing reaction or a corresponding ring-opening reaction, as illustrated in the following scheme:

The following definitions apply throughout the present specification and the claims, unless specifically indicated otherwise.

The term "hydrocarbon group” refers to a group consisting of carbon atoms and hydrogen atoms.

The term "alicyclic” is used in connection with cyclic groups and denotes that the corresponding cyclic group is non-aromatic.

As used herein, the term "alkyl” refers to a monovalent saturated acyclic (i.e., non-cyclic) hydrocarbon group which may be linear or branched. Accordingly, an "alkyl” group does not comprise any carbon-to-carbon double bond or any carbon-to-carbon triple bond. A “C1-5 alkyl” denotes an alkyl group having 1 to 5 carbon atoms. Preferred exemplary alkyl groups are methyl, ethyl, propyl (e.g., n-propyl or isopropyl), or butyl (e.g., n-butyl, isobutyl, sec-butyl, or tert-butyl). Unless defined otherwise, the term "alkyl” preferably refers to C1-4 alkyl, more preferably to methyl or ethyl, and even more preferably to methyl.

As used herein, the term "alkenyl” refers to a monovalent unsaturated acyclic hydrocarbon group which may be linear or branched and comprises one or more (e.g., one or two) carbon-to-carbon double bonds while it does not comprise any carbon-to-carbon triple bond. The term "C2-5 alkenyl” denotes an alkenyl group having 2 to 5 carbon atoms. Preferred exemplary alkenyl groups are ethenyl, propenyl (e.g., prop-1-en-1-yl, prop-1 -en-2-yl, or prop-2- en-1-yl), butenyl, butadienyl (e.g., buta-1 ,3-dien-1-yl or buta-1,3-dien-2-yl), pentenyl, or pentadienyl (e.g., isoprenyl). Unless defined otherwise, the term "alkenyl” preferably refers to C2-4 alkenyl.

As used herein, the term “alkynyl” refers to a monovalent unsaturated acyclic hydrocarbon group which may be linear or branched and comprises one or more (e.g., one or two) carbon-to-carbon triple bonds and optionally one or more (e.g., one or two) carbon-to-carbon double bonds. The term "C2-5 alkynyl” denotes an alkynyl group having 2 to 5 carbon atoms. Preferred exemplary alkynyl groups are ethynyl, propynyl (e.g., propargyl), or butynyl. Unless defined otherwise, the term "alkynyl” preferably refers to C2-4 alkynyl.

As used herein, the term "alkylene” refers to an alkanediyl group, i.e. a divalent saturated acyclic hydrocarbon group which may be linear or branched. A“CI-5 alkylene” denotes an alkylene group having 1 to 5 carbon atoms, and the term "C0-3 alkylene” indicates that a covalent bond (corresponding to the option "Co alkylene”) or a C1-3 alkylene is present. Preferred exemplary alkylene groups are methylene (-CH2-), ethylene (e.g., -CH2-CH2- or -CH(-CH3)-), propylene (e.g., -CH2-CH2-CH2-, -CH(-CH₂-CH₃)-, -CH₂-CH(-CH₃)-, or -CH(-CH₃)-CH₂-), or butylene (e.g., -CH₂- CH2-CH2-CH2-). Unless defined otherwise, the term "alkylene” preferably refers to C1-4 alkylene (including, in particular, linear C1-4 alkylene), more preferably to methylene or ethylene, and even more preferably to methylene.

As used herein, the term "alkenylene” refers to an alkenediyl group, i.e. a divalent unsaturated acyclic hydrocarbon group which may be linear or branched and comprises one or more (e.g., one or two) carbon-to-carbon double bonds while it does not comprise any carbon-to-carbon triple bond. A "C2-5 alkenylene” denotes an alkenylene group having 2 to 5 carbon atoms. Unless defined otherwise, the term "alkenylene” preferably refers to C2-4 alkenylene (including, in particular, linear C2-4 alkenylene).

As used herein, the term "alkynylene” refers to an alkynediyl group, i.e. a divalent unsaturated acyclic hydrocarbon group which may be linear or branched and comprises one or more (e.g., one or two) carbon-to-carbon triple bonds and optionally one or more (e.g., one or two) carbon-to-carbon double bonds. A "C2-5 alkynylene” denotes an alkynylene group having 2 to 5 carbon atoms. Unless defined otherwise, the term "alkynylene” preferably refers to C2-4 alkynylene (including, in particular, linear C2-4 alkynylene).

As used herein, the term "carbocyclyl” refers to a hydrocarbon ring group, including monocyclic rings as well as bridged ring, spiro ring and/or fused ring systems (which may be composed, e.g., of two or three rings), wherein said ring group may be saturated, partially unsaturated (i.e., unsaturated but not aromatic) or aromatic. Unless defined otherwise, "carbocyclyl” preferably refers to aryl, cycloalkyl or cycloalkenyl.

As used herein, the term “heterocyclyl” refers to a ring group, including monocyclic rings as well as bridged ring, spiro ring and/or fused ring systems (which may be composed, e.g., of two or three rings), wherein said ring group comprises one or more (such as, e.g., one, two, three, or four) ring heteroatoms independently selected from 0, S and N, and the remaining ring atoms are carbon atoms, wherein one or more S ring atoms (if present) and/or one or more N ring atoms (if present) may optionally be oxidized, wherein one or more carbon ring atoms may optionally be oxidized (i.e., to form an oxo group), and further wherein said ring group may be saturated, partially unsaturated (i.e., unsaturated but not aromatic) or aromatic. For example, each heteroatom-containing ring comprised in said ring group may contain one or two 0 atoms and/or one or two S atoms (which may optionally be oxidized) and/or one, two, three or four N atoms (which may optionally be oxidized), provided that the total number of heteroatoms in the corresponding heteroatom-containing ring is 1 to 4 and that there is at least one carbon ring atom (which may optionally be oxidized) in the corresponding heteroatom-containing ring. Unless defined otherwise, "heterocyclyl” preferably refers to heteroaryl, heterocycloalkyl or heterocycloalkenyl.

As used herein, the term "aryl” refers to an aromatic hydrocarbon ring group, including monocyclic aromatic rings as well as bridged ring and/or fused ring systems containing at least one aromatic ring (e.g., ring systems composed of two or three fused rings, wherein at least one of these fused rings is aromatic; or bridged ring systems composed of two or three rings, wherein at least one of these bridged rings is aromatic). If the aryl is a bridged and/or fused ring system which contains, besides one or more aromatic rings, at least one non-aromatic ring (e.g., a saturated ring or an unsaturated alicyclic ring), then one or more carbon ring atoms in each non-aromatic ring may optionally be oxidized (i.e., to form an oxo group). "Aryl” may, e.g., refer to phenyl, naphthyl, dialinyl (i.e., 1,2-dihydronaphthyl), tetralinyl (i.e., 1,2,3,4-tetrahydronaphthyl), indanyl, indenyl (e.g., 1 H-indenyl), anthracenyl, phenanthrenyl, 9H- fluorenyl, or azulenyl. Unless defined otherwise, an "aryl” preferably has 6 to 14 ring atoms, more preferably 6 to 10 ring atoms, even more preferably refers to phenyl or naphthyl, and most preferably refers to phenyl.

As used herein, the term "arylene” refers to an aryl group, as defined herein above, but having two points of attachment, i.e. a divalent aromatic hydrocarbon ring group, including monocyclic aromatic rings as well as bridged ring and/or fused ring systems containing at least one aromatic ring (e.g., ring systems composed of two or three fused rings, wherein at least one of these fused rings is aromatic; or bridged ring systems composed of two or three rings, wherein at least one of these bridged rings is aromatic). If the arylene is a bridged and/or fused ring system which contains, besides one or more aromatic rings, at least one non-aromatic ring (e.g., a saturated ring or an unsaturated alicyclic ring), then one or more carbon ring atoms in each non-aromatic ring may optionally be oxidized (i.e., to form an oxo group). "Arylene” may, e.g., refer to phenylene (e.g., phen-1 ,2-diyl, phen-1 ,3-diyl, or phen-1 ,4- diyl), naphthylene (e.g., naphthalen-1 ,2-diyl, naphthalen-1 , 3-diyl, naphthalen-1 , 4-diyl, naphthalen-1 ,5-diyl, naphthalen-1 , 6-diyl, naphthalen-1 , 7-diyl, naphthalen-2, 3-diyl, naphthalen-2, 5-diyl, naphthalen-2, 6-diyl, naphthalen- 2,7-diyl, or naphthalen-2, 8-diyl), 1,2-dihydronaphthylene, 1 ,2,3,4-tetrahydronaphthylene, indanylene, indenylene, anthracenylene, phenanthrenylene, 9H-fluorenylene, or azulenylene. Unless defined otherwise, an "arylene” preferably has 6 to 14 ring atoms, more preferably 6 to 10 ring atoms, even more preferably refers to phenylene or naphthylene, and most preferably refers to phenylene (particularly phen-1 , 4-diyl).

As used herein, the term "heteroaryl” refers to an aromatic ring group, including monocyclic aromatic rings as well as bridged ring and/or fused ring systems containing at least one aromatic ring (e.g., ring systems composed of two or three fused rings, wherein at least one of these fused rings is aromatic; or bridged ring systems composed of two or three rings, wherein at least one of these bridged rings is aromatic), wherein said aromatic ring group comprises one or more (such as, e.g., one, two, three, or four) ring heteroatoms independently selected from 0, S and N, and the remaining ring atoms are carbon atoms, wherein one or more S ring atoms (if present) and/or one or more N ring atoms (if present) may optionally be oxidized, and further wherein one or more carbon ring atoms may optionally be oxidized (i.e., to form an oxo group). For example, each heteroatom-containing ring comprised in said aromatic ring group may contain one or two 0 atoms and/or one or two S atoms (which may optionally be oxidized) and/or one, two, three or four N atoms (which may optionally be oxidized), provided that the total number of heteroatoms in the corresponding heteroatom-containing ring is 1 to 4 and that there is at least one carbon ring atom (which may optionally be oxidized) in the corresponding heteroatom-containing ring. "Heteroaryl” may, e.g., refer to thienyl (i.e., thiophenyl), benzo[b]thienyl, naphtho[2,3-b]thienyl, thianthrenyl, furyl (i.e., furanyl), benzofuranyl, isobenzofuranyl, chromanyl, chromenyl (e.g., 2H-1 -benzopyranyl or 4H-1 -benzopyranyl), isochromenyl (e.g., 1 H-2-benzopyranyl), chromonyl, xanthenyl, phenoxathiinyl, pyrrolyl (e.g., 1 H-pyrrolyl), imidazolyl, pyrazolyl, pyridyl (i.e., pyridinyl; e.g., 2-pyridyl, 3-pyridyl, or 4-pyridyl), pyrazinyl, pyrimidinyl, pyridazinyl, indolyl (e.g., 3H-indolyl), isoindolyl, indazolyl, indolizinyl, purinyl, quinolyl, isoquinolyl, phthalazinyl, naphthyridinyl, quinoxalinyl, cinnolinyl, pteridinyl, carbazolyl, p-carbolinyl, phenanthridinyl, acridinyl, perimidinyl, phenanthrolinyl (e.g., [1 , 10]phenanthrolinyl, [1,7]phenanthrolinyl, or [4,7]phenanthrolinyl), phenazinyl, thiazolyl, isothiazolyl, phenothiazinyl, oxazolyl, isoxazolyl, oxadiazolyl (e.g., 1 ,2,4-oxadiazolyl, 1 ,2,5-oxadiazolyl (i.e., furazanyl), or 1,3,4- oxadiazolyl), thiadiazolyl (e.g., 1,2,4-thiadiazolyl, 1 ,2,5-thiadiazolyl, or 1 ,3,4-thiadiazolyl), phenoxazinyl, pyrazolo[1 ,5-a]pyrimidinyl (e.g., pyrazolo[1 ,5-a]pyrimidin-3-yl), 1 ,2-benzoisoxazol-3-yl, benzothiazolyl, benzothiadiazolyl, benzoxazolyl, benzisoxazolyl, benzimidazolyl, benzo[b]thiophenyl (i.e., benzothienyl), triazolyl (e.g., 1 H-1,2,3-triazolyl, 2H-1 ,2,3-triazolyl, 1 H-1,2,4-triazolyl, or 4H-1 ,2,4-triazolyl), benzotriazolyl, 1 H-tetrazolyl, 2H-tetrazolyl, triazinyl (e.g., 1 ,2,3-triazinyl, 1 ,2,4-triazinyl, or 1 ,3,5-triazinyl), furo[2,3-c]pyridinyl, dihydrofuropyridinyl (e.g., 2,3-dihydrofuro[2,3-c]pyridinyl or 1,3-dihydrofuro[3,4-c]pyridinyl), imidazopyridinyl (e.g., imidazo[1 ,2- a]pyridinyl or imidazo[3,2-a]pyridinyl), quinazolinyl, thienopyridinyl, tetrahydrothienopyridinyl (e.g., 4, 5,6,7- tetrahydrothieno[3,2-c]pyridinyl), dibenzofuranyl, 1,3-benzodioxolyl, benzodioxanyl (e.g., 1,3-benzodioxanyl or 1 ,4-benzodioxanyl), or coumarinyl. Unless defined otherwise, the term "heteroaryl” preferably refers to a 5 to 14 membered (more preferably 5 to 10 membered) monocyclic ring or fused ring system comprising one or more (e.g., one, two, three or four) ring heteroatoms independently selected from 0, S and N, wherein one or more S ring atoms (if present) and/or one or more N ring atoms (if present) are optionally oxidized, and wherein one or more carbon ring atoms are optionally oxidized; even more preferably, a "heteroaryl” refers to a 5 or 6 membered monocyclic ring comprising one or more (e.g., one, two or three) ring heteroatoms independently selected from 0, S and N, wherein one or more S ring atoms (if present) and/or one or more N ring atoms (if present) are optionally oxidized, and wherein one or more carbon ring atoms are optionally oxidized.

As used herein, the term "heteroarylene” refers to a heteroaryl group, as defined herein above, but having two points of attachment, i.e. a divalent aromatic ring group, including monocyclic aromatic rings as well as bridged ring and/or fused ring systems containing at least one aromatic ring (e.g., ring systems composed of two or three fused rings, wherein at least one of these fused rings is aromatic; or bridged ring systems composed of two or three rings, wherein at least one of these bridged rings is aromatic), wherein said aromatic ring group comprises one or more (such as, e.g., one, two, three, or four) ring heteroatoms independently selected from 0, S and N, and the remaining ring atoms are carbon atoms, wherein one or more S ring atoms (if present) and/or one or more N ring atoms (if present) may optionally be oxidized, and further wherein one or more carbon ring atoms may optionally be oxidized (i.e., to form an oxo group). For example, each heteroatom-containing ring comprised in said aromatic ring group may contain one or two 0 atoms and/or one or two S atoms (which may optionally be oxidized) and/or one, two, three, or four N atoms (which may optionally be oxidized), provided that the total number of heteroatoms in the corresponding heteroatom-containing ring is 1 to 4 and that there is at least one carbon ring atom (which may optionally be oxidized) in the corresponding heteroatom-containing ring. "Heteroarylene” may, e.g., refer to thienylene (i.e., thiophenylene; e.g., thien-2,3-diyl, thien-2,4-diyl, or thien-2,5-diyl), benzo[b]thienylene, naphtho[2,3-b]thienylene, thianthrenylene, furylene (i.e., furanylene; e.g., furan-2,3-diyl, furan-2,4-diyl, or furan-2,5- diyl), benzofuranylene, isobenzofuranylene, chromanylene, chromenylene, isochromenylene, chromonylene, xanthenylene, phenoxathiinylene, pyrrolylene, imidazolylene, pyrazolylene, pyridylene (i.e., pyridinylene), pyrazinylene, pyrimidinylene, pyridazinylene, indolylene, isoindolylene, indazolylene, indolizinylene, purinylene, quinolylene, isoquinolylene, phthalazinylene, naphthyridinylene, quinoxalinylene, cinnolinylene, pteridinylene, carbazolylene, p-carbolinylene, phenanthridinylene, acridinylene, perimidinylene, phenanthrolinylene, phenazinylene, thiazolylene (e.g., thiazol-2,4-diyl, thiazol-2,5-diyl, or thiazol-4,5-diyl), isothiazolylene (e.g., isothiazol-3,4-diyl, isothiazol-3,5-diyl, or isothiazol-4,5-diyl), phenothiazinylene, oxazolylene (e.g., oxazol-2,4-diyl, oxazol-2,5-diyl, or oxazol-4,5-diyl), isoxazolylene (e.g., isoxazol-3,4-diyl, isoxazol-3,5-diyl, or isoxazol-4,5-diyl), oxadiazolylene (e.g., 1 ,2,4-oxadiazol-3,5-diyl, 1 ,2,5-oxadiazol-3,4-diyl, or 1 ,3,4-oxadiazol-2,5-diyl), thiadiazolylene (e.g., 1,2,4-thiadiazol-3,5-diyl, 1,2,5-thiadiazol-3,4-diyl, or 1,3,4-thiadiazol-2,5-diyl), phenoxazinylene, pyrazolo[1 ,5-a]pyrimidinylene, 1,2-benzoisoxazolylene, benzothiazolylene, benzothiadiazolylene, benzoxazolylene, benzisoxazolylene, benzimidazolylene, benzo[b]thiophenylene (i.e., benzothienylene), triazolylene (e.g., 1 H-1 ,2,3-triazolylene, 2H-1 ,2,3-triazolylene, 1 H-1,2,4-triazolylene, or 4H-1,2,4-triazolylene), benzotriazolylene, 1 H-tetrazolylene, 2H-tetrazolylene, triazinylene (e.g., 1 ,2,3-triazinylene, 1,2,4-triazinylene, or 1 ,3,5-triazinylene), furo[2,3-c]pyridinylene, dihydrofuropyridinylene (e.g., 2,3-dihydrofuro[2,3-c]pyridinylene or

1.3-dihydrofuro[3,4-c]pyridinylene), imidazopyridinylene (e.g., imidazo[1 ,2-a]pyridinylene or imidazo[3,2-a]pyridinylene), quinazolinylene, thienopyridinylene, tetrahydrothienopyridinylene (e.g., 4, 5,6,7- tetrahydrothieno[3,2-c]pyridinylene), dibenzofuranylene, 1,3-benzodioxolylene, benzodioxanylene (e.g.,

1.3-benzodioxanylene or 1 ,4-benzodioxanylene), or coumarinylene. Unless defined otherwise, the term "heteroarylene” preferably refers to a divalent 5 to 14 membered (more preferably 5 to 10 membered) monocyclic ring or fused ring system comprising one or more (e.g., one, two, three or four) ring heteroatoms independently selected from 0, S and N, wherein one or more S ring atoms (if present) and/or one or more N ring atoms (if present) are optionally oxidized, and wherein one or more carbon ring atoms are optionally oxidized; even more preferably, a "heteroarylene” refers to a divalent 5 or 6 membered monocyclic ring comprising one or more (e.g., one, two or three) ring heteroatoms independently selected from 0, S, and N, wherein one or more S ring atoms (if present) and/or one or more N ring atoms (if present) are optionally oxidized, and wherein one or more carbon ring atoms are optionally oxidized. A "heteroarylene”, including any of the specific heteroarylene groups described herein, may be attached through two carbon ring atoms, particularly through those two carbon ring atoms that have the greatest distance from one another (in terms of the number of ring atoms separating them by the shortest possible connection) within one single ring or within the entire ring system of the corresponding heteroarylene.

As used herein, the term "cycloalkyl” refers to a saturated hydrocarbon ring group, including monocyclic rings as well as bridged ring, spiro ring and/or fused ring systems (which may be composed, e.g., of two or three rings; such as, e.g., a fused ring system composed of two or three fused rings). "Cycloalkyl” may, e.g., refer to cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, decalinyl (i.e., decahydronaphthyl), or adamantyl. Unless defined otherwise, "cycloalkyl” preferably refers to a C3-11 cycloalkyl, and more preferably refers to a C3-7 cycloalkyl. A particularly preferred "cycloalkyl” is a monocyclic saturated hydrocarbon ring having 3 to 7 ring members (e.g., cyclopropyl or cyclohexyl).

As used herein, the term “heterocycloalkyl” refers to a saturated ring group, including monocyclic rings as well as bridged ring, spiro ring and/or fused ring systems (which may be composed, e.g., of two or three rings; such as, e.g., a fused ring system composed of two or three fused rings), wherein said ring group contains one or more (such as, e.g., one, two, three, or four) ring heteroatoms independently selected from 0, S and N, and the remaining ring atoms are carbon atoms, wherein one or more S ring atoms (if present) and/or one or more N ring atoms (if present) may optionally be oxidized, and further wherein one or more carbon ring atoms may optionally be oxidized (i.e., to form an oxo group). For example, each heteroatom-containing ring comprised in said saturated ring group may contain one or two 0 atoms and/or one or two S atoms (which may optionally be oxidized) and/or one, two, three or four N atoms (which may optionally be oxidized), provided that the total number of heteroatoms in the corresponding heteroatom-containing ring is 1 to 4 and that there is at least one carbon ring atom (which may optionally be oxidized) in the corresponding heteroatom-containing ring. "Heterocycloalkyl” may, e.g., refer to aziridinyl, azetidinyl, pyrrolidinyl, imidazolidinyl, pyrazolidinyl, piperidinyl, piperazinyl, azepanyl, diazepanyl (e.g., 1 ,4-diazepanyl), oxazolidinyl, isoxazolidinyl, thiazolidinyl, isothiazolidinyl, morpholinyl (e.g., morpholin-4-yl), thiomorpholinyl (e.g., thiomorpholin-4-yl), oxazepanyl, oxiranyl, oxetanyl, tetrahydrofuranyl, 1 ,3-dioxolanyl, tetrahydropyranyl, 1 ,4-dioxanyl, oxepanyl, thiiranyl, thietanyl, tetrahydrothiophenyl (i.e., thiolanyl), 1 ,3-dithiolanyl, thianyl, 1,1-dioxothianyl, thiepanyl, decahydroquinolinyl, decahydroisoquinolinyl, or 2-oxa-5-aza-bicyclo[2.2.1]hept- 5-yl. Unless defined otherwise, "heterocycloalkyl” preferably refers to a 3 to 11 membered saturated ring group, which is a monocyclic ring or a fused ring system (e.g., a fused ring system composed of two fused rings), wherein said ring group contains one or more (e.g., one, two, three, or four) ring heteroatoms independently selected from 0, S and N, wherein one or more S ring atoms (if present) and/or one or more N ring atoms (if present) are optionally oxidized, and wherein one or more carbon ring atoms are optionally oxidized; more preferably, "heterocycloalkyl” refers to a 5 to 7 membered saturated monocyclic ring group containing one or more (e.g., one, two, or three) ring heteroatoms independently selected from 0, S and N, wherein one or more S ring atoms (if present) and/or one or more N ring atoms (if present) are optionally oxidized, and wherein one or more carbon ring atoms are optionally oxidized. As used herein, the term “cycloalkenyl” refers to an unsaturated alicyclic (non-aromatic) hydrocarbon ring group, including monocyclic rings as well as bridged ring, spiro ring and/or fused ring systems (which may be composed, e.g., of two or three rings; such as, e.g., a fused ring system composed of two or three fused rings), wherein said hydrocarbon ring group comprises one or more (e.g., one or two) carbon-to-carbon double bonds and does not comprise any carbon-to-carbon triple bond. "Cycloalkenyl” may, e.g., refer to cyclopropenyl, cyclobutenyl, cyclopentenyl, cyclohexenyl, cyclohexadienyl, cycloheptenyl, or cycloheptadienyl. Unless defined otherwise, "cycloalkenyl” preferably refers to a C3-11 cycloalkenyl, and more preferably refers to a C3-7 cycloalkenyl. A particularly preferred "cycloalkenyl” is a monocyclic unsaturated alicyclic hydrocarbon ring having 3 to 7 ring members and containing one or more (e.g., one or two; preferably one) carbon-to-carbon double bonds.

As used herein, the term "heterocycloalkenyl” refers to an unsaturated alicyclic (non-aromatic) ring group, including monocyclic rings as well as bridged ring, spiro ring and/or fused ring systems (which may be composed, e.g., of two or three rings; such as, e.g., a fused ring system composed of two or three fused rings), wherein said ring group contains one or more (such as, e.g., one, two, three, or four) ring heteroatoms independently selected from 0, S and N, and the remaining ring atoms are carbon atoms, wherein one or more S ring atoms (if present) and/or one or more N ring atoms (if present) may optionally be oxidized, wherein one or more carbon ring atoms may optionally be oxidized (i.e., to form an oxo group), and further wherein said ring group comprises at least one double bond between adjacent ring atoms and does not comprise any triple bond between adjacent ring atoms. For example, each heteroatom-containing ring comprised in said unsaturated alicyclic ring group may contain one or two 0 atoms and/or one or two S atoms (which may optionally be oxidized) and/or one, two, three or four N atoms (which may optionally be oxidized), provided that the total number of heteroatoms in the corresponding heteroatom-containing ring is 1 to 4 and that there is at least one carbon ring atom (which may optionally be oxidized) in the corresponding heteroatom-containing ring. “Heterocycloalkenyl” may, e.g., refer to imidazolinyl (e.g., 2-imidazolinyl (i.e., 4,5- dihydro-1 H-imidazolyl), 3-imidazolinyl, or 4-imidazolinyl), tetrahydropyridinyl (e.g., 1 ,2,3,6-tetrahydropyridinyl), dihydropyridinyl (e.g., 1 ,2-dihydropyridinyl or 2,3-dihydropyridinyl), pyranyl (e.g., 2H-pyranyl or 4H-pyranyl), thiopyranyl (e.g., 2H-thiopyranyl or 4H-thiopyranyl), dihydropyranyl, dihydrofuranyl, dihydropyrazolyl, dihydropyrazinyl, dihydroisoindolyl, octahydroquinolinyl (e.g., 1 ,2,3,4,4a,5,6,7-octahydroquinolinyl), or octahydroisoquinolinyl (e.g., 1 ,2,3,4,5,6,7,8-octahydroisoquinolinyl). Unless defined otherwise, “heterocycloalkenyl” preferably refers to a 3 to 11 membered unsaturated alicyclic ring group, which is a monocyclic ring or a fused ring system (e.g., a fused ring system composed of two fused rings), wherein said ring group contains one or more (e.g., one, two, three, or four) ring heteroatoms independently selected from 0, S and N, wherein one or more S ring atoms (if present) and/or one or more N ring atoms (if present) are optionally oxidized, wherein one or more carbon ring atoms are optionally oxidized, and wherein said ring group comprises at least one double bond between adjacent ring atoms and does not comprise any triple bond between adjacent ring atoms; more preferably, "heterocycloalkenyl” refers to a 5 to 7 membered monocyclic unsaturated non-aromatic ring group containing one or more (e.g., one, two, or three) ring heteroatoms independently selected from 0, S and N, wherein one or more S ring atoms (if present) and/or one or more N ring atoms (if present) are optionally oxidized, wherein one or more carbon ring atoms are optionally oxidized, and wherein said ring group comprises at least one double bond between adjacent ring atoms and does not comprise any triple bond between adjacent ring atoms.

As used herein, the term "halogen” refers to fluoro (-F), chloro (-CI), bromo (-Br), or iodo (-1). The terms "halogen” and "halo” may be used interchangeably.

As used herein, the term "haloalkyl” refers to an alkyl group substituted with one or more (preferably 1 to 6, more preferably 1 to 3) halogen atoms which are selected independently from fluoro, chloro, bromo and iodo, and are preferably all fluoro atoms. It will be understood that the maximum number of halogen atoms is limited by the number of available attachment sites and, thus, depends on the number of carbon atoms comprised in the alkyl moiety of the haloalkyl group. "Haloalkyl” may, e.g., refer to -CF3, -CHF2, -CH2F, -CF2-CH3, -CH2-CF3, -CH2-CHF2, -CH2-CF2-CH3, -CH2-CF2-CF3, or -CH(CF₃)₂. A particularly preferred "haloalkyl” group is -CF3.

The terms "bond” and "covalent bond” are used herein synonymously, unless explicitly indicated otherwise or contradicted by context.

As used herein, the terms "optional”, "optionally” and "may” denote that the indicated feature may be present but can also be absent. Whenever the term "optional”, "optionally” or "may” is used, the present invention specifically relates to both possibilities, i.e., that the corresponding feature is present or, alternatively, that the corresponding feature is absent. For example, the expression "X is optionally substituted with Y” (or "X may be substituted with Y”) means that X is either substituted with Y or is unsubstituted. Likewise, if a component of a composition is indicated to be "optional”, the invention specifically relates to both possibilities, i.e., that the corresponding component is present (contained in the composition) or that the corresponding component is absent from the composition.

Various groups are referred to as being "optionally substituted” in this specification. Generally, these groups may carry one or more substituents, such as, e.g., one, two, three or four substituents. It will be understood that the maximum number of substituents is limited by the number of attachment sites available on the substituted moiety. Unless defined otherwise, the "optionally substituted” groups referred to in this specification carry preferably not more than two substituents and may, in particular, carry only one substituent. Moreover, unless defined otherwise, it is preferred that the optional substituents are absent, i.e. that the corresponding groups are unsubstituted.

A skilled person will appreciate that the substituent groups comprised in the compounds of the present invention may be attached to the remainder of the respective compound via a number of different positions of the corresponding specific substituent group. Unless defined otherwise, the preferred attachment positions for the various specific substituent groups are as illustrated in the examples. As used herein, unless explicitly indicated otherwise or contradicted by context, the terms "a”, "an” and "the” are used interchangeably with "one or more” and "at least one”.

It is to be understood that wherever numerical ranges are provided/disclosed herein, all values and subranges encompassed by the respective numerical range are meant to be encompassed within the scope of the invention. Accordingly, the present invention specifically and individually relates to each value that falls within a numerical range disclosed herein, including in particular each individual integer value that falls within a corresponding numerical range, as well as each subrange encompassed by a numerical range disclosed herein.

As used herein, the term "comprising” (or "comprise”, "comprises”, "contain”, "contains”, or "containing”), unless explicitly indicated otherwise or contradicted by context, has the meaning of "containing, inter alia”, i.e., "containing, among further optional elements, In addition thereto, this term also includes the narrower meanings of "consisting essentially of' and "consisting of'. For example, the term "A comprising B and C” has the meaning of "A containing, inter alia, B and C”, wherein A may contain further optional elements (e.g., "A containing B, C and D” would also be encompassed), but this term also includes the meaning of "A consisting essentially of B and C” and the meaning of "A consisting of B and C” (i.e., no other components than B and C are comprised in A).

As used herein, the term "subject” or "patient” refers to an animal, preferably a mammal (e.g., a human or a nonhuman mammal). Most preferably, the "subject” or "patient” is a human (e.g., a male human or a female human).

The measurement of the glucose concentration using the biosensor of the present invention typically requires a measurement of the polymer (or the polymeric hydrogel), particularly of the change in volume detected through the measurement of the change in length of the polymer/polymeric hydrogel. A corresponding measurement can be conducted using the method described in US 7,602,498 B2, which is incorporated by reference in its entirety. In particular, in order to measure the length of the polymeric hydrogel, the reflected interferometric spectrum from the hydrogel can be used to monitor changes in hydrogel length induced by varying glucose concentrations. The hydrogel is located at the tip of a cleaved single mode fiber. The relative length change of the hydrogel is monitored continuously against an initial absolute length L_g (t =

measurement. The hydrogel length is measured from the center of the cleave, along a straight vertical path relative to the cleave surface and to the tip of the hydrogel.

The reflected spectrum of the hydrogel approximates a sinewave with a DC-component, amplitude, period, and a phase term. The stepwise change of the refractive index between the silica fiber, hydrogel and fluid can be modelled as two weakly reflecting mirrors depicted by the boundary between the fiber and the hydrogel, T , and the hydrogel and surrounding fluid, r₂. The system represents a low finesse Fabry-Perot (FP) cavity. The model is shown in Figure 17.

The reflection coefficients are ry and r₂. The secondary and weakest reflection, at boundary r₂, interferes with the reflected light at boundary r- This interaction creates a sinusoidal interference pattern in the reflected intensity as a function of wavelength. The FP interferogram is described by:

where k = is the wavenumber of the light inside the hydrogel cavity and A is the wavelength of the light. An FP reflection spectrum from a hydrogel cavity of 39 nm long and n_g = 1.35 is shown in Figure 17. The absolute length of the hydrogel is determined by finding the period (free spectral range) of the sinus and length changes are determined by finding the phase-shift between spectra in time.

A specific exemplary sensor experimental setup which can be used in accordance with the present invention is described in Example 1.

The present invention relates to specific uses of the biosensor for measuring the concentration of glucose. Accordingly, the biosensor of the present invention is suitable for use in an in vivo diagnostic method. Said method preferably comprises a step of determining the glucose concentration in the blood of a subject (e.g., a human subject) using the biosensor of the invention, as described herein above. It is thus to be understood that the biosensor of the present invention is suitable for use in a method of determining the glucose concentration in the blood of a subject.

Preferably, the measurement can be performed on a continuous basis or repeated in certain time intervals, so that not only a single measurement point, which provides limited information on the state of the subject/patient, can be provided, but also a trend in blood glucose concentration over time or a series of measurements can be obtained, which are very important when monitoring the state of the patient over a longer time, for example when monitoring post-operative recovery of the patient or monitoring said patient in an intensive care setup. Such repeated or continued measurement may also be referred to as glucose monitoring. Hence, the present invention also relates to an in vivo method of glucose monitoring in a subject, the method comprising repeated measurements of the glucose concentration in the blood of a subject by using the biosensor of the present invention. Accordingly, the biosensor for measuring the concentration of glucose of the present invention is provided for use in an in vivo method of glucose monitoring.

The measurement of the blood glucose concentration is informative of conditions, diseases and disorders that are characterized by pathological glucose blood concentration, i.e. a concentration that is different from the concentration range considered to be normal. If the blood glucose concentration is lower than normal, typically lower than 70 mg/dL (or lower than 3.9 mmol/L), this may be referred to as hypoglycemia. If the blood glucose concentration is higher than normal, typically higher than 200 mg/dL (or higher than 11.1 mmol/L), this may be referred to as hyperglycemia. Such conditions can be determined or diagnosed by a direct measurement of the glucose concentration in the blood. Thus, the present invention further relates to a method of diagnosing hyperglycemia or hypoglycemia in a subject, the method comprising a step of measuring the blood glucose concentration using the biosensor of the present invention. Accordingly, the present invention provides a biosensor for measuring the concentration of glucose of the first embodiment of the present invention for use in an in vivo method of diagnosing hyperglycemia or hypoglycemia. In addition, the present invention also relates to use of the biosensor of the present invention in an in vitro method of diagnosing hyperglycemia or hypoglycemia, e.g., by measuring the glucose concentration in a blood sample obtained from a subject.

Thus, the present invention also provides a diagnostic method (particularly an in vitro diagnostic method), wherein the biosensor of the present invention is used, comprising a step of measuring the blood glucose concentration in a blood sample from a subject using said biosensor. Accordingly, the biosensor of the present invention may also be used outside of a patient's body for measuring the concentration of glucose in a sample obtained from the patient. Said method may also be referred to as an in vitro diagnostic method. In other words, the present invention provides the biosensor of the present invention for use in an in vitro diagnostic method. The method itself is not particularly limited, as long as it includes the necessary step of determining the glucose concentration in the blood sample. The measurement can be performed as described herein above, for example by measuring the change in volume of the polymer, occurring in a glucose concentration-dependent manner.

The measurements of the glucose concentration using the biosensor of the present invention are not limited to measurements in blood. Accordingly, the present invention generally relates to use of the biosensor of the invention for measuring the glucose concentration in a sample, including also a non-blood sample, such as, e.g., contents of a bioreactor, urine. Preferably, however, the sample is a blood sample (e.g., a whole blood sample, a serum sample, or a plasma sample).

The biosensor of the present invention can be configured for accessing the blood of a subject through an indwelling arterial catheter. As the sensor can be applied without disrupting the catheter's use, the sensor of the present invention requires no new catheters and displaces no other equipment.

As further provided herein, the present invention relates to the use of the polymer as provided by the present invention for the manufacture of a reagent or a biosensor for monitoring the glucose level in a subject. It is to be understood that changes in the properties of the polymer upon contact with glucose at different concentrations allow the measurements to be performed.

As discussed herein above, the biosensor of the present invention may also be used therapeutically, e.g., when incorporated in a glucose-concentration dependent release formulation. Thus, the present invention further provides a glucose-concentration-sensitive release formulation comprising the polymer as described herein. A corresponding glucose-sensitive release formulation may further comprise one or more pharmaceutically acceptable carriers, and an active substance/therapeutic agent (e.g., insulin) to be delivered in a glucose concentration-dependent manner.

Such formulations can be prepared by techniques known in the art, such as the techniques published in "Remington: The Science and Practice of Pharmacy”, Pharmaceutical Press, 22^nd edition. As the release into blood, upon measurement of the blood glucose concentration, is preferred, the formulations can be formulated as dosage forms for parenteral administration, such as intramuscular, intravenous, subcutaneous, intraarterial, or intracardial administration. Dosage forms for parenteral administration include, e.g., solutions, emulsions, suspensions, dispersions and powders and granules for reconstitution. Emulsions are a preferred dosage form for parenteral administration.

Accordingly, if the formulations are administered parenterally, then examples of such administration include one or more of: intravenously, intraarterially, intraperitoneally, intrathecally, intraventricularly, intraurethrally, intrasternally, intracardially, intracranially, intramuscularly or subcutaneously administering the formulations, and/or by using infusion techniques. For parenteral administration, the formulations comprising the polymers of the invention are best used in the form of a sterile aqueous solution which may contain other substances, for example, enough salts or saccharides to make the solution isotonic with blood. The aqueous solutions should be suitably buffered (preferably to a physiological pH), if necessary. The preparation of suitable parenteral formulations under sterile conditions is readily accomplished by standard pharmaceutical techniques.

The formulation of the present invention may also be formulated as a sustained release system, which may include semi permeable polymer matrices in the form of shaped articles, e.g., films or microcapsules. Sustained-release matrices may include, e.g., polylactides, copolymers of L-glutamic acid and gamma-ethyl-L-glutamate, poly(2- hydroxyethyl methacrylate), ethylene vinyl acetate, or poly-D-(— )-3-hydroxybutyric acid.

It is preferred that a condition/disease/disorder related to pathological blood concentration of glucose is to be treated. Accordingly, in one embodiment, the present invention relates to the biosensor of the present invention or to the glucose concentration-sensitive release formulations for use in the treatment of a condition/disease/disorder dependent of the blood glucose concentration. An example of such a condition is diabetes mellitus, for example type I diabetes. As known in the art, diabetes is typically treated by dosing the patient with insulin. Thus, the formulation of the present invention may further comprise insulin.

However, it is preferred that the biosensor of the present invention is not intended for therapeutic application and/or that the biosensor of the present invention does not comprise insulin.

Further examples and/or embodiments of the present invention are disclosed in the following numbered items. 1 . A biosensor for measuring the concentration of glucose, the biosensor comprising a polymer comprising:

• an inhibitor moiety, wherein said inhibitor moiety is immobilized in said polymer, and wherein said inhibitor moiety is capable of forming reversible crosslinks by binding to said boronic acid-based glucose-binding moiety; wherein in the absence of glucose, the polymer is crosslinked by a bond formed between the boronic acidbased glucose-binding moiety and the inhibitor moiety; and wherein in the presence of glucose, the boronic acid-based glucose-binding moiety binds to glucose, whereby the bond between the boronic acid-based glucose-binding moiety and the inhibitor moiety is broken, which results in a change of volume of the polymer; wherein the affinity of the inhibitor moiety to the boronic acid-based glucose-binding moiety is in the range of 0.4-fold to 20-fold affinity of said boronic acid-based glucose-binding moiety to glucose.

2. The biosensor of item 1, wherein the boronic acid-based glucose-binding moiety comprises a moiety of formula (la-1) and/or a moiety of formula (lb-1):

wherein each R^s is independently selected from C1-5 alkyl, C2-5 alkenyl, C2-5 alkynyl, -(C0-3 alkylene)-OH, -(C0-3 alkylene)-O(Ci-5 alkyl), -(C0-3 alkylene)-O(Ci-5 alkylene)-OH, -(C0-3 alkylene)-O(Ci-5 alkylene)-O(Ci-5 alkyl), -(C0-3 alkylene)-SH, -(C0-3 alkylene)-S(Ci-5 alkyl), -(C0-3 alkylene)-S(Ci-5 alkylene)-SH, -(C0-3 alkylene)-S(Ci-5 alkylene)-S(Ci-5 alkyl), -(C0-3 alkylene)-NH2, -(C0-3 alkylene)-NH(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-OH, -(C0-3 alkylene)-N(Ci-5 alkyl)-OH, -(C0-3 alkylene)-NH-O(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-O(Ci-5 alkyl), -(C0-3 alkylene)-halogen, -(C0-3 alkylene)-(Ci-5 haloalkyl), -(C0-3 alkylene)-O-(Ci-5 haloalkyl), -(C0-3 alkylene)-CN, -(C0-3 alkylene)-NO2, -(C0-3 alkylene)-CHO, -(C0-3 alkylene)-CO-(Ci-5 alkyl), -(C0-3 alkylene)-COOH, -(C0-3 alkylene)-CO-O-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO-(Ci-5 alkyl), -(C0-3 alkylene)-CO-NH2, -(C0-3 alkylene)-CO-NH(Ci-5 alkyl), -(C0-3 alkylene)-CO-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-CO-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-CO-(Ci-5 alkyl), -(C0-3 alkylene)-NH-CO-O-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-CO-O-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO-NH-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO-N(Ci-5 alkyl)-(Ci-5 alkyl), -(C0-3 alkylene)-SO2-NH2, -(C0-3 alkylene)-SO2-NH(Ci-5 alkyl), -(C0-3 alkvlene)-SO2-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-SO2-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-SO2-(Ci-5 alkyl), -(C0-3 alkylene)-SO2-(Ci-5 alkyl), -(C0-3 alkylene)-S0-(Ci-5 alkyl), -(C0-5 alkylene)-carbocyclyl, and -(C0-5 alkylene)-heterocyclyl, wherein one or more -CH2- units in the alkylene moiety in said -(C0-5 alkylene)-carbocyclyl and/or in the alkylene moiety in said -(C0-5 alkylene)-heterocyclyl are each optionally replaced by a group independently selected from -O-, -CO-, -CO-

0-, -0-C0-, -NH-, -N(CI-5 alkyl)-, -NH-CO-, -N(CI.₅ alkyl)-CO-, -CO-NH-, -CO-N(CI.₅ alkyl)-, -S-, -SO-, -S0₂-, -SO2-NH-, -SO₂-N(CI.₅ alkyl)-, -NH-SO2-, and -N(CI.₅ alkyl)-SO₂-, and further wherein the carbocyclyl moiety in said -(C0-5 alkylene)-carbocyclyl and the heterocyclyl moiety in said -(C0-5 alky lene)-heterocycly I are each optionally substituted with one or more groups independently selected from C1-5 alkyl, C2-5 alkenyl, C2-5 alkynyl, -OH, -0(Ci-5 alkyl), -0(Ci-5 alkylene)-OH, -0(Ci-5 alkylene)-0(Ci-5 alkyl), -SH, -S(Ci.₅ alkyl), -S(Ci.₅ alkylene)-SH, -S(Ci.₅ alkylene)-S(Ci.₅ alkyl), -NH₂, -NH(CI.₅ alkyl), -N(CI.₅ alkyl)(Ci.5 alkyl), -NH-OH, -N(CI.₅ alkyl)-OH, -NH-O(CI.₅ alkyl), -N(CI.₅ alkyl)-O(Ci_₅ alkyl), halogen, C1.5 haloalkyl, -O-(Ci.₅ haloalkyl), -CF₃, -ON, -N0₂, -OHO, -C0-(Ci.₅ alkyl), -COOH, -C0-0-(Ci.₅ alkyl), -0-C0-(Ci.5 alkyl), -CO-NH₂, -CO-NH(CI.₅ alkyl), -CO-N(CI.₅ alkyl)(Ci_₅ alkyl), -NH-CO-(CI.₅ alkyl), -N(CI-5 alkyl)-CO-(Ci.₅ alkyl), -NH-CO-O-(CI.₅ alkyl), -N(CI.₅ alkyl)-CO-O-(Ci.₅ alkyl), -O-CO-NH-(CI.₅ alkyl), -0-C0-N(CI.5 alkyl)-(Ci.₅ alkyl), -SO2-NH2, -SO₂-NH(CI.₅ alkyl), -SO₂-N(CI.₅ alkyl)(Ci.₅ alkyl), -NH-SO2-(CI-5 alkyl), -N(CI-5 alkyl)-SO2-(Ci-5 alkyl), -SO2-(Ci-5 alkyl), -S0-(Ci-5 alkyl), cycloalkyl, and heterocycloalkyl; and wherein n is independently 0, 1 , 2 or 3; and wherein the inhibitor moiety comprises a moiety of formula (Ila), a moiety of formula (lib) and/or a moiety of formula (lie):

The biosensor of item 1 or 2, wherein the boronic acid-based glucose-binding moiety comprises a moiety of formula (la-2) and/or a moiety of formula (lb-2):

wherein R^s and n are as defined in item 2; preferably wherein n is 0.

4. The biosensor of any one of items 1 to 3, wherein the inhibitor moiety comprises a moiety of formula (Ila)

(Ha).

5. The biosensor of item 4, wherein the boronic acid-based glucose-binding moiety and the inhibitor moiety are present in a molar ratio of from about 1 : 1 to about 1 :3, preferably in a molar ratio of from about 1 : 1 to about 1 :2.

6. The biosensor of any one of items 1 to 5, wherein in the presence of glucose, the boronic acid-based glucose-binding moiety binds to glucose, whereby the bond between the boronic acid-based glucose-binding moiety and the inhibitor moiety is broken, which results in a swelling of the polymer; preferably wherein the extent of swelling is substantially linearly proportional to the concentration of glucose.

7. The biosensor of any one of items 1 to 6, wherein the extent of the change of volume of the polymer in the presence of glucose is substantially independent of the pH value in the range from about pH 7.4 to about pH 7.6.

8. The biosensor of item 1, wherein the boronic acid-based glucose-binding moiety comprises a moiety of formula (Ic):

wherein:

R^L is selected from C4-8 alkylene, C4-8 alkenylene, C4-8 alkynylene, -(C0-2 alkylene)-arylene-(Co-2 alkylene)- and -(C0-2 alkylene)-heteroarylene-(Co-2 alkylene)-, wherein the arylene moiety in said -(C0-2 alkylene)- arylene-(Co-2 alkylene)- and the heteroarylene moiety in said -(C0-2 alkylene)-heteroarylene-(Co-2 alkylene)- are each optionally substituted with one or more R^s, and wherein one or more -CH2- units in said C4-8 alkylene, said C4-8 alkenylene or said C4-8 alkynylene are each optionally replaced by a group independently selected from -O-, -S-, -NH- and -N(CI-5 alkyl)-; each R^s is independently selected from C1-5 alkyl, C2-5 alkenyl, C2-5 alkynyl, -(C0-3 alkylene)-OH, -(C0-3 alkylene)-O(Ci-5 alkyl), -(C0-3 alkylene)-O(Ci-5 alkylene)-OH, -(C0-3 alkylene)-O(Ci-5 alkylene)-O(Ci-5 alkyl), -(C0-3 alkylene)-SH, -(C0-3 alkylene)-S(Ci-5 alkyl), -(C0-3 alkylene)-S(Ci-5 alkylene)-SH, -(C0-3 alkylene)-S(Ci-5 alkylene)-S(Ci-5 alkyl), -(C0-3 alkylene)-NH2, -(C0-3 alkylene)-NH(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-OH, -(C0-3 alkylene)-N(Ci-5 alkyl)-OH, -(C0-3 alkylene)-NH-O(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-O(Ci-5 alkyl), -(C0-3 alkylene)-halogen, -(C0-3 alkylene)-(Ci-5 haloalkyl), -(C0-3 alkylene)-O-(Ci-5 haloalkyl), -(C0-3 alkylene)-CN, -(C0-3 alkylene)-NO2, -(C0-3 alkylene)-CHO, -(C0-3 alkylene)-CO-(Ci-5 alkyl), -(C0-3 alkylene)-COOH, -(C0-3 alkylene)-CO-O-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO-(Ci-5 alkyl), -(C0-3 alkylene)-CO-NH2, -(C0-3 alkylene)-CO-NH(Ci-5 alkyl), -(C0-3 alkylene)-CO-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-CO-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-CO-(Ci-5 alkyl), -(C0-3 alkylene)-NH-CO-O-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-CO-O-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO-NH-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO-N(Ci-5 alkyl)-(Ci-5 alkyl), -(C0-3 alkylene)-SO2-NH2, -(C0-3 alkylene)-SO2-NH(Ci-5 alkyl), -(C0-3 alkylene)-SO2-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-SO2-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-SO2-(Ci-5 alkyl), -(C0-3 alkylene)-SO2-(Ci-5 alkyl), -(C0-3 alkylene)-SO-(Ci-5 alkyl), -(C0-5 alkylene)-carbocyclyl, and -(C0-5 alkylene)-heterocyclyl, wherein one or more -CH2- units in the alkylene moiety in said -(C0-5 alkylene)-carbocyclyl and/or in the alkylene moiety in said -(C0-5 alky lene)-heterocycly I are each optionally replaced by a group independently selected from -O-, -CO-, -CO-O-, -O-CO-, -NH-, -N(CI.₅ alkyl)-, -NH-CO-, -N(CI.₅ alkyl)-CO-, -CO-NH-, -CO-N(CI.₅ alkyl)-, -S-, -SO-, -SO₂-, -SO2-NH-, -SO₂-N(CI.₅ alkyl)-, -NH-SO2-, and -N(CI.₅ alkyl)-SO₂-, and further wherein the carbocyclyl moiety in said -(C0-5 alkylene)-carbocyclyl and the heterocyclyl moiety in said -(C0-5 alky lene)-heterocycly I are each optionally substituted with one or more groups independently selected from C1-5 alkyl, C2-5 alkenyl, C2-5 alkynyl, -OH, -O(Ci-5 alkyl), -O(Ci-5 alkylene)-OH, -O(Ci-5 alkylene)-O(Ci-5 alkyl), -SH, -S(Ci.₅ alkyl), -S(Ci.₅ alkylene)-SH, -S(Ci.₅ alkylene)-S(Ci.₅ alkyl), -NH₂, -NH(CI.₅ alkyl), -N(CI.₅ alkyl)(Ci-₅ alkyl), -NH-OH, -N(CI_₅ alkyl)-OH, -NH-O(CI.₅ alkyl), -N(CI_₅ alkyl)-O(Ci.₅ alkyl), halogen, C1.5 haloalkyl, -O-(Ci_₅ haloalkyl), -CF₃, -CN, -NO₂, -CHO, -CO-(Ci.₅ alkyl), -COOH, -CO-O-(Ci.₅ alkyl), -O-CO-(Ci-₅ alkyl), -CO-NH₂, -CO-NH(CI.₅ alkyl), -CO-N(CI.₅ alkyl)(Ci_₅ alkyl), -NH-CO-(CI.₅ alkyl), -N(CI.5 alkyl)-CO-(Ci_₅ alkyl), -NH-CO-O-(CI.₅ alkyl), -N(CI_₅ alkyl)-CO-O-(Ci_₅ alkyl), -O-CO-NH-(CI.₅ alkyl), -O-CO-N(CI-₅ alkyl)-(Ci_₅ alkyl), -SO2-NH2, -SO₂-NH(CI.₅ alkyl), -SO₂-N(CI.₅ alkyl)(Ci_₅ alkyl), -NH-SO₂-(CI-5 alkyl), -N(CI-5 alkyl)-SO₂-(Ci-5 alkyl), -SO₂-(Ci-5 alkyl), -SO-(Ci-5 alkyl), cycloalkyl, and heterocycloalkyl; and n' and n” are each independently selected from 0, 1, 2, 3, and 4. The biosensor of item 8, wherein the boronic acid-based glucose-binding moiety comprises a moiety of formula (lc-1):

wherein:

R^L, R^s, n' and n” are as defined in item 8;

R¹ is a group -CONH-CH2CH2-(O-CH2CH2)_m-, wherein m is an integer in the range from 1 to 10, or a group -CH2-arylene; and wherein R¹ is attached via its terminal -CH₂- group to the nitrogen atom in formula (lc-1); and

R² is a group -CH₂-CONH-(CH2CH₂O)p-(Ci.5 alkyl), C1-5 alkyl, -(C0-3 alkylene)-aryl, or -(C0-3 alkylene)- heteroaryl, wherein p is an integer in the range from 1 to 10, wherein the aryl in said -(C0-3 alkylene)-aryl and the heteroaryl in said -(C0-3 alkylene)-heteroaryl are each optionally substituted with one or more R^s; wherein it is preferred that n' and n” are each 0, and/or that R^L is -(CH₂)6-. The biosensor of item 8 or 9, wherein the inhibitor moiety comprises a moiety of the following formula (lie):

(He), and wherein the boronic acid-based glucose-binding moiety and the inhibitor moiety are present in a molar ratio of about 1 :1. The biosensor of item 8 or 9, wherein the inhibitor moiety comprises a moiety of the following formula (lib):

(Hb), and wherein the boronic acid-based glucose-binding moiety and the inhibitor moiety are present in a molar ratio of from about 2:1 to about 1 :3; preferably wherein the boronic acid-based glucose-binding moiety and the inhibitor moiety are present in a molar ratio of from about 1 : 1 to about 1 :3, more preferably wherein the boronic acid-based glucose-binding moiety and the inhibitor moiety are present in a molar ratio of 1 :1 to 1 :2, even more preferably wherein the boronic acid-based glucose-binding moiety and the inhibitor moiety are present in a molar ratio of about 1 :2. The biosensor of any one of items 1 to 11 , wherein the polymer Is a polymeric hydrogel. The biosensor of any one of items 1 to 12, wherein the polymer is obtainable in a polymerization reaction of a composition comprising:

(ii) an acrylamide monomer comprising the inhibitor moiety. The biosensor of item 13, wherein the composition used in the polymerization reaction further comprises: (ill) an acrylamide monomer free of boronic-acid moiety and free of inhibitor moiety, and

(iv) a crosslinker acrylamide monomer; wherein it is preferred that:

- the acrylamide monomer (I) constitutes between 6 and 10 mol% of the acrylamide-based components in said composition, wherein the acrylamide monomers (I) and (ii) are present in a molar ratio of about 1 :1 ; and/or

- the acrylamide monomer (ill) constitutes between 60 and 84 mol% of the acrylamide-based components in said composition; and/or

- the crosslinker acrylamide monomer (iv) constitutes between 0.1 and 4 mol% of the acrylamide-based components in said composition; and/or

- the acrylamide monomer (I) is selected from

; and/or - the acrylamide monomer (ii) is selected from

, wherein q is an integer from 0 to 10, preferably wherein q is an integer from 0 to 5, more preferably wherein q is an integer from 0 to 2, even more preferably wherein q is 0; and/or

- the acrylamide monomer (ill) is selected from:

an integer from 2 to 5, more preferably wherein q is 2 or 5; and/or

- the crosslinker acrylamide monomer (iv) is selected from:

wherein q is an integer from 0 to 10, preferably wherein q is an integer from 2 to 5, more preferably wherein q is 2 or 5. 15. The biosensor of any one of items 1 to 14 for use in an in vivo diagnostic method.

16. The biosensor of any one of items 1 to 14 for use in an in vivo method of glucose monitoring.

17. The biosensor for use according to item 16, wherein the glucose monitoring is performed on a subject that is under intensive care and/or that is unconscious.

18. The biosensor of any one of items 1 to 14 for use in an in vivo method of diagnosing hyperglycemia or hypoglycemia.

19. Use of the biosensor of any one of items 1 to 14 in an in vitro diagnostic method.

20. Use of the biosensor of any one of items 1 to 14 for measuring the glucose concentration in a sample.

21. Use of the biosensor of any one of items 1 to 14 in an in vitro method of diagnosing hyperglycemia or hypoglycemia.

22. The polymer as described in any one of items 1 to 14.

The invention will be illustrated by the following examples, which serve solely illustrative purposes and are not to be construed as limiting the scope of the claims.

EXAMPLES

Example 1

Materials and methods

SORPEGS, (D-Gluconoheptonic amide-PEG6-acrylamide) FURPEGS (2-[2-[2-[2-(2-Acryloylamidoethoxy)- ethoxy]ethoxy]ethoxy]ethoxy]ethyl-alpha-D-mannofuranoside), GLUPEGS (2-[2-[2-[2-(2-Acryloylamidoethoxy)- ethoxy]ethoxy]ethoxy]ethoxy]ethyl-beta-D-glucopyranoside) MANPEGS (2-[2-[2-[2-(2-Acryloylamidoethoxy)- ethoxy]ethoxy]ethoxy]ethoxy]ethyl-alpha-D-mannopyranoside), MANPEG2 (2-[2-(2-

Acryloylamidoethoxy)ethoxy]ethyl-alpha-D-mannopyranoside), MAN (2-Acryloylamidoethyl-alpha-D- mannopyranoside), BIS1 ((2-(20-(2-boronobenzyl)-18-oxo-27-(16-oxo-3,6,9,12,15-pentaoxaoctadec-17-en-1-yl)- 2,5,8, 11,14-pentaoxa-17,20,27-triazaoctacosan-28-yl)phenyl)boronic acid), BIS2 ((2-(2-(4-(2-(2-boronobenzyl)-4- oxo-8, 11 , 14, 17, 20-pentaoxa-2, 5-d i azahen icosy I) benzyl )- 18-oxo-5,8, 11 , 14, 17-pentaoxa-2-azaicos-19-en-1 - yl)phenyl)boronic acid), and BIS3 ((2-(2-(6-((2-boronobenzyl)(pyren-1-ylmethyl)amino)hexyl)-18-oxo-5,8, 11 , 14,17- pentaoxa-2-azaicos-19-en-1-yl)phenyl)boronic acid) were synthesized according to the procedures given below. BOB, was purchased from Combi-Blocks Inc. and used without further purification. TRIS (N-[Tris(hydroxymethyl)methyl]acrylamide), GEMA (Glycosyloxyethyl methacrylate)and GLY (Glycerol monomethacrylate) were purchased from Sigma-Aldrich and used without further purification.

Acrylamide, N-Hydroxyethyl acrylamide (HEAA), N-(Hydroxymethyl)acrylamide solution (HMAA), methylene bis acrylamide, 1 -hydroxycyclohexyl phenyl ketone, 3-(trimethoxysilyl)propyl methacrylate, squalane were purchased from Sigma-Aldrich. Dimethyl sulfoxide was purchased from Sigma-Aldrich.

0.01 M PBS pH 7.4 (0.132 M NaCI) was prepared in-house, di-sodium hydrogen phosphate was purchased from Alfa Aesar, sodium phosphate monobasic monohydrate was purchased from Sigma-Aldrich and sodium chloride was purchased from Sigma-Aldrich.

Alizarin Red S (ARS) was purchased from Sigma-Aldrich. a-D-glucose, methyl p-D-glucopyranoside, methyl o-D-mannopyranoside and sorbitol were purchased from Sigma Aldrich

Methyl o-D-mannofuranoside was purchased from Synthose Inc.

D,L-homocysteine thiolactone acrylamide was purchased from Specific Polymers. Ethanolamine was purchased from Sigma-Aldrich.

For the analysis using the LC/MS method, the following methods were applied:

Method 1: C18, 5 to 95 % AcCN in H2O in 4 followed by 3min 95% AcCN in H2O

Method 2: C18, 20-50 % AcCN in H2O in 10min

Method 3: C18, 5-15 % AcCN in H2O in 4 min followed by 3min 15% AcCN in H2O

Synthesis of MANPEGS (2-[2-[2-[2-(2-Acryloylamidoethoxy)-ethoxy]ethoxy]ethoxy]ethoxy]ethyl-alpha-D- mannopyranoside)

Compound 2

Hexaethylenglycol (10 g, 34.00 mmol) was added to an oven-dried round bottom flask and the flask was purged with argon. Anhydrous THF (70 mL), pyridine (5.2 mL, 64 mmol) and p-TsCI (5.75 mg, 0.03 mmol) were added and the reaction was allowed to stir for 2.5 hours. The solution was concentrated under reduced pressure and diluted with DCM (20 mL), washed with 1 M NaOH (25 mL), 1 M HOI (25 mL) and brine (25 mL). The organic layers were then combined, dried over magnesium sulfate, and concentrated under reduced pressure to produce a yellow oil. The oil was diluted with DMF (70 mL), and NaNa (3 equiv., 6.63 g, 102 mmol) was added and the reaction mixture was heated at 65 °C overnight. The reaction mixture was concentrated under reduced pressure and the residue was diluted with DCM, washed with 1 M NaOH (25 mL), 1 M HOI (25 mL), and brine (25 mL). The organic layers were combined, dried over magnesium sulfate and concentrated to produce a yellow oil. Purification by silica gel column chromatography (gradient: EtOAC 100% to EtCAc/MeCH=90/10) afforded 3.4 g (11 mmol) of compound 2 as a yellow oil (32%, 2 steps).

Compound 4

To a solution of compound 2 (600 mg, 1.95 mmol) and 2,3,4,6-tetra-O-benzoyl-a-D-mannopyranosyl trichloroacetimidate 3 (1.9 g, 2.6 mmol) in anhydrous DCM (25 mL) cooled to -20°C was added BORON TRI FLUORIDE DIETHYL ETHERATE (0.250 mL, 1.98 mmol) and the mixture was stirred at 0°C. After 2.5 h the reaction mixture was quenched with EtaN (1 mL) and the the solvent removed under reduced pressure. The residue was purified by silica gel column chromatography (gradient: EtOAc/PE=50%/50% to EtOAc 100) to afford compound 4 (973 mg, 56%) as a yellow oil.

Compound 5

Compound 4 (188 mg, 0.21 mmol) was dissolved in EtOH (5 mL) and, P/C (10 wt) (cat) was added and the resulting suspension was stirred under H2 at room temperature for 2 hours. The catalyst was removed by filtration over celite and the filtrate was concentrated under reduced pressure to give crude compound 5 as a colourless oil (141.7 mg, 78%). Compound 6

Compound 5 (130.5 mg, 0.15 mmol) was dissolved in anhydrous DCM (5 mL), the solution was cooled at 0°C and EtaN (79 pL, 0.57 mmol) followed by acryloyl chloride (14 pL, 0.17 mmol) was added. The reaction mixture was stirred at room temperature for 3 hours, LCMS showed 25% of the SM was remaining, and therefore another 0.3 equiv. of acryloyl chloride was added and the reaction was stirred at room temperature overnight. The reaction mixture was diluted with DCM and washed with water, 1 M HCI, NaHCOa and brine. The organic phase was dried over MgSO4 and concentrated under reduced pressure. The crude product was purified bv silica gel column chromatography (gradient: EtOAc/MeOH = 1/0 to 97/3) to afford compound 6 (73 mg, 53%) as a colourless oil.

Compound 7

To a solution of compound 6 (0.250 g) in methanol (8 mL) was added lithium hydroxide (1.6 mL, 1.6 mmol) and the resulting reaction mixture was stirred at room temperature for 2 hours. The reaction mixture was directly loaded onto as C18 flash column and the product was eluted using a gradient of 2 to 30% MeCN in water. Product containing fractions were collected and concentrated under reduced pressure. The residue was dissolved in water (8mL), Dowex H⁺ resin (2-3eq, 0.7ml) was added and the mixture was agitated for 4 minutes, then the resin removed by filtration and the filtrate was lyophilized to obtain compound 7 (85 mg, 73% Yield).

NMR spectra for the final product are shown in Figure 18. Further analytical data:

RT 2.72 min (Method 1); m/z 498.4 (M+H)⁺ (ESI⁺);

¹H NMR (D₂0, 400 MHZ): 6.28 (dd, J = 17.0 Hz, J = 10.0 Hz, 1 H), 6.19 (d, J = 17.0 Hz,1 H), 5.76 (d, J = 10.0 Hz,1 H), 4.87 (s, 1 H), 3.95 (m, 1 H), 3.83 (m, 2H), 3.80 (m, 1 H), 3.78-3.60 (m, 26H), 3.47 (dd, J = 4.5 Hz, J = 4.5 Hz, 1 H)

Synthesis of MANPEG2 (2-[2-(2-Acryloylamidoethoxy)ethoxy]ethyl-alpha-D-mannopyranoside)

Compound 4

To a solution of compound 2 (455 mg, 1.48 mmol) and 2,3,4,6-tetra-O-benzoyl-a-D-mannopyranosyl trichloroacetimidate 3 (1 .45 g, 1 .69 mmol) in anhydrous DCM (25 mL) cooled to -20°C was added boron trifluoride diethyl etherate (0.50 mL, 1.90 mmol) and the mixture was stirred at 0°C. After 1 h the reaction mixture was quenched with EtaN (1 mL) and the solvent was removed under reduced pressure. The residue was purified by silica gel column chromatography (gradient: MeOH/DCM = 0 to 2%) to afford compound 4 (1.1g, 84%) as a yellow oil.

Compound 5

Compound 4 (0.53g, 0.7 mmol) was dissolved in MeOH (10 mL) and, Pd/C (100mg, 10 wt%) was added and the resulting suspension was stirred under H2 at room temperature for 2 hours. The catalyst was removed by filtration over celite and the filtrate was concentrated under reduced pressure to give crude compound 5 as a colourless oil.

Compound 6

Compound 5 (740 mg, 1.02 mmol) was dissolved in anhydrous DCM (8 mL), the solution was cooled at 0°C and EtaN (0.85mL, 6.1 mmol) followed by acryloyl chloride (0.13 mL, 1.53 mmol) was added. The reaction mixture was stirred at room temperature for 14 hours. The reaction mixture was diluted with DCM and washed with water, 1 M HCI, NaHCOa and brine. The organic phase was dried over MgSO4 and concentrated under reduced pressure. The crude product was purified bv silica gel column chromatography (gradient: EtOAc/MeOH = 1/0 to 97/3) to afford compound 6 (498 mg, 61 %) as a colourless oil.

Compound 7

To a solution of compound 6 (0.250 g) in methanol (8 mL) was added lithium hydroxide (1.6 mL, 1.6 mmol) and the resulting reaction mixture was stirred at room temperature for 2 hours. The reaction mixture was directly loaded onto as C18 flash column and the product was eluted using a gradient of 2 to 30% MeCN in water. Productcontaining fractions were collected and concentrated under reduced pressure. The residue was dissolved in water (8mL), Dowex H⁺ resin (2-3eq, 0.7ml) was added and the mixture was agitated for 4 minutes, then the resin removed by filtration and the filtrate was lyophilised to obtain compound 7 (85 mg, 73% Yield).

NMR spectra for the final product is shown in Figure 19. Further analytical data:

RT 2.34 min (Method 2); m/z 366.2 (M+H)⁺ (ESI⁺);

¹H NMR (D₂0, 400 MHz): 6.27 (dd, J = 17.2 Hz, J = 10.0 Hz, 1 H), 6.18 (dd, J = 17.2 Hz, J = 1.5 Hz, 1 H), 5.76 (dd, J = 10.0 Hz, J = 1.5 Hz, 1 H), 4.87 (s, 1 H), 3.94 (m, 1 H), 3.86 (m, 2H), 3.81 (m, 1 H), 3.76 (m, 1 H) 3.73-3.60 (m, 12H), 3.46 (dd, J = 4.5 Hz, J = 4.5 Hz, 1 H)

Synthesis of BIS1

3

Compound 3 To a solution of IT1PEG5NH2 (5 g, 19.89 mmol) and triethylamine (5.5 mL, 39.8 mmol) in dry DCM (50 mL) at -78°C was added chloroacetyl chloride (2.4 mL, 29.8 mL) dropwise. The reaction mixture was allowed to warm to room temperature and stirred for a further 0.5 hours. LCMS analysis indicated the reaction was complete. Filtered through cotton wool and the filtrate was concentrated under reduced pressure to give crude compound 3, which was used without further purification.

Compound 10

A mixture of compound 3 (6.52 g, 19.9 mmol), N-Boc-1,6-diaminohexane (6.552 g, 30.29 mmol), sodium iodide (1.49 g, 9.94 mmol) and triethylamine (5.54 mL, 39.7 mmol) in MeCN (80 mL) was warmed to 45°C for 48 hours. LCMS analysis indicated the reaction was complete. The mixture was filtered through cotton wool then concentrated under reduced pressure. The residue was partitioned between ethyl acetate and water, and the aqueous phase was concentrated to afford 10 of suitable purity for the next step.

Compound 11

To a mixture of compound 10 (10.1 g, 19.9 mmol) and potassium carbonate (2.75 g, 19.9 mmol) in 2:1 MeCN/FW) (60 mL) was added Fmoc-OSu (6.71 g, 19.9 mmol) and the mixture stirred rapidly at room temperature for 3 hours. The mixture was filtered through cotton wool and the solvents removed under reduced pressure. The residue was taken up in DCM, filtered and purified by column chromatography (80 g silica gel, 0 to 5% MeOH in DCM) to afford compound 11 as an orange oil (5.496 g, 38% over three steps).

Compound 12

To a solution of compound 11 (150 mg, 0.205 mmol) in DCM (3 mL) was added TFA (62 uL, 0.82 mmol) and the mixture was stirred at room temperature for 1 hour. LCMS analysis indicated the reaction was complete. The solvents were removed under reduced pressure and the residue taken up in water and lyophilised to afford compound 12 as an orange oil (210 mg, quant, with some excess TFA).

13

Compound 13

To a mixture of NH2-PEG5-OH (1.400 g, 5.90 mmol) and sodium bicarbonate (790 mg, 9.40 mmol) in 1 :1 THF/water (20 mL) at 0°C was added a solution of benzyl chloroformate (1.05 mL, 7.12 mmol) in THF (3 mL). The mixture was allowed to warm to room temperature and stirred overnight. The THF was removed in vacuo and the mixture extracted with ethyl acetate (x3). The organic phase was dried over MgSO4, filtered and concentrated under reduced pressure to afford a clear oil. Purification by column chromatography (0 to 5% MeOH in DCM) afforded the desired alcohol intermediate (1.895 g, 86%).

To a solution of oxalyl chloride (0.587 mL, 6.77 mmol) in DCM (15 mL) at -78'C was added DMSO (0.96 mL, 14 mmol). The mixture was stirred at -78°C for 0.5 h, before the addition of the alcohol intermediate (1.675 g, 4.51 mmol) in DCM (8 mL). The reaction mixture was stirred for 1 hour, then TEA (3.14 mL, 22.5 mmol) was added and the reaction mixture was allowed to warm to room temperature, then concentrated in vacuo. Purification by column chromatography (0 to 10% MeOH in DCM) afforded compound 13 as a clear oil (1.352 g, 81 %).

Compound 14

To a solution of compound 12 (1.44 g, 1.94 mmol) and compound 13 (0.858 g, 2.32 mmol) in MeOH (20 mL) was added sodium cyanoborohydride (0.243 g, 3.87 mmol) and the mixture warmed to 35°C for 48 hours. LCMS analysis indicated about 40% conversion to product and some decomposition, therefore the reaction was stopped. The solvents were removed under reduced pressure and the residue was purified by silica gel column chromatography (0 to 5% MeOH in DCM) to afford compound 14 as a clear oil (557 mg, 29%).

15

Compound 15

To a solution of compound 14 (557 mg, 0.566 mmol) in MeCN (3 mL) was added piperidine (0.56 mL, 5.66 mmol) and the mixture stirred at room temperature for 0.5 hours. LCMS analysis indicated the reaction was complete. The solvents were removed under reduced pressure, and the residue triturated with diethyl ether to afford compound 15 as a pale-yellow oil (316 mg, 75%).

17

Compound 17

A mixture of compound 15 (100 mg, 0.1314 mmol), 2-bromomethylphenylboronic acid pinacol ester (117 mg, 0.393 mmol) and potassium carbonate (54 mg, 0.391 mmol) in MeCN (2 mL) was stirred at room temperature for 1 hour.

LCMS analysis indicated the reaction was complete. The reaction mixture was filtered to remove solids and the filtrate was concentrated under reduced pressure to afford crude compound 17 as an oil (220 mg), which was used without further purification.

Compound 18

A mixture of crude compound 17 (156 mg, 0.314 mmol) and potassium hydrogen fluoride (101 mg, 3.14 mmol) in 1 :1 MeCN/water (4 mL) was stirred at room temperature for two hours. LCMS analysis indicated the reaction was complete. The solvents were removed under reduced pressure, and the residue taken up in MeCN, filtered and concentrated to afford compound 18 as a clear oil (176 mg), which was used without further purification.

19

Compound 19

To a solution of compound 18 (150 mg, 0.314 mmol) in MeOH (5 mL) was added Pd/C (10wt%, 50 mg) and the mixture stirred under an atmosphere of hydrogen for 18 hours at room temperature. LCMS analysis indicated that the Cbz-group had been fully cleaved, and the BF3 esters had been partially hydrolysed. The catalyst was removed by filtration and the residue diluted with water (2 mL) and treated with potassium hydrogen fluoride (100 mg). The resulting reaction mixture was stirred at room temperature for 0.5 hours, then the solvents were removed and the residue was taken up in MeCN, filtered to remove solids and the filtrate was concentrated under reduced pressure to afford 19 as a white foam (119 mg).

1

Compound 1

To a solution of compound 19 (100 mg, 0.098 mmol) and triethylamine (0.064 mL, 0.46 mmol) in MeCN (3 mL) at 0'C was added acryloyl chloride (13 uL, 0.16 mmol). The reaction mixture was allowed to warm to room temperature and stirred for 0.5 hours. LCMS analysis indicated the reaction was complete. The solvent was removed under reduced pressure (30°C water bath) to afford compound 1 as an oil (193 mg, contaminated with EtaN HCI salt).

¹H NMR Data for compound 1 is shown in Figure 20, upper panel. LC/MS: m/z 957.5 [M+H]⁺, 487.8 [M+H+NH4]²⁺, 479.0 [M+2H]²⁺

RT 4.04 min (Method 1); m/z 479.0 (M+2H)²⁺ (ESI⁺);

¹ H NMR (CDCI₃ , 400 MHz): 8.05 (br s, 1 H), 7.74 (m, 2H), 7.35 (m, 2H), 7.20 (m, 2H), 7.19 (m, 2H), 7.00 (s, 1 H), 6.17 (dd, J = 16.6 Hz, J = 8.4 Hz, 1 H), 6.11 (dd, J = 16.4 Hz, J = 3.4 Hz, 1 H), 5.51 (dd, J = 8.4 Hz, J = 3.6 Hz, 1 H), 4.80 (br s, 2H), 4.3 (br s, 2H), 3.65 (br s, 2H), 3.70-3.40 (m, 40H), 3.22 (s, 3H), 2.2-1 .6 (m, 12H)

Bis-boronic acid analogue of 1

The compounds bearing a -BF3 group, as for example compound 1, are presumed to convert to corresponding boronic acid compounds in aqueous conditions (see Ma et al., Chem. Commun., 2009, 532-534) . Half of the crude material from above (about 100 mg) was partitioned between DCM and water. The organics were concentrated to afford about 73 mg. This material was taken up in 1 :1 MeCN/water (2 mL) and LIOH (about 10 mg) was added. Stored in the freezer overnight. LCMS analysis indicated the hydrolysis was complete. Solvents removed and the residue taken up in MeCN, filtered and concentrated to afford the bis-boronic acid analogue as a clear oil (80 mg).

bis-boronic acid analogue of 1

¹H NMR Data for compound bis-boronic acid analogue of 1 is shown in Figure 20, lower panel.

Synthesis of BIS2

Compound 3

To a solution of IT1PEG5NH2 (5 g, 19.89 mmol) and triethylamine (5.5 mL, 39.8 mmol) in dry DCM (50 mL) at -78°C was added chloroacetyl chloride (2.4 mL, 29.8 mL) dropwise. The reaction mixture was allowed to warm to room temperature and stirred for a further 0.5 hours. LCMS analysis indicated the reaction was complete. The reaction mixture was filtered through cotton wool and the filtrate was concentrated under reduced pressure to give crude compound 3, which was used without further purification.

Compound 5

A mixture of compound 3 (1.304 g, 3.978 mmol), 1-(N-Boc-aminomethyl)-4-(aminomethyl)benzene (1.41 g, 5.97 mmol), sodium iodide (0.39 g, 0.2 eq.) and triethylamine (1.1 mL, 7.96 mmol) in MeCN (20 mL) was warmed to 30°C for 48 hours. LCMS analysis indicated the reaction was complete. The reaction mixture was filtered through cotton wool, then concentrated under reduced pressure. The residue was partitioned between ethyl acetate and water, and the aqueous phase concentrated under reduced pressure to afford compound 5.

Compound 6

To a mixture of compound 5 (2.099 g, 3.978 mmol) and potassium carbonate (0.55 g, 3.978 mmol) in 2:1 MeCN/H2O) (30 mL) was added Fmoc-OSu (1.342 g, 3.978 mmol) and the resulting mixture was stirred rapidly at 30 °C for 1 hour. The reaction mixture was filtered through cotton wool and the solvents were removed under reduced pressure. The residue was taken up in DCM, filtered and purified by column chromatography twice (gradient: 0 to 5% MeOH) to afford compound 6 as an orange oil (0.765 g, 26% over three steps).

Compound 7

Compound 6 (3.35 g) was dissolved in 3N HCI in MeOH (40 mL) and the resulting reaction mixture was stirred at room temperature for 5 hours. TLC analysis indicated the reaction was complete. The solvents were removed under reduced pressure to afford crude compound 7 as a yellow foam (2.982 g).

Compound 9 A mixture of NH2-PEG5-OH (2.20 g, 9.27 mmol) and BOC2O (3.035 g, 12.64 mmol) in EtOH (20 mL) was stirred at room temperature for 70 hours. LCMS analysis indicated about 40% conversion. Further BOC2O (1 g) and DMAP (cat.) were added, and the mixture was heated at 70°C for 3 hours. LCMS showed almost complete conversion of the starting material and the solvents wereremoved under reduced pressure. The residue was purified by silica gel column chromatography (gradient: 0 to 5% MeOH in DCM) to afford compound 9 as a clear oil (1.720 g).

Compound 10

To a solution of oxalyl chloride (0.66 mL, 7.6 mmol) in DCM (8 mL) at -78°C was added DMSO (1.1 mL, 15 mmol). The mixture was stirred at -78°C for 0.5 h, before the addition of compound 9 (1.720 g, 5.098 mmol) in DCM (6 mL). The reaction mixture was stirred for 1 hour, EtaN (3.6 mL, 26 mmol) was added, then the reaction mixture was allowed to warm to room temperature. The mixture was diluted with water and extracted with DCM, the organic phase was dried over MgSO4 and concentrated under reduced pressure to afford 10 as an oil (1 .733 g).

Compound 14

To a solution of compound 10 (0.342 g, 1.02 mmol) and compound 7 (0.500 g, 0.742 mmol) in MeOH (10 mL) was added sodium cyanoborohydride (0.0.91 g, 1.4 mmol) and the mixture warmed to 30°C for 2 hours. LCMS analysis indicated the reaction was complete. The solvents removed under reduced pressure and the residue was purified by silica gel column chromatography (gradient: 0 to 5% MeOH in DCM) to afford compound 14 as a white foam (497 mg, 70%).

Compound 15

To a solution of compound 14 (497 mg, 0.566 mmol) in MeCN (6 mL) was added piperidine (0.260 mL, 2.64 mmol) and the mixture stirred at room temperature for 3 hours. LCMS analysis indicated the reaction was complete. The solvents were removed under reduced pressure and the residue was purified by silica gel column chromatography (0 to 20% MeOH in DCM) to afford compound 15 as a clear oil (233 mg, 61%).

Compound 22

A mixture of compound 15 (233 mg, 0.31 mmol), 2-bromomethylphenylboronic acid pinacol ester (290 mg, 0.96 mmol) and potassium carbonate (130 mg, 0.94 mmol) in MeCN (5 mL) was stirred at room temperature for 1 hour. LCMS analysis indicated the reaction was complete. The reaction mixture was filtered to remove solids and the filtrate was concentrated under reduced pressure to afford crude compound 22 as an oil (370 mg), which was used without further purification.

Compound 23

A mixture of compound 22 (370 mg, 0.31 mmol) and potassium hydrogen fluoride (240 mg, 3.07 mmol) in 1 :1 MeCN/water (8 mL) was stirred at room temperature for one hour. LCMS analysis indicated the reaction was complete. The solvents were removed under reduced pressure, and the residue taken up in MeCN, filtered and the filtrate washed with hexane and then concentrated to afford compound 23 as a white foam (449 mg, quant), which

Compound 24

HCI (1.25 M) in MeOH (8mL) was added to compound 23 (449 mg) and the reaction mixture was allowed to stir at RT. LCMS analysis indicated complete removal of the Boc protecting group as well as partial hydrolysis of the BF3 groups to the boronic acid). The reaction mixture was concentrated under reduced pressure and the residue was taken up in water (4 mL) and MeCN (4mL) and treated with potassium hydrogen fluoride (240 mg). The resulting reaction mixture was stirred at room temperature for 0.5 hours, then the solvents were removed and the residue was taken up in MeCN, filtered to remove solids and the filtrate was concentrated under reduced pressure to afford compound 24 as a colourless oil (300 mg).

Compound 1

To a solution of compound 24 (300 mg, 0.31 mmol) and triethylamine (0.25 mL, 1.80mmol) in MeCN (10 mL) at O°C was added acryloyl chloride (45 uL, 0.56 mmol). The reaction mixture was allowed to warm to room temperature and stirred for 1.5 hours. LCMS analysis indicated the reaction was complete. The solvent was removed under reduced pressure (30°C water bath) and the residue was dissolved in MeCN and washed with hexane. The solvent was removed under reduced pressure to afford compound 1 an oil (379 mg).

RT 3.95 min (Method 1); m/z 507.2 (M)²⁺ (ESI⁺); ¹H NMR (CDCI₃ , 400 MHz): 8.68 (br s, 1 H), 8.32 (br s, 1 H), 7.72-7.15 (m, 12H), 6.17 (dd, J = 16.6 Hz, J = 8.4 Hz, 1 H), 6.11 (dd, J = 16.4 Hz, J = 3.4 Hz,1 H), 5.61 (dd, J = 8.4 Hz, J = 3.6 Hz, 1 H), 4.94-4.28 (m, 10H), 3.70-3.40 (m, 40H), 3.28 (s, 3H).

Synthesis of FURPEGS 2-[2-[2-[2-(2-Acryloylamidoethoxy)-ethoxy]ethoxy]ethoxy]ethoxy]ethyl-alpha-D-

Compound 2

MsCI (302 pL, 3.90 mmol) in anhydrous DCM (3 mL) was added slowly over 30 min to a stirred and cooled mixture (0°C) of EtaN (726 pL, 5.21 mmol) and compound 1 (800 mg, 2.603 mmol) in anhydrous DCM (3 mL). The reaction mixture was stirred at 0 °C for 90 min and then at room temperature for 2 hours. The reaction mixture was then concentrated under reduced pressure, diluted with DCM and washed with 1 M HCI and Brine. The organic layers were dried over MgSO4 and concentrated to obtain crude compound 2 as a yellow oil (1 g, 2.595 mmol, quantitative) whih was used in the next step without further purification.

Compound 4

2,3:5,6-Di-o-isopropylidene-alpha-d-mannofuranose 3 (439 mg, 1.69 mmol) was dissolved in toluene (6 mL) and NaOH (50% in water, 6mL) was added. After stirring for 15 min at room temperature tetrabutylammonium bromide (502 mg, 1.58 mmol) was added followed by a solution of compound 2 (500 mg, 1.297 mmol) in toluene (3 mL). After 24h LCMS showed the reaction was complete and it was neutralised with 5M HCI (0°C) until pH 7 and the product was extracted with EtOAC. The organic layer was washed with water and brine, dried over MgSO4, filtered and concentrated under reduced pressure. The crude product was purified by silica gel column chromatography (EtOAc in PE: 30% to 100%) to afford pure compound 4 (436.5 mg, 0.79 mmol, 61 %) as a colourless oil.

Compound 5

Compound 4 (100 mg, 0.18 mmol) was dissolved in MeCN/H2O=1/1 (2 mL) and silica sulphuric acid 3% (~10 mg) was added. The reaction mixture was rotated on a rotary evaporator at 40 °C. After 24h LCMS showed all starting material was converted to the mono-protected intermediate, and more silica sulphuric acid was added (~10 mg) and rotation continued over night at 40 °C. Further LCMS analysis showed slow conversion into the fully deprotected compound 4. The entire process of deprotection of both acetonides took ~ 1 week (rotation in the buchi at 40 °C). After LCMS confirmed the formation of the desired product, the silica sulphuric acid was removed by filtration. A pH indicator showed that the solution was acidic and a few drops of EtaN were added to adjust to pH 9- 10. The crude product solution was directly applied to a C18 column and the product was eluted with a 5-95% gradient of MeCN in H2O to afford compound 5 (50.5 mg, 0.108 mmol, 59%) as a colourless oil.

Compound 6

Compound 5 (50 mg, 0.107 mmol) was dissolved in pyridine (2mL) and acetic anhydride (0.7 mL, 7 mmol) was added. After stirring the reaction mixture for 5 hours at room temperature LCMS confirmed the reaction was complete and the reaction mixture was concentrated and co-evaporated with toluene x3. The crude product was combined with a second batch of crude product and dissolved in DCM, washed with 1 M HCI (x3), NaHCO3, Brine and dried over MgSO4. Purification by silica gel column chromatography (gradient: 3 to 20% MeOH in DCM) gave 214 mg of compound 6 as a clear oil. Compound 7

Compound 6 (200 mg, 0.314 mmol) was dissolved in MeOH (3 mL) and Pd/C (catalytic amount) was added. The suspension was stirred under H2 overnight. The catalyst was removed by filtration over celite and the filtrate was concentrated under reduced pressure. LCMS analysis showed that partial cleavage of the acetyl protecting groups had accompanied the reduction of the azide group, therefore compound 7 (138mg) was used without further purification in the next step.

Compound 8

Compound 7 (138 mg, 0.311 mmol) was dissolved in DMF (3 mL, 38.8 mmol), the solution was cooled at 0°C and EtaN (87 pL, 0.624 mmol) followed by acryloyl chloride (28 pL, 0.3440 mmol) was added. The reaction mixture was stirred at r.t. After 2h LCMS analysis showed no SM left and the reaction mixture was concentrated under reduced pressure to give crude compound 8 (200 mg, 0.4020 mmol), which was used without further purification in the last step.

Compound 9

To a solution of compound 8 (200 mg, 0.344 mmol) in anhydrous MeOH (3 mL) was added NaOMe (30% in MeOH 2 pL, 0.011 mmol). The reaction mixture was stirred at room temperature for 4 hours. Amberlite cation-exchange resin (IRC120, H+ form) was added to adjust the pH to 7 and the resin was removed by filtration. The filtrate was concentrated under reduced pressure and the crude product was purified over a C18 flash column eluting with 2% to 20% MeCN in H2O followed by a second C18 column, eluting 0 to 2% MeOH in H20 to give compound 9 (88 mg) as colourless sticky oil.

¹H NMR, ¹³C NMR, ¹H-¹H COSY and ¹H-¹H HSQC spectra for the final product are shown in Figure 21.

RT 5.06 min (Method 3); m/z 498.4 (M+H)⁺ (ESI⁺);

¹H NMR (D₂0, 400 MHz): 6.28 (dd, J = 10.3 Hz, J = 7.7 Hz, 1 H), 6.19 (d, J = 7.7 Hz, 1 H), 5.76 (d, J = 10.3 Hz, 1 H), 5.05 (s, 1 H), 4.32 (m, 1 H), 4.17 (m, 1 H), 4.07 (d, J = 8.7 Hz, 1 H), 3.97-3.56 (m, 25H), 3.47 (m, 1 H), 3.19 (m, 1 H)

Synthesis of BIS3

Compound 2

A mixture of NH2-PEG5-OH (2.10 g, 8.8 mmol), BOC2O (3.9 mmol, 17.6 mmol) and EtaN (2.5 ml, 17.6 mmol) in DCM (20 mL) was stirred at room temperature for 16 hours. The reaction mixture was diluted with DCM, washed with water, dried over MgSO4 and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (gradient: 0 to 40% MeOH in DCM) to afford compound 2 as a clear oil (2.13 g, 71 %).

Compound 3

To a solution of oxalyl chloride (0.081 mL, 0.93mmol) in DCM (8 mL) at -78°C was added DMSO (0.095 mL, 1.33 mmol). The mixture was stirred at -78°C for 0.5 h, before the addition of compound 2 (0.23 g, 0.67 mmol) in DCM (6 mL). The reaction mixture was stirred for 0.5 hour, EtaN (0.35 mL, 2 mmol) was added, then the reaction mixture was allowed to warm to room temperature. The mixture was diluted with water and extracted with DCM, the organic phase was dried over MgSO4 and concentrated under reduced pressure to afford crude compound 3 (quant) as an oil.

Compound 6

To a mixture of tert-butyl N-(6-aminohexyl)carbamate (1 g, 4.62 mmol) and pyrene-1-carbaldehyde (0.920g, 3.99 mmol ) in anhydrous DCM (30mL) sodium triacetoxyborohydride (1.4g, 6.6 mmol) was added and the reaction mixture was stirred at room temperature for 6h. LCMS the reaction had gone to completion. The reaction mixture was diluted with DCM, washed with water, dried over MgSO4 and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (gradient: 0 to 15% MeOH in DCM) to afford compound Boc protected precursor of 6 (0.998 g, 58%).

The Boc-protected intermediate was dissolved in DCM (8mL) and 5M hydrochloric acid in 2-propanol (2.3 mL) was added. The reaction mixture was allowed to stir at room temperature for 16h. LCMS showed complete removal of the Boc protecting group and the solvents were removed under reduced pressure. The residue was taken up in MeOH and Amberlite 900 (in OH- form) was added to desalt the product. After stirring for 15 minutes the resin was removed by filtration and the filtrate was concentrated under reduced pressure to afford compound 6 (0.93g, 57%) in the free base form.

Compound 7

Sodium triacetoxyborohydride (1.1g, 4.71 mmol) was added to a solution of compound 3 (0.600g, 1.8mmol) and compound 6 (0.93g, 2.3mmol) in anhydrous THF (14mL) and the resulting reaction mixture was stirred at room temperature for 18h. The reaction mixture was diluted with DCM and washed with water. The aqueous phase was extracted with DCM and the combined organic layers were dried over MgSO4 and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (gradient 0 to 20% MeOH in DCM) to give compound 7 (750mg, 65% yield). Compound 8

2-[2-(Bromomethyl)phenyl]-4,4,5,5-tetramethyl-1 ,3,2-dioxaborolane (91 mg, 0.32 mmol) was added to a stirring solution of compound 7 (99mg, 0.15mmol) and potassium carbonate (110mg, 0.75 mmol) in anhydrous acetonitrile (12 mL) at room temperature. After 1 h, LCMS indicated product formation was complete and the reaction mixture was centrifuged to remove the solid potassium carbonate and the collected supernatant was then filtered over a 200 micron syringe filter and concentrated under reduced pressure to give bis boronic ester intermediate (135mg). The latter was dissolved in DCM (5mL), the resulting mixture was cooled to 0°C and 4.5 ml of HCI (6M in I PA) was added. After stirring for 5 hours at room temperature the reaction mixture was concentrated under reduced pressure. The residue was purified by silica gel column chromatography (DCM:MeOH: aq ammonia; 23:3:0.5) to afford the bis boronic acid intermediate (100mg). The bis-boronic acid intermediate was dissolved in MeOH (1 mL), potassium hydrogen fluoride (73 mg, 6 eq) was added and the resulting mixture was stirred at 37°C for 1 hour. As LCMS analysis showed only 30% product formation 4mL of water was added. LCMS analysis after a further 30 minutes showed complete conversion to product and the reaction mixture was concentrated under reduced pressure. The residue was co-evaporated with acetonitrile, then taken up in MeCN, filtered and the filtrate was concentrated to afford compound 8 (102 mg).

Compound 9

To a solution of compound 8 (102 mg) in anhydrous DCM (8mL) at 0 °C was added potassium carbonate (5 equiv., 0.579 mmol) and acryloyl chloride (1.2 equiv, 0.139 mmol). The resulting reaction mixture was stirred at room temperature for 20 minutes and then filtered over a syringe filter and concentrated under reduced pressure. The residue was dissolved in MeCN (5mL) and the resulting solution was added dropwise to diethyl ether (40mL). The formed solids were collected by centrifugation to give compound 9 (94 mg, 88%).

¹H NMR spectrum of the final compound is shown in Figure 22.

RT 5.06 min (Method 1); m/z 942.7 (M+Na+H)⁺ (ESI⁺);

¹H NMR (CD₃CN, 400 MHz): 8.52 (s, 1 H), 8.30-7.96 (m, 9H), 7.62-7.45 (m, 3H), 7.29-6.87 (m, 5H), 6.17 (dd, J = 16.6 Hz, J = 8.4 Hz, 1 H), 6.11 (dd, J = 16.4 Hz, J = 3.4 Hz, 1 H), 5.54 (dd, J = 8.4 Hz, J = 3.6 Hz, 1 H), 4.25 (br s, 2H), 4.10 (br s, 2H), 3.91 (br s, 2H), 3.64-3.22 (m, 18H), 2.93 (br s, 2H), 2.66 (br s, 2H), 2.51 (br s, 2H), 1.50 (br s, 2H), 1.33 (br s, 2H), 1.11 (br s, 2H), 0.90 (m, 2H)

Fabrication of the hydrogel sensor

In a typical formulation of the hydrogel sensor the monomers and molar % are as follows: Boronic acid acrylamide 8 mol%, inhibitor acrylamide 8 mol%, acrylamide 82 mol%, and methylene bis acrylamide 1-2 mol%.

Monomers are diluted either in deionized (DI) water, 1 M fructose or mannitol solution in PBS (pH 7.4, 0.132 M NaCI), to give a final total monomer concentration of 1.0 or 1.5 M. 1 -Hydroxycyclohexyl phenyl ketone (photoinitiator) is added at a concentration of 1 .5 mM.

Table 1. Example of components of the pregel in a glucose-binding molecule (GBM)-inhibitor (INH) scanning experiment.

Targeted mol % in the pregel

Fabrication of the hydrogel sensor follows that described in WO 2007/104974 (which is incorporated herein by reference in its entirety). Firstly, optical glass fibers are stripped and cleaved to prepare a uniform cleave. Fiber cleaves are then silanized to provide covalent attachment of the hydrogel to the glass surface. Silanization involves firstly submerging fiber cleaves in hydrochloric acid (1.0 M) for 15 minutes, followed by washing with DI water and then submerging in ethanol containing 3-(trimethoxysilyl)propyl methacrylate (84 mM) for 10 minutes. Excess 3- (trimethoxysilyl)propyl methacrylate is removed by washing fiber cleaves under flowing ethanol. A droplet of the pregel solution resembling a dome is deposited onto the fiber cleave using a pipette while both cleave and pregel are inside a larger droplet of squalane oil. The oil firstly serves to maintain the stability of the pregel droplet and secondly contains an excess of dissolved photoinitiator 1 -hydroxycyclohexyl phenyl ketone (132 mM). The excess photoinitiator in the oil is necessary to enable the polymerization to occur without oxygen-free conditions whereby radicals generated firstly react with dissolved oxygen in the oil. The higher concentration in the oil compared to the pregel droplet also ensures that photoinitiator does not significantly leach out of the pregel droplet into the oil droplet.

Polymerisation of the pregel occurs via irradiation (5 minutes) of the pregel by a 340 nm UV LED light source positioned directly in front of the pregel droplet and inside the droplet of oil.

After polymerization, sensors are washed briefly in pentane to remove the oil and then further washed in 50% ethanol in DI water for 15 minutes to remove unreacted monomers. At this point sensors are placed in PBS pH 6.0 until testing.

Sensors containing 8 mol% BIS3:

were unable to be cured with UV light at various wavelengths owing to strong absorbance of the UV by the pyrene and pyrene excimer. BIS3 was therefore covalently bound to the hydrogel via thiol-ene post-modification as demonstrated by work from the Du Prez group (Espeel, P., Goethals, F., Stamenovic, M. M., Petton, L. & Du Prez, F. E. Double modular modification of thiolactone-containing polymers: Towards polythiols and derived structures. Polym. Chem. 3, 1007-1015 (2012)): A monomer solution containing 8 mol% thiolactone and 8 mol% inhibitor was polymerized as usual with 340 nm light. The polymerized sensors were then incubated in a solution of 1:1 DMSO and PBS with 25 mM of the alkene (BIS3) and after a short period of time ethanolamine was added (final concentration 5 M) to start the reaction. The reaction was left overnight at room temperature with stirring and after this time the sensors were washed with 50% ethanol in DI water for 15 minutes before testing.

Sensor experiment setup

In a typical experiment, test solutions are prepared using 0.01 M PBS containing 132 mM NaCI at pH 7.4 at 37 degrees Celsius. Sensors are submersed in test solutions and allowed to equilibrate for at least 10 minutes, after which time, the gel cavity signal is locked to give an initial absolute length of the hydrogel and the experiment is started. At timepoints, portions of glucose in PBS from a 1 M stock solution which has been left for at least 6 hours to reach mutarotation equilibrium, are added to achieve the desired concentrations while the change in gel length is continuously monitored. Length changes in response to pH are measured by moving sensors between two test solutions at a constant glucose concentration but a different pH.

Dye displacement assay

The dye displacement assay was reproduced as described in the literature (Springsteen, G. & Wang, B. A detailed examination of boronic acid-diol complexation. Tetrahedron 58, 5291-5300 (2002); Brooks, W. L. A., Deng, C. C. & Sumerlin, B. S. Structure-Reactivity Relationships in Boronic Acid-Diol Complexation. ACS Omega 3, 17863— 17870 (2018)). Briefly, this three-way competitive binding assay involves the formation of a fluorescent complex between Alizarin Red S (ARS) and boronic acid (BOB) which can be competitively displaced by the addition of a diol, resulting in a boronic acid-diol complex and non-fluorescent ARS. Firstly, the association constant between ARS and BOB (KARS) must be determined which is achieved by titrating BOB against a constant ARS concentration and measuring the fluorescence intensity. The calculations used to derive the relationship between KA S and the fluorescence intensity are described in the work by Brooks et al. Secondly, to calculate the association constant between the boronic acid and the diol (K_eq), the diol was titrated against a constant concentration of ARS and BOB (Brooks, 2018).

To measure the equilibrium constant between the boronic acid BOB and ARS (KARS) two solutions were prepared in 0.1 M phosphate buffer (pH 7.4) with 10% DMSO; one containing the boronic acid (BOB) (2.0 x 10³ M) and ARS (9.0 x 10⁶ M) (S1), and the other containing only ARS (9.0 x 10⁶ M) (S2). A titration was performed of constant ARS concentration against a decreasing BOB concentration (Table 2).

Table 2. Example of titration experiment performed to calculate K(ARS), carried out in 0.1 M phosphate buffer pH 7.4 at room temperature.

Solutions were mixed in a black, clear-bottomed 96 well plate and allowed to react for 5 minutes at room temperature, at which point fluorescence emission intensity was measured for each entry (ex = 468 nm; em = 572 nm), in triplicates.

KARS was calculated by plotting a graph of 1 /fluorescence intensity (I) vs 1/[BOB] and dividing the intercept by the gradient.

To measure the equilibrium constant between the boronic acid (BOB) and diol (K_eq), three solutions were prepared in 0.1 M phosphate buffer (pH 7.4) with 10% DMSO; one containing the boronic acid (BOB) (2.0 x 10³ M) and ARS (9.0 x 10⁶ M) (S1), one containing only ARS (9.0 x 10⁶ M) (S2) and one containing (BOB) (2.0 x 10³ M), ARS (9.0 x 10⁶ M) and the diol in question (1.0 or 0.1 M) (S3). A titration was performed at a constant BOB and ARS concentration against a decreasing diol concentration (Table 3).

Table 3. Example of titration experiment performed to calculate K(eq) carried out in 0.1 M phosphate buffer pH 7.4

Solutions were mixed in a clear-bottomed, black 96 well plate and allowed to react for 5 minutes, at which point fluorescence emission intensity was measured for each entry (ex = 468 nm; em = 572 nm), in triplicates. K_eq was calculated by plotting a graph of [diol] / P vs Q, where P = [BA] -(1/Q*KARS)-([ARS]/1 +Q) and Q = (IBA-ARS -

I)/(I-IARS) and dividing KA S by the gradient.

Average sensitivity of different sensor configurations is shown in Table 4 hereinbelow. Table 4. Average sensitivity of different sensor configurations.

Average sensitivity (O-2O mM glucose) dL/L (%) GBM:INH 1:1

GBM no inhibitor SOR_PEG5 FUR_PEG5 GLU_PEG5 MAN_PEG5 GEMA GLY TRIS

BOB 5.2 2.2 3.8 5.1 6.4 5.5 6.3 8.8

BIS1 3.7 0.16 10.9 - 2 2.2 - 6.1

BIS2 0.7 - - - - - - O.9

BIS3 1.9 O.5 - - - - - 1.4 Results and discussion

A library of different boronic acid-based GBMs were tested against a library of potential inhibitor molecules to identify the feasibility of using a GBM and inhibitor to enhance the sensitivity of the sensor towards glucose (see Table 4), as well as to increase the linearity and decrease the response time. The inhibitors tested possess different diol moieties which were expected to have different binding affinities to boronic acids, for example SORPEGS and FURPEGS were expected to be stronger than MANPEGS which was expected to be stronger than GLUPEGS.

BOB is a class of internally coordinated boronic acids with a pKa of around 7.2 making it an attractive GBM for use in a physiological setting ("Benzoboroxoles as Efficient Glycopyranoside-Binding Agents in Physiological Conditions: Structure and Selectivity of Complex Formation” J. Org. Chem., 2008, 73, 6471-6479 DOI: 10.1021/jo800788s). Hydrogel sensors produced with BOB swelled with increasing glucose rather than shrank. BOB is reported to bind to the pyranose form of glucose in a 1 :1 complex which may explain the swelling rather than shrinking behavior ("An Improved Class of Sugar-Binding Boronic Acids, Soluble and Capable of Complexing Glycosides in Neutral Water” J. AM. CHEM. SOC. 2006, 128, 4226-4227 DOI: 10.1021 /ja057798c). Copolymerizing BOB with 1 eq. inhibitors resulted in an enhancement in sensitivity of the sensor for some inhibitors (TRIS, MANPEGS) and a reduction in sensitivity for others (SORPEGS, FURPEGS) when compared to the hydrogels containing only the glucose binding BOB. Inhibitors which did not significantly change the response (GEMA, GLY) were not further tested. Overall sensitivity for BOB sensors was promising at physiological pH, and thus a more thorough investigation on the copolymerization of different inhibitors with BOB was carried out to determine if the sensor properties could be enhanced with an optimized ratio. In this regard, 5 different inhibitors were tested (GLU, MANPEGS, TRIS, FURPEGS, SORPEGS), all possessing the same PEG linker and acrylamide unit. Pre-gels were formulated to target increasing eq. of the inhibitor with respect to BOB (Table 1), and the sensitivity and pH response of the resulting hydrogel sensor was then tested.

The sensitivity was determined as the change in length (AL/L) of the hydrogel from 0 mM glucose to 20 mM glucose in PBS pH 7.4 at 37 °C. For inhibitors TRIS and FURPEGS, the sensitivity of the sensor increased to a maximum on addition of 1.0 and 0.5 equivalent respectively, at higher equivalents, the sensitivity dropped. In the case of TRIS, the sensors with higher equivalents of inhibitor (1.5-3.0) still showed a much higher sensitivity than those without inhibitor. In the case of FURPEGS, the sensitivity dropped more steeply than that seen with TRIS, displaying a slightly lower sensitivity than BOB without the inhibitor at 1.0 equivalents and almost complete inhibition of the glucose response after 2.0 eq. of the inhibitor was added (Figure 9). GLUPEGS did not appear to significantly change the sensitivity of the sensor at the equivalents tested, indicating that there was no, or very low interaction between GLUPEGS and BOB. This is unsurprising since the pyranose form of GLUPEGS does not possess a cis-diol, usually needed to form a strong bond with boronic acids ("Selective sensing of saccharides using simple boronic acids and their aggregates" Chem. Soc. Rev., 2013, 42, 8032 DOI: 10.1039/c3cs60148j). In the case of SORPEGS, 0.5 eq. already resulted in a reduction of the sensitivity over the BOB-only sensor and higher equivalents resulted in complete inhibition of the glucose response. The result for SORPEGS indicated a strong bond between the SORPEGS and BOB, which could not easily be displaced by glucose. Finally, in the case of MANPEGS, the sensitivity of the sensor increased with increasing equivalents, without a maximum being observed (Figure 9).

Taken together, these results indicate that different inhibitors require a certain molar ratio to achieve a maximum swelling effect with glucose (sensitivity) and this is likely due to differences in the binding strength of the inhibitor and the GBM. Statistical binding effects applicable to multivalent systems such as the hydrogel sensor here, can help explain the increased sensitivity at lower molar ratio despite inhibition of the glucose response seen at higher ratios, for example with FURPEGS ("Influencing Receptor-Ligand Binding Mechanisms with Multivalent Ligand Architecture" J. AM. CHEM. SOC. 2002, 124, 14922-14933 DOI: 10.1021/ja027184x).

Next, the impact of inhibitors on the pH response of sensors was tested. For this, sensors were exposed to PBS at 37 degrees C supplemented with 2.2 mM glucose at pH 7.4, pH 6.9 and pH 7.6 to simulate the extreme pH range that could be experienced in the intensive care unit (ICU). The change in length of the hydrogel sensor (AL/L) as a result of changing pH was measured. An ideal sensor would display no change in length on moving from pH 6.9 to 7.4 and from 7.4 to 7.6.

Sensors with only the glucose binding moiety BOB, and without inhibitor (BOB-only) sensors had disappointing interference at pH 6.9, displaying a sharp shrinking of the hydrogel sensor on moving from pH 7.4 to pH 6.9 (Figure 10 (upper)). A smaller but significant interference was observed moving from pH 7.4 to pH 7.6 (Figure 10 (lower)). However, when BOB was copolymerized with inhibitors (MANPEGS, TRIS, FURPEGS, SORPEGS), the response to pH change was reversed, with lower pH resulting in a swelling and higher pH resulting in a shrinking. The ratio at which the reverse response was observed depended on the apparent strength of the inhibitor. This behavior was unexpected but may be explained by breaking of BOB-inhibitor bonds at lower pH, leading to a swelling, and forming of BOB-inhibitor bonds at higher pH, leading to a shrinking. As with the sensitivity results, the GLUPEGS inhibitor did not induce a change in pH response - indicating that there is no BOB-GLUPEGS interaction. Importantly in the case of the MANPEGS inhibitor, at 1.5-3.0 equivalents, pH interference at both pH 6.9 and pH 7.6 was significantly reduced, and at 1.5 equivalents, almost completely removed. Thus, combining BOB with 1.5-2.0 equivalents of MANPEGS resulted in a superior glucose sensor with very low pH interference and a higher glucose sensitivity over using a sensor with BOB alone.

The extremely high sensitivity increase observed for TRIS sensors (Figure 9) was postulated to be due to the shorter linker length in comparison to the other inhibitors tested. To test this, two more mannoside inhibitors were synthesized with decreasing linker lengths, MANPEG2 and MAN, and tested in combination with BOB in the same way as described previously. A small enhancement in the sensitivity was observed for MANPEG2 at 1.5 equivalent and a significant enhancement in the sensitivity was observed for MAN displaying a sensitivity maximum around 2 equivalents (Figure 12). Interestingly, the response to pH followed an almost identical trend to that of the MANPEGS inhibitor, indicating that this property is related to the binding strength of the inhibitor, whereas the magnitude of the swelling is related to the linker length, being the highest for shorter linkers (Figure 13, 14).

Taken together, an optimized glucose sensor consisting of BOB and 1.5 eq. of MANPEG2 resulted in a significant sensitivity enhancement and negligible response to changing pH, substantially improving the sensor's usefulness over that of the BOB-only condition (without inhibitor) (Figure 12, Figure 8).

To confirm whether the trend in sensitivity observed was due to differences in the affinity of the diol to BOB, a dye displacement assay was carried out to calculate the binding constant (K_eq) between BOB and mimics of the inhibitors (Figure 15, Figure 16) (Springsteen, G. & Wang, B. A detailed examination of boronic acid-diol complexation. Tetrahedron 58, 5291-5300 (2002); Brooks, W. L. A, Deng, C. C. & Sumerlin, B. S. Structure- Reactivity Relationships in Boronic Acid-Diol Complexation. ACS Omega 3, 17863-17870 (2018)). The results confirmed the expected trend in inhibitor strength: GLUPEGS < MANPEGS < TRIS < FURPEGS < SORPEGS. The most promising inhibitors with respect to increased sensitivity and ability to easily tune the pH response, possessed affinities to BOB similar to, or slightly below that of D-glucose. MANPEGS displayed a fold change of 0.5 vs D-glucose and TRIS, 1.1 vs D-glucose. FURPEGS, which inhibited glucose response at ratios higher than 1.0 displayed a significantly higher affinity for BOB than D-glucose with a fold change of 18.4, and SORPEGS which completely inhibited glucose response at ratios higher than 0.5, at 23.6 that of D-glucose (Figure 15).

Sensors containing BIS1 (without inhibitors) displayed a very good sensitivity to glucose but suffered from quick saturation with increasing glucose concentration (low linearity) and a slow response time when moving from a higher glucose concentration to a lower concentration (Figures 5 and 6). These observations suggest that BIS1 has a higher affinity for glucose than the monoboronic acids tested. BIS1 sensors copolymerized with inhibitors followed a similar sensitivity trend as for BOB (Figure 4). Importantly the linearity and response time could both be significantly improved by addition of 2 eq. of TRIS as well as increasing the sensitivity to glucose (Figure 7). pH interference of BIS1 sensors was largely unaffected by the addition of inhibitors, probably owing to the lower pKa of the Wulff-type boronic acid not inducing a significant change in inhibitor binding within the pH range tested.

Different polymer backbones

The data demonstrates that various backbones other than simple acrylamide can be used to construct the BOB hydrogel sensor. In the reaction mixture, 8% BOB and 8% MANPEGS (1 : 1 ratio) were used. Acrylamide was replaced with HEAA or HMAA to make up 82.5 mol % of the pregel with 1 .5 mol% comprising Bis acrylamide.

Acrylamide HMAA HEAA HMAA (N-(Hydroxymethyl)acrylamide) was purchased from Sigma Aldrich and used without further purification.

HEAA (N-(Hydroxyethyl) acrylamide) was purchased from Sigma Aldrich and used without further purification.

Different hydrophilic monomers were used in place of acrylamide, in all cases hydrogels with good optical qualities were made and measured. Similar glucose response was observed for HEAA and acrylamide sensors, while HMAA sensors displayed an increased response to glucose relative to acrylamide (Figure 23).

Claims

1 . A biosensor for measuring the concentration of glucose, the biosensor comprising a polymer comprising:

2. The biosensor of claim 1, wherein the boronic acid-based glucose-binding moiety comprises a moiety of formula (la-1) and/or a moiety of formula (lb-1):

wherein each R^s is independently selected from C1-5 alkyl, C2-5 alkenyl, C2-5 alky ny I, -(C0-3 al ky I ene)-0 H , -(C0-3 alkylene)-O(Ci-5 alkyl), -(C0-3 alkylene)-O(Ci-5 alkylene)-OH, -(C0-3 alkylene)-O(Ci-5 alkylene)-O(Ci-5 alkyl), -(C0-3 alkylene)-SH, -(C0-3 alkylene)-S(Ci-5 alkyl), -(C0-3 alkylene)-S(Ci-5 alkylene)-SH, -(C0-3 alkylene)-S(Ci-5 alkylene)-S(Ci-5 alkyl), -(C0-3 alkylene)-NH2, -(C0-3 alkylene)-NH(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-OH, -(C0-3 alkylene)-N(Ci-5 alkyl)-OH, -(C0-3 alkylene)-NH-O(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-O(Ci-5 alkyl), -(C0-3 alkylene)-halogen, -(C0-3 alkylene)-(Ci-5 haloalkyl), -(C0-3 alkylene)-O-(Ci-5 haloalkyl), -(C0-3 alkylene)-CN, -(C0-3 alkylene)-NO2, -(C0-3 alkylene)-CHO, -(C0-3 alkylene)-C0-(Ci-5 alkyl), -(C0-3 alkylene)-COOH, -(C0-3 alkylene)-C0-0-(Ci-5 alkyl), -(C0-3 alkylene)-0-C0-(Ci-5 alkyl), -(C0-3 alkylene)-C0-NH2, -(C0-3 alkylene)-C0-NH(Ci-5 alkyl), -(C0-3 alkylene)-C0-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-C0-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-C0-(Ci-5 alkyl), -(C0-3 alkylene)-NH-C0-0-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-C0-0-(Ci-5 alkyl), -(C0-3 alkylene)-0-C0-NH-(Ci-5 alkyl), -(C0-3 alkylene)-0-C0-N(Ci-5 alkyl)-(Ci-5 alkyl), -(C0-3 alkylene)-SO2-NH2, -(C0-3 alkylene)-SO2-NH(Ci-5 alkyl), -(C0-3 alkylene)-SO2-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-SO2-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-SO2-(Ci-5 alkyl), -(C0-3 alkylene)-SO2-(Ci-5 alkyl), -(C0-3 alkylene)-S0-(Ci-5 alkyl), -(C0-5 alkylene)-carbocyclyl, and -(C0-5 alkylene)-heterocyclyl, wherein one or more -CH2- units in the alkylene moiety in said -(C0-5 alkylene)-carbocyclyl and/or in the alkylene moiety in said -(C0-5 alky lene)-heterocycly I are each optionally replaced by a group independently selected from -O-, -CO-, -CO-O-, -O-CO-, -NH-, -N(CI.₅ alkyl)-, -NH-CO-, -N(CI.₅ alkyl)-CO-, -CO-NH-, -CO-N(CI.₅ alkyl)-, -S-, -SO-, -SO₂-, -SO2-NH-, -SO₂-N(CI.₅ alkyl)-, -NH-SO2-, and -N(CI.₅ alkyl)-SO₂-, and further wherein the carbocyclyl moiety in said -(C0-5 alkylene)-carbocyclyl and the heterocyclyl moiety in said -(C0-5 alky lene)-heterocycly I are each optionally substituted with one or more groups independently selected from C1-5 alkyl, C2-5 alkenyl, C2-5 alkynyl, -OH, -O(Ci-5 alkyl), -O(Ci-5 alkylene)-OH, -O(Ci-5 alkylene)-O(Ci-5 alkyl), -SH, -S(Ci.₅ alkyl), -S(Ci.₅ alkylene)-SH, -S(Ci.₅ alkylene)-S(Ci.₅ alkyl), -NH₂, -NH(CI.₅ alkyl), -N(CI.₅ alkyl)(Ci-₅ alkyl), -NH-OH, -N(CI.₅ alkyl)-OH, -NH-O(CI.₅ alkyl), -N(CI.₅ alkyl)-O(Ci.₅ alkyl), halogen, C1.5 haloalkyl, -O-(Ci.₅ haloalkyl), -CF₃, -ON, -NO₂, -OHO, -CO-(Ci.₅ alkyl), -COOH, -CO-O-(Ci.₅ alkyl), -O-CO-(Ci-5 alkyl), -CO-NH₂, -CO-NH(CI.₅ alkyl), -CO-N(CI.₅ alkyl)(Ci.₅ alkyl), -NH-CO-(CI.₅ alkyl), -N(CI-₅ alkyl)-CO-(Ci.₅ alkyl), -NH-CO-O-(CI.₅ alkyl), -N(CI.₅ alkyl)-CO-O-(Ci.₅ alkyl), -O-CO-NH-(CI.₅ alkyl), -O-CO-N(CI-5 alkyl)-(Ci.₅ alkyl), -SO2-NH2, -SO₂-NH(CI.₅ alkyl), -SO₂-N(CI.₅ alkyl)(Ci.₅ alkyl), -NH-SO2-(CI-5 alkyl), -N(CI-5 alkyl)-SO2-(Ci-5 alkyl), -SO2-(Ci-5 alkyl), -SO-(Ci-5 alkyl), cycloalkyl, and heterocycloalkyl; and wherein n is independently 0, 1 , 2 or 3; and wherein the inhibitor moiety comprises a moiety of formula (Ila), a moiety of formula (lib) and/or a moiety of formula (lie):

(Ila) (lib) (lie)

3. The biosensor of claim 1 or 2, wherein the boronic acid-based glucose-binding moiety comprises a moiety of formula (la-2) and/or a moiety of formula (lb-2):

wherein R^s and n are as defined in claim 2.

4. The biosensor of claim 3, wherein n is 0.

5. The biosensor of claim 3 or 4, wherein the inhibitor moiety comprises a moiety of formula (Ila)

6. The biosensor of claim 5, wherein the boronic acid-based glucose-binding moiety and the inhibitor moiety are present in a molar ratio of from about 1 :1 to about 1 :3.

7. The biosensor of claim 6, wherein the boronic acid-based glucose-binding moiety and the inhibitor moiety are present in a molar ratio of from about 1 :1 to about 1 :2.

8. The biosensor of any one of claims 1 to 7, wherein in the presence of glucose, the boronic acid-based glucose-binding moiety binds to glucose, whereby the bond between the boronic acid-based glucose-binding moiety and the inhibitor moiety is broken, which results in a swelling of the polymer.

9. The biosensor of claim 8, wherein the extent of swelling is substantially linearly proportional to the concentration of glucose.

10. The biosensor of any one of claims 1 to 9, wherein the extent of the change of volume of the polymer in the presence of glucose is substantially independent of the pH value in the range from about pH 7.4 to about pH 7.6.

11. The biosensor of claim 1, wherein the boronic acid-based glucose-binding moiety comprises a moiety of formula (la-2) and/or a moiety of formula (lb-2):

and wherein the inhibitor moiety comprises a moiety of formula (Ila):

wherein the boronic acid-based glucose-binding moiety and the inhibitor moiety are present in a molar ratio of from about 1 : 1 .5 to about 1 : 2.5, preferably about 1 :2.

12. The biosensor of claim 11, wherein the polymer is obtainable in a polymerization reaction of a composition comprising:

wherein q is an integer from 0 to 10, preferably wherein q is an integer from 0 to 5, more preferably wherein q is an integer from 0 to 2, even more preferably wherein q is 0.

13. The biosensor of claim 1, wherein the boronic acid-based glucose-binding moiety comprises a moiety of formula (Ic):

wherein:

R^L is selected from C4-8 alkylene, C4-8 alkenylene, C4-8 alkynylene, -(C0-2 alkylene)-arylene-(Co-2 alkylene)- and -(C0-2 alkylene)-heteroarylene-(Co-2 alkylene)-, wherein the arylene moiety in said -(C0-2 alkylene)- arylene-(Co-2 alkylene)- and the heteroarylene moiety in said -(C0-2 alkylene)-heteroarylene-(Co-2 alkylene)- are each optionally substituted with one or more R^s, and wherein one or more -CH2- units in said C4-8 alkylene, said C4-8 alkenylene or said C4-8 alkynylene are each optionally replaced by a group independently selected from -O-, -S-, -NH- and -N(CI-5 alkyl)-; each R^s is independently selected from C1-5 alkyl, C2-5 alkenyl, C2-5 alkynyl, -(C0-3 alkylene)-OH, -(C0-3 alkylene)-O(Ci-5 alkyl), -(C0-3 alkylene)-O(Ci-5 alkylene)-OH, -(C0-3 alkylene)-O(Ci-5 alkylene)-O(Ci-5 alkyl), -(C0-3 alkylene)-SH, -(C0-3 alkylene)-S(Ci-5 alkyl), -(C0-3 alkylene)-S(Ci-5 alkylene)-SH, -(C0-3 alkylene)-S(Ci-5 alkylene)-S(Ci-5 alkyl), -(C0-3 alkylene)-NH2, -(C0-3 alkylene)-NH(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-OH, -(C0-3 alkylene)-N(Ci-5 alkyl)-OH, -(C0-3 alkylene)-NH-O(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-O(Ci-5 alkyl), -(C0-3 alkylene)-halogen, -(C0-3 alkylene)-(Ci-5 haloalkyl), -(C0-3 alkylene)-O-(Ci-5 haloalkyl), -(C0-3 alkylene)-CN, -(C0-3 alkylene)-NO2, -(C0-3 alkylene)-CHO, -(C0-3 alkylene)-CO-(Ci-5 alkyl), -(C0-3 alkylene)-COOH, -(C0-3 alkylene)-CO-O-(Ci-5 alkyl), -(C0-3 alkylene)-O-CO-(Ci-5 alkyl), -(C0-3 alkylene)-CO-NH2, -(C0-3 alkylene)-CO-NH(Ci-5 alkyl), -(C0-3 alkylene)-CO-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-CO-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-C0-(Ci-5 alkyl), -(C0-3 alkylene)-NH-C0-0-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-C0-0-(Ci-5 alkyl), -(C0-3 alkylene)-0-C0-NH-(Ci-5 alkyl), -(C0-3 alkylene)-0-C0-N(Ci-5 alkyl)-(Ci-5 alkyl), -(C0-3 alkylene)-SO2-NH2, -(C0-3 alkylene)-SO2-NH(Ci-5 alkyl), -(C0-3 alkylene)-SO2-N(Ci-5 alkyl)(Ci-5 alkyl), -(C0-3 alkylene)-NH-SO2-(Ci-5 alkyl), -(C0-3 alkylene)-N(Ci-5 alkyl)-SO2-(Ci-5 alkyl), -(C0-3 alkylene)-SO2-(Ci-5 alkyl), -(C0-3 alkylene)-S0-(Ci-5 alkyl), -(C0-5 alkylene)-carbocyclyl, and -(C0-5 alkylene)-heterocyclyl, wherein one or more -CH2- units in the alkylene moiety in said -(C0-5 alkylene)-carbocyclyl and/or in the alkylene moiety in said -(C0-5 alky lene)-heterocycly I are each optionally replaced by a group independently selected from -O-, -CO-, -CO-O-, -O-CO-, -NH-, -N(CI.₅ alkyl)-, -NH-CO-, -N(CI.₅ alkyl)-CO-, -CO-NH-, -CO-N(CI.₅ alkyl)-, -S-, -SO-, -SO₂-, -SO2-NH-, -SO₂-N(CI.₅ alkyl)-, -NH-SO2-, and -N(CI.₅ alkyl)-SO₂-, and further wherein the carbocyclyl moiety in said -(C0-5 alkylene)-carbocyclyl and the heterocyclyl moiety in said -(C0-5 alky lene)-heterocycly I are each optionally substituted with one or more groups independently selected from C1-5 alkyl, C2-5 alkenyl, C2-5 alkynyl, -OH, -O(Ci-5 alkyl), -O(Ci-5 alkylene)-OH, -O(Ci-5 alkylene)-O(Ci-5 alkyl), -SH, -S(Ci.₅ alkyl), -S(Ci.₅ alkylene)-SH, -S(Ci.₅ alkylene)-S(Ci.₅ alkyl), -NH₂, -NH(CI.₅ alkyl), -N(CI.₅ alkyl)(Ci-₅ alkyl), -NH-OH, -N(CI.₅ alkyl)-OH, -NH-O(CI.₅ alkyl), -N(CI.₅ alkyl)-O(Ci.₅ alkyl), halogen, C1.5 haloalkyl, -O-(Ci.₅ haloalkyl), -CF₃, -ON, -NO₂, -OHO, -CO-(Ci.₅ alkyl), -COOH, -CO-O-(Ci.₅ alkyl), -O-CO-(Ci-5 alkyl), -CO-NH₂, -CO-NH(CI.₅ alkyl), -CO-N(CI.₅ alkyl)(Ci.₅ alkyl), -NH-CO-(CI.₅ alkyl), -N(CI-₅ alkyl)-CO-(Ci.₅ alkyl), -NH-CO-O-(CI.₅ alkyl), -N(CI.₅ alkyl)-CO-O-(Ci.₅ alkyl), -O-CO-NH-(CI.₅ alkyl), -O-CO-N(CI-5 alkyl)-(Ci.₅ alkyl), -SO2-NH2, -SO₂-NH(CI.₅ alkyl), -SO₂-N(CI.₅ alkyl)(Ci.₅ alkyl), -NH-SO2-(CI-5 alkyl), -N(CI-5 alkyl)-SC>2-(Ci-5 alkyl), -SO2-(Ci-5 alkyl), -SO-(Ci-5 alkyl), cycloalkyl, and heterocycloalkyl; and n' and n” are each independently selected from 0, 1, 2, 3, and 4.

14. The biosensor of claim 13, wherein the boronic acid-based glucose-binding moiety comprises a moiety of formula (lc-1):

wherein:

R^L, R^s, n' and n” are as defined in claim 6;

R¹ is a group -CONH-CH2CH2-(O-CH2CH2)_m-, wherein m is an integer in the range from 1 to 10, or a group -CH2-arylene; wherein R¹ is attached via its terminal -CH2- group to the nitrogen atom in formula (lc-1); and R² is a group -CH2-CONH-(CH2CH2O)_P-(CI-5 alkyl), C1-5 alkyl, -(C0-3 alkylene)-aryl, or -(C0-3 alkylene)- heteroaryl, wherein p is an integer in the range from 1 to 10, wherein the aryl in said -(C0-3 alkylene)-aryl and the heteroaryl in said -(C0-3 alkylene)-heteroaryl are each optionally substituted with one or more R^s; wherein it is preferred that n' and n” are each 0, and/or that R^L is -(CH2)e-.

15. The biosensor of claim 13 or 14, wherein the inhibitor moiety comprises a moiety of the following formula (He):

(He), and wherein the boronic acid-based glucose-binding moiety and the inhibitor moiety are present in a molar ratio of about 1 :1 ; wherein the inhibitor moiety comprises a moiety of the following formula (lib):

and wherein the boronic acid-based glucose-binding moiety and the inhibitor moiety are present in a molar ratio of from about 2:1 to about 1 :3; preferably wherein the boronic acid-based glucose-binding moiety and the inhibitor moiety are present in a molar ratio of from about 1 :1 to about 1 :3, more preferably wherein the boronic acid-based glucose-binding moiety and the inhibitor moiety are present in a molar ratio of 1 :1 to 1 :2, even more preferably wherein the boronic acid-based glucose-binding moiety and the inhibitor moiety are present in a molar ratio of about 1 :2.

16. The biosensor of claim 1, wherein the boronic acid-based glucose-binding moiety comprises a moiety of formula (lc-1):

(lc-1) wherein: n' and n” are each 0; R¹ is a group -CONH-CH2CH2-(O-CH2CH2)_m- or a group -CH2-arylene, wherein R¹ is attached via its terminal -CH2- group to the nitrogen atom in formula (lc-1 ); m is an integer in the range from 1 to 10, preferably m is selected from 2, 3, 4, 5, and 6, more preferably m is 4;

R^L is -(CH2)e-; and wherein the inhibitor moiety comprises a moiety of formula (lib):

wherein the boronic acid-based glucose-binding moiety and the inhibitor moiety are present in a molar ratio of from about 1 :1 .5 to about 1 :2.5, preferably about 1 :2.

17. The biosensor of claim 16, wherein the polymer is obtainable in a polymerization reaction of a composition comprising:

and

18. The biosensor of any one of claims 1 to 17, wherein the polymer is a polymeric hydrogel.

19. The biosensor of any one of claims 1 to 18, wherein the polymer is obtainable in a polymerization reaction of a composition comprising:

(ii) an acrylamide monomer comprising the inhibitor moiety, preferably wherein the composition used in the polymerization reaction further comprises:

(iv) a crosslinker acrylamide monomer; wherein it is preferred that:

- the acrylamide monomer (I) constitutes between 6 and 10 mol% of the acrylamide-based components in said composition, wherein the acrylamide monomers (I) and (ii) are present in a molar ratio of about 1 :1; and/or

- the acrylamide monomer (I) is selected from

- the acrylamide monomer (ii) is selected from

- the acrylamide monomer (ill) is selected from:

an integer from 2 to 5, more preferably wherein q is 2 or 5; and/or

- the crosslinker acrylamide monomer (iv) is selected from:

20. The biosensor of any one of claims 1 to 19 for use in an in vivo diagnostic method.

21. The biosensor of any one of claims 1 to 19 for use in an in vivo method of glucose monitoring, preferably wherein the glucose monitoring is performed on a subject that is under intensive care and/or that is unconscious.

22. The biosensor of any one of claims 1 to 19 for use in an in vivo method of diagnosing hyperglycemia or hypoglycemia.

23. Use of the biosensor of any one of claims 1 to 19 for measuring the glucose concentration in a sample.

24. A polymer as defined in any one of claims 1 to 19.