DE102009025073A1 - Optical sensor - Google Patents

Abstract

An optical sensor has a channel (110) and an optical waveguide (120). The channel (110) has opposite side walls (112a, 112b) connected by a bottom (114). The optical waveguide (120) is formed along the opposite sidewalls (112a, 112b) and along the bottom (114) such that light (130) creates an evanescent field (132) in the channel (110) as it passes the optical waveguide (120) Molecules (140) in the channel (110) are detectable by an interaction with the evanescent field (132).

Description

The The present invention relates to an optical sensor and to a method for producing an optical waveguide for an optical sensor and in particular an arrangement for guiding light.

specially in the field of application of diagnosis and analysis of sera or general sample media to be tested in biology, in biochemistry or in In chemistry, increasingly miniaturized components are being developed or used, which is a combination of functional elements include.

The Miniaturization in the field of biological, chemical, biochemical or environmental sensors or analysis modules becomes all the more interesting, the higher the quality of the reagents to be processed, or the fewer reaction sera to use. For High quality reagents can be used to save money realize the reagent volume. If only little reaction sera to In addition, miniaturization is a minimization reach the required sample volume. Also important is the elimination of external contamination, for example through a completely self-contained system, as well as the Reduction of potential sources of error and the influence of the operator on the (bio) chemical test. This will allow the tests performed outside of specialized laboratories which in turn leads to cost savings. Furthermore should the analysis modules also inexpensive to produce be.

a Great contribution to miniaturization can be the integration of functionalities on a substrate that continues in a system is installed. Such systems are for example as Microanalysis system or lab-on-chip arrangements known. here we can z. As integrated electro nic, optical and microfluidic elements become.

Various microfluidic modules with microchannels and functional elements are known in the art. EP 0938660 describes an example of a small reaction chamber with a fluid channel in which the light is passed directly through the reaction channel. Biosensors are also known which measure the absorption of biomolecules or marker molecules by means of optical waveguides (optical waveguides) or, alternatively, excite their fluorescence. Other conventional sensors are used for environmental technology by causing pollutants such as dissolved ions, salts, organic substances or metals on a reactive surface, a color change and thus are detectable. In so-called evanescent field techniques, the light is continuously guided in an optical waveguide and only interacts with the biomolecules via its evanscent field. The evanescent field corresponds to those components of the electric field of the light wave, which protrudes from the waveguide. The biomolecules can be immobilized, for example, in a microfluidic channel and brought into contact there with reagents. An example of such a system is in DE 10350526 A1 described. The principle to use evanescent optical fields in immunoassay sensors, for example, in DE 69429262 and EP 0959343 described.

A the difficulty in realizing the integration of an optical Waveguide with a fluid channel and the derived construction an evanescent field optical sensor for the detection of biomolecules lies in bringing the light in as efficiently as possible to interact with the biomolecules. Both Conventional systems often become planar Waveguide used on the one (angular) microfluidic channel is put on. The biomolecules are on the one hand in the fluid channel Mostly immobilized on all sides, the light o the evanescent On the other hand, field occurs only on one side of the fluid channel interact with the immobilized biomolecules, leaving a number of potential immobilized biomolecules not included in the measurement. This is limited in turn, the sensitivity of the sensor.

outgoing from this prior art, the present invention is the Task is to create a biosensor in which the interaction the light with the immobilized biomolecules clearly is increased.

These The object is achieved by the optical sensor according to claim 1 and a A method of forming an optical waveguide according to claim 11 solved.

Of the The present invention is based on the finding that an optical Sensor has a waveguide, not only along a Bottom of the microfluidic channel is formed, but at the same time along the opposite side walls extends. This becomes a high interaction intensity evanescent field with immobilized molecules achieved because the light propagating through the waveguide both over the side walls and over interact with the soil with immobilized molecules in the channel can. As fluid comes, for example, a liquid or a gaseous substance in question, which in a channel at the reactive Surface can be passed and the the carries with it the substance to be detected.

One Another core idea of the present invention is that the waveguide extending around the channel by a radiation treatment a substrate can be generated. For example, by means of a (UV) irradiation of the surface of the substrate Waveguide can be formed along the surface. The irradiation can, for example, by means of a UV laser or a CO2 laser. At the same time, the laser can also be used to form the channel in the substrate (e.g., by ablation), by changing parameters of the exemplary laser.

One important aspect is the appropriate choice of material for the substrate, making the irradiation a change the refractive index leads. For example, polycarbonate be used, which in a suitably chosen Irradiation a region with a higher refractive index formed. The region with the increased refractive index serves then as a waveguide, as it leads to total reflections at the interface comes between the region and the remaining substrate part. The The present invention particularly utilizes the synergy effect that by a change in the irradiation (eg variation of the irradiation) Laser parameters) on the one hand, the channel itself can be formed (by Ablation of substrate material) and on the other hand, the waveguide is formed in a surface area.

embodiments thus deal with the above-described integration of microfluidic Channels and optical waveguides. To the desired Interaction of light with a larger number to allow biomolecules, as I said the fluid channel in a cross-sectional plane perpendicular to the flow direction surrounded on three sides by a material that is both a higher Refractive index as the liquid in the fluid channel as well a higher refractive index than the substrate material, in which the channel is embedded has. The high-breaking Layer thus acts as an optical waveguide, so that with their Help the evanescent field of light interact with the at (at least) three sides of the fluid channel immobilized biomolecules can be brought. For immobilization of biomolecules For example, a surface treatment of the fluid channel happen or a surface layer can be formed.

The Covering the fluid channel can, for example, by a flat plate or in other embodiments also with the help a structured lid, the another channel and / or waveguide contains. Alternatively, instead of the Cover two channel structures mirror-symmetrical one above the other be arranged so that the resulting fluid channel of all Sides (perpendicular to the flow direction of the medium) of the waveguide is surrounded. The channel thus passes through the waveguide therethrough.

The Penetration depth of the evanescent field into the microfluidic medium depends on the wavelength and the difference refractive indices of waveguide and fluid. typically, the penetration depth is some 100 nm. The penetration depth the evanescent field is slightly higher than the typical one Thickness of immobilized (biomolecular) sensor layers, for example some 10 nm.

at Further embodiments, the waveguide is to used in the fluid channel (especially near the canal walls) Arisen luminescence or fluorescent light using the evanescent field into the waveguide and to one Photodetector to transport. In this way, the emission of a substance to be detected are measured.

The Formation of the waveguide in the substrate is in further embodiments below Using a mask performed. This is defined by the mask the shape of the waveguide along a surface of the substrate and irradiation of the surface by means of laser or another radiation source can then be done over the entire area, for example. In further embodiments, the structuring of the channel is not performed by a laser, but for example, by a combination of these processes with others Processes such as a local doping of the substrate material for the production of waveguides. Alternatively, the Channels also by hot stamping or milling be formed. For example, in these channels a higher refractive layer deposited as a waveguide become. An advantage of the embodiments, which a Laser writing, however, is the generation of channels for microfluidic applications, where the channel cross-section has rounded corners.

The advantages of embodiments can be summarized as follows. First, the direct writing of waveguides results in a very simple process because no additional materials are placed on or in the substrate to make the waveguide. The latter happens, for example, in conventional sensors in which waveguides are inserted into previously formed channels. On the other hand, the waveguide can also be caused by the action of the write laser due to changes in the refractive index of the substrate material. Advantageous are the possible contactless processing of the substrate, as well as the independence of speci ellen geometries or topographies. Thus, for example, waveguides can be guided under topographical structures or even be produced on sloping surfaces. Embodiments thus exploit in particular the synergy resulting from the combination of the two possibilities described above, namely the laser ablation for the production of channels and the direct laser writing of waveguides. Opto-fluidic systems can thus be produced in a uniform processing, wherein the light guide to a channel structure z. B. an opto-sensor.

embodiments The present invention will be described below with reference to FIG the accompanying drawings explained in more detail. Show it:

1 a cross-sectional view through a fluid channel for a biosensor according to an embodiment of the present invention;

2 a further cross-sectional view of a combination of waveguide and fluid channel according to embodiments;

3 a schematic representation of the effect of the evanescent field on immobilized molecules along the channel walls;

4 a cross-sectional view of two superimposed channel structures; and

5 a cross-sectional view of a substrate made of polycarbonate with a trained waveguide.

In terms of the following description should be noted that at the same embodiments or the same functionally identical functional elements have the same reference numerals and thus the description of these functional elements in the various Embodiments is interchangeable.

1 shows a cross-sectional view of an optical sensor with a channel 110 with opposite side walls 112a . 112b passing through a floor 114 are connected. Further, a waveguide 120 along the opposite side walls 112 and along the floor 114 trained so that light 130 when passing the waveguide 120 an evanescent field 132 in the canal 110 generated. molecules 140 are in the channel 110 through an interaction with the evanescent field 132 detectable. The molecules 140 For example, in a medium 150 be solved, the medium 150 For example, blood serum or water or other organic liquid may be included. Alternatively, the medium 150 also be a gaseous substance, so that the optical sensor can perform environmental analyzes, for example. In the first case, the molecules to be detected are 140 For example, biomolecules (or specific proteins), and in the latter case, the molecules include, for example, environmental pollutants in the aquatic environment, in the air or in exhaust gases from industrial plants.

Because the waveguide 120 the channel 110 encloses a large area, can with the geometry shown a larger number of biomolecules 140 with the light 130 Interact. Compared to conventional sensors, where the waveguide is in contact with the channel from one side only, the detection sensitivity is increased.

The in the 1 shown light guide (in the cross-sectional plane) is just one example. Alternatively, the light can 130 also perpendicular to the cutting plane (drawing plane) are performed. In this case, too, the evanescent field is formed 132 at the canal walls.

As already described, such a structure with the channel 110 and the waveguide 120 also be realized by a direct laser writing (for example in polycarbonate). Starting from a planar substrate of polycarbonate, under irradiation (eg exposure to ultraviolet laser light), both material is removed and thus the fluid channel is formed, as well as an increase in the refractive index of the polycarbonate at the processed boundary layer , The region of increased refractive index thus results in the formation of an optical waveguide at the interface between channel and substrate. Thus, by choosing optimal parameters in laser processing, either ablation ablation or refractive index conversion without erosion can be preferred. For example, the wavelength, the pulse duration, the pulse repetition rates, the pulse energy or by focusing the pulse energy density, the average power and the power density are available as selectable parameters of the exemplary laser. On the part of the material parameters, the absorption, the heat conduction, the heat capacity, the heat of vaporization and the effectiveness for the conversion of the refractive index can be optimized. In addition to polycarbonate other plastics can be used in further embodiments. In principle, any plastic which shows a change in the refractive index upon irradiation and is sufficiently transparent to a waveguide is suitable. This effect is also known for PMMA (polymethyl methacrylate, Plexiglas), so that alternatively PMMA, doped glasses or other materials can be used as substrate material.

2 shows an embodiment of a combination of waveguides 120 and fluid channels 110 to a micro-opto-fluidic system, wherein the sectional view shown along a fluid channel 110 is shown. The micro-opto-fluidic system has a substrate 160 on, in which the fluid channel 110 is formed as a recess and the waveguide 120 the fluid channel 110 both along the ground 114 as well as along the opposite side walls 112a . 112b limited. In addition, the shows 2 that the fluid channel 110 through a lid 170 is closed, leaving the fluid channel 110 forms a cavity in which the medium 150 with the molecules 140 can spread.

The light 130 is for example via an optical input 131 coupled into the micro-fluidic system and via an optical output 133 decoupled, wherein the light supply / discharge can be done by means of another waveguide (not shown). The supplied light 130a then passes along the waveguide 120 to the channel 110 , where in the channel 110 the evanescent field 132 along the canal walls 112 and the soil 114 out forms. The evanescent field 132 can then, for example, with the molecules 140 , For example, which are immobilized on the channel wall, interact, so that the dissipated light 130b has a different characteristic than the supplied light 130a , From the change between the supplied light 130a and the discharged light 130b It is possible to interact with the immobilized molecules 140 to detect. To the light guide along the waveguide 120 To facilitate, the opposite side walls can 112a . 112b sloping so that they are not right angles with the ground 114 but at an acute angle (eg, less than 45 ° or less than 60 °) to this run. This makes it possible for the light to come out of the ground as a result of total reflection 114 in the sidewall 112 is directed. For this it is advantageous if the difference of the refractive indices between the substrate 160 and the waveguide 120 as big as possible. The substrate 160 may for example comprise polycarbonate or PMMA.

In further embodiments, the waveguide 120 used in the fluid channel 120 (Especially near the channel walls) incurred luminescence 130c (Fluorescent or phosphorescent light) in the waveguide 120 to be coupled in and transported to a photodetector (not shown). The coupling can in turn with the help of the evanescent field 132 happen. In this way, the emission of a substance to be detected can be measured. To stimulate the luminescence, for example, the medium 150 be excited by an external radiation source (not shown), wherein the excitation radiation, for example, a different wavelength than the luminescence and thus can be filtered out.

3 shows a cross-sectional view through a fluid channel 110 along the section line 2-2 'of the optical waveguide 120 is surrounded. In the fluid channel 110 are molecules to be detected 142 (eg, analyte molecules) in the fluid 150 solved. Along the side walls 112 are the immobilized analyte molecules 140 that with the evanescent field 132 the waveguide modes (the normal component with respect to the waveguide surface) interact. This interaction can, for example, be an absorption of the evanescent waveguide modes 132 and the "leak rate" caused thereby can be detected from the transmitted light. In the exemplary embodiment shown, the light propagation takes place, for example, perpendicular to the plane of the drawing (see section line 2-2 'in FIG 2 ).

The said change between the supplied light 130a and the discharged light 130b as a result of the interaction of the evanescent field 132 with the immobilized molecules 140 may include, for example, a color change when the immobilized analyte molecules 140 a certain frequency component of the transmitted light 130 absorb. In the simplest case, however, only the intensity of the transmitted light 130 as a result of the absorption of the evanescent field change. However, it is also possible that the molecules 140 be excited to fluorescence and even emit light which can be detected. The transmitted light 130 For example, monochromatic light generated by a laser may be. The wavelength of the light used can to the molecules to be detected 140 be adjusted so that during operation also light 130 different wavelength (successively) for the detection of different molecules 140 can be used.

To the analyte molecules 140 on the canal wall 112 to immobilize, optionally an immobilization layer 240 (Sensor layer) on the channel wall 112 and / or soil 114 be educated. The immobilization layer 240 For example, it may contain reagents that are sensitive to certain analyte molecules 140 are, so these particular analyte molecules 140 preferably on the channel wall 112 and / or soil 114 be immobilized or dock easily. This reaction with the reagents can cause optical properties of the immobilization layer 240 change, then targeted by means of the evanescent field 132 can be detected. Thus, it is possible, for example, specifically the sensitivity for certain analyte molecules that occur, for example, only in a very low concentration to increase. The immobilization layer 240 For example, it may be designed such that the immobilized analyte molecules 140 have a layer thickness, the penetration depth of the evanescent field 132 in the channel 110 equivalent. As already mentioned above, the penetration depth of the evanescent field is for example a few 100 nm (for example in the range between 50 nm and 1 mm or in the range between 100 nm and 400 nm). To ensure the most efficient penetration of the immobilized analyte molecules 140 can reach the described sensor layer 240 for example, have a thickness d of 10 nm or in a range between 1 nm and 100 nm or between 5 nm and 100 nm or in a range between 10 nm and 50 nm. The extent of the canal 110 perpendicular to the flow direction (= transverse expansion) of the fluid 150 For example, it may be chosen such that the fluid 150 due to capillary forces in the canal 110 flows in, for. For example, the maximum transverse extent may be less than 3 mm or less than 1 mm (or <50 μm, <100 μm, <500 μm).

The medium 150 can through the channel 110 either flow or be at rest, so that sufficient time is available to allow the molecules to be detected 140 on the canal wall 112 can knock down. The flow rate may also be selected such that as many analyte molecules as possible 140 on the canal wall 112 can dock.

For example, along the line 3-3 ', the lid 170 from the 2 or a plate can be arranged, the lid 170 for example, a glass plate can be. Alternatively, the lid 170 be structured so that the lid 170 also a light guide at its the channel 110 facing side has. Optionally, however, it is also possible to use two channel structures as shown in FIG 3 are shown along the line 3-3 'mirror-symmetrical to each other.

4 shows an embodiment in which as mentioned two channel structures, as shown in the 3 are connected together along the line 3-3 '. Accordingly, in the embodiment in the 4 the channel 110 on the one hand by a first light guide 120a and on the opposite side by a second optical fiber 120b laterally limited. The first light guide 120a is in a first substrate 160a and the second light guide 120b in a second substrate 160b educated. The first substrate 160a has a recess on the part of the channel 110a forms and on the surface of the first light guide 120a is formed, so that the first light guide 120a the first channel part 110a limited. In the same way, the second substrate 160b a recess on which the second part of the channel 110b forms, again between the second part of the channel 110b and the second substrate 160b the second light guide 120b is trained. The first and second part of the canal 110a , b become the channel 110 combined, for example, all the way through the waveguide 120 (ie, the first and second optical fibers 120a , b) is bordered.

The light guide in the embodiment, as it is in 4 For example, it may be parallel to the direction of flow in the channel 110 take place (for example, perpendicular to the plane), in turn, the fluid 150 in the channel 110 the analyte molecules 140 which now has channel walls 112 both light guides 120a , b can knock down. Alternatively, it is also possible to choose the light guide such that the light 130 perpendicular to the flow direction in the channel 110 spreads. This can be achieved, for example, in that feeds and discharges for the light are formed along the line 3-3 '(as in FIG 1 shown).

By the channel 110 completely through the waveguide 120 is enclosed, as it is in the embodiment of 4 If this is the case, all biomolecules immobilized on the channel surfaces will come into contact with the evanescent field. Thus, at the same time, the interaction possibilities with the immobilized analyte molecules 140 along the canal walls 112 and maximize sensitivity. The diameter of the channel 110 or the maximum extent of the channel 110 For example, it can be chosen so small that the evanescent field 132 the channel cross section (in the sectional plane of the 4 ), so that all the analyte molecules in the medium 150 with the evanescent field 132 can interact. However, in order to achieve the advantageous effect of the optical sensor, it is often sufficient if only the molecules bound to the channel wall are detected. The cross section of the canal 110 may for example be oval or elliptical, circular or square or rectangular. However, in order to achieve efficient light guidance with as few losses as possible (eg due to scattering in the substrate 160 ) along the waveguide 120 To achieve it is advantageous if the waveguide 120 has as little or no inclinations or curvatures along the light guide or the light propagation. Therefore, it may be advantageous if the light guide parallel to the flow direction of the medium 150 is selected. As described above, from a comparison of the supplied light 130a and the derived light 130b on the absorption of the evanescent field 132 be closed, again either color changes or intensity changes are detectable.

The first and second substrate 160a , b and the first and second light guides 120a For example, b may initially be formed of a same material, with the first and second light guides 120a , b, for example, by a laser treatment on the surface of the substrate 160 can be formed. Alternatively, the waveguide 120 also be generated by an irradiation with light of a specific wavelength (eg UV light), wherein the intensity and the wavelength of the light used are chosen so that the refractive index of the material changes in the Einstrahlbereich. For example, this material may comprise polycarbonate or PMMA. By changing the refractive index by means of irradiation within the waveguide region 120 changes the material compared to the substrate 160 his optical behavior.

The 5 shows an embodiment, such as a light guide 120 on a surface of a substrate 160 can be trained. This is the substrate 160 For example, irradiated with light of a certain wavelength, wherein the wavelengths in the ultraviolet, visible or infrared spectral range may be. Alternatively, an irradiation z. B. be used by a laser for waveguide generation. If the substrate material is chosen properly, this will cause the refractive index of the material in the irradiated region to change as a result of absorption of the electromagnetic energy. As this change only happens locally in the irradiated region, it becomes a waveguide 120 trained in the irradiated region. There is no extra waveguide layer applied - the waveguide is formed rather from the substrate material.

The generated waveguide can basically be characterized in that it has a different refractive index compared to its surroundings (non-irradiated substrate material), so that light which is coupled into the waveguide as parallel to the longitudinal extent of the waveguide as possible due to total reflections at the edge of the waveguide in Waveguide remains and is not emitted to the surrounding medium. This is basically the case when the waveguide has a more dense optical medium than the environment and further when the transition region is a reflection plane for light so that the light preferably propagates in the waveguide. The advantage of the described materials, such as polycarbonate or PMMA is precisely that they are both transparent and on the other hand increase their refractive index at a suitably selected irradiation. Like in the 5 As shown, this may be a surface area of a substrate 160 correspondingly as a waveguide 120 being transformed. However, this method is not only useful for forming waveguides along channel structures, such as the biosensors described above, but can also be used to form, for example, optical interconnects for film systems or for smart cards or other opto-electronic devices.

polycarbonate (PC) shows when compared to PMMA when working with a laser a different behavior. For example, it is possible with a UV laser ablation (= sudden evaporation) to form use of depressions and trenches, taking the walls have a smooth structure when using polycarbonate. By contrast, the walls of PMMA exhibit in use of laser radiation, for example, bubbles in the interior of the material resulting in a foamy surface. The strength of this effect, however, depends on the used wavelength. This leads, for example to the fact that in PMMA the surface is no longer flat, but the irradiated region stands out from the substrate. This effect does not occur in polycarbonate or much less on. Even if this behavior by controlling the acting Radiation is controllable, so that the degree of foamy surface regulates, there is an essential advantage of the Polycarbonate in that this material is not to the said Blistering tends. The differences between polycarbonate and PMMA are also in the different material constants such as absorption coefficient and penetration depth the laser wavelength used, thermal output, Heat capacity, heat of fusion and heat of vaporization of the material. Here, each material-wavelength combination behaves different. Polycarbonate is also characterized by a favorable chemical behavior towards liquid, biological Samples and is therefore preferred. Also in the aging resistance and the mechanical stability is polycarbonate over PMMA in advantage.

For example, a laser may be used for the irradiation which, for example, emits UV light having a wavelength of approximately 355 nm. This laser can be used both for ablation and thus for the formation of the canal 110 as well as to convert the surface area into a waveguide. As an alternative to the UV laser with about 355 nm, it is also possible to use a CO ₂ laser with a wavelength of about 10.6 microns, which also provides the desired effect. Therefore, when using polycarbonate, irradiation with light (or general electromagnetic radiation) in a wide wavelength range is possible (from 200 nm to, for example, 20 μm). To change the material properties is mainly the amount of absorbed energy, and if this be a be exceeds threshold, the conversion to a waveguide will work within a very broad frequency spectrum. Therefore, depending on the substrate material and the radiation used can be optimized. As mentioned, it is also possible to produce the waveguide in an inner substrate region (in the depth of the substrate), for example, by intersecting rays or by high-aperture interior focusing.

Embodiments of the present invention can thus be summarized as follows. They include an optical sensor with a channel 110 at least partially with an optical waveguide 120 is wrapped. The optical sensor can optionally be on the surface 112 immobilized biological or chemical molecules, a change in the light in the adjacent waveguide 120 cause. In further embodiments, the change of the light takes place 130 in the waveguide 120 by absorption of the evanescent field 132 of the waveguide 120 or by a coupling of fluorescent light into the waveguide. The optical sensor is designed to either the absorption of the evanescent field 132 or the coupled fluorescent light 130c in the waveguide 120 to detect. Optionally, the evanescent field can also excite the fluorescence of the biomolecules, the fluorescent light then being otherwise detected. In further embodiments, the sensor for the detection of chemical or biological substances in a liquid or gaseous fluid 150 used. Further exemplary embodiments likewise include a method for producing the sensor by means of a laser or by means of UV light.

In further embodiments, the light 130 at the edge of the lab-on-chip by means of a glass fiber into a waveguide 120 coupled and from this to the fluid channel 110 continued. There is the light 130 due to the distribution of refractive index around the channel 110 guided around, with the evanescent field 132 the guided waveguide modes with the liquid 150 (or the gas) in the fluid channel 110 with at the canal walls 112 immobilized (bio) molecules 140 interacts. The remaining light 130b can be taken and analyzed using a similar construction on the other side.

Because the medium 150 is either liquid or gaseous, impurities are also detectable for example in the air or in exhaust gases or wastewater. The sensor can therefore be used to measure air pollution within urban areas. Other components such as pollen can also be detected in the air. It is also possible to use the sensor for biological investigations in order to measure, for example, specific analyte molecules or proteins which can provide an indication of specific diseases (eg markers) with high precision.

at Further embodiments are waveguides in polycarbonate by direct writing using UV radiation (eg Laser irradiation) independently of a biosensor used. such Waveguides have a wide potential range of applications, such as the optical connection in film systems or smart cards.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• EP 0938660 [0005]
• - DE 10350526 A1 [0005]
• - DE 69429262 [0005]
• EP 0959343 [0005]

Claims (14)

Optical sensor with: a channel ( 110 ) with opposite side walls ( 112a . 112b ) passing through a floor ( 114 ) are connected; and an optical fiber ( 120 ), along the opposite side walls ( 112a . 112b ) and along the ground ( 114 ), so that light ( 130 ) when passing the optical waveguide ( 120 ) an evanescent field ( 132 ) in the channel ( 110 ) and molecules ( 140 ) in the channel ( 110 ) by an interaction with the evanescent field ( 132 ) are detectable. An optical sensor according to claim 1, wherein the opposite side walls ( 112a . 112b ) an immobilization layer ( 240 ) and the immobilization layer ( 240 ) is adapted to the molecules ( 140 ) by interaction with reagents. An optical sensor according to claim 2, wherein the evanescent field ( 132 ) into the channel ( 110 ) is measurable to a penetration depth and in which the immobilization layer ( 140 ) has a layer thickness (d) smaller than the penetration depth. Optical sensor according to one of the preceding claims, in which the channel ( 110 ), a medium ( 150 ) in the flow direction and in which the optical waveguide ( 120 ) perpendicular to the flow direction of the medium ( 150 ) around the canal ( 110 ) is formed around. An optical sensor according to any one of the preceding claims, further comprising a cover ( 170 ) and the cover has a boundary along the opposite ( 114 ). Optical sensor according to one of the preceding claims, in which the optical waveguide ( 120 ) has a transparent plastic which changes its refractive index when irradiated. An optical sensor according to claim 6, further comprising a substrate ( 160 ) of the transparent plastic, wherein the optical waveguide ( 120 ) has a higher refractive index as a result of irradiation than the substrate ( 160 ). An optical sensor according to claim 6 or claim 7, wherein the transparent plastic comprises polycarbonate or PMMA. Optical sensor according to one of the preceding claims, in which the channel ( 110 ) and the optical fiber ( 120 ) are formed so that the evanescent field ( 132 ) enters the channel in an angular range of more than 150 °. An optical sensor according to any one of the preceding claims, further comprising a photodetector, the photodetector being adapted to detect a change in the intensity or spectral composition of the light ( 130 ) when passing the optical waveguide ( 120 ) to detect. Method for producing an optical sensor, comprising: providing a substrate ( 160 ) made of glass or a transparent plastic, which changes its refractive index when irradiated; Forming a channel ( 110 ) with opposite side walls ( 112a . 112b ) passing through a floor ( 114 ) are connected; and generating an optical waveguide ( 120 ) along the opposite side walls ( 112a . 112b ) and along the ground ( 114 ), so that light ( 130 ) when passing the optical waveguide ( 120 ) an evanescent field ( 132 ) in the channel ( 110 ) and molecules ( 140 ) in the channel ( 110 ) by an interaction with the evanescent field ( 132 ) are detectable, wherein the optical waveguide ( 120 ) by means of an irradiation or a doping which determines the refractive index of the substrate ( 160 ) is generated. Method according to claim 11, wherein the forming of the channel ( 110 ) is performed by ablation by means of a further irradiation, wherein the further irradiation differs from the irradiation in terms of intensity, wavelength, pulse rate or pulse length. Method according to one of claims 11 to 12, wherein the steps of forming the channel ( 110 ) or the step of generating the optical waveguide ( 120 ) a use of a mask that matches the shape of the channel ( 110 ). Method for producing an optical sensor structure, comprising the following steps: producing a first optical sensor according to one of Claims 11 to 13 with a first optical waveguide ( 120a ), which has a first channel part ( 110a ) limited; Producing a second optical sensor according to one of Claims 11 to 13 with a second optical waveguide ( 120b ), which has a second channel part ( 110b ) limited; and arranging the first and second optical sensors one above the other such that the first and second channel parts ( 110a . 110b ) to a channel ( 110 ) and the first and second optical fibers ( 120a . 120b ) face each other.