HK40028757B - Flow cells with hydrogel coating - Google Patents

Description

Flow cell with hydrogel coating

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. provisional application serial No. 62/609,105 filed on 21.12.2017, the contents of which are incorporated herein by reference in their entirety.

Background

Bioarrays are one of the broad tools used to detect and analyze molecules, including deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). In these applications, the arrays are engineered to include probes to nucleotide sequences present in genes of humans and other organisms. In some applications, for example, individual DNA and RNA probes may be ligated at locations in a geometric grid (or randomly) on an array support. A test sample, e.g., from a human or organism, can be exposed to the grid such that complementary fragments hybridize to probes at individual sites in the array. The array can then be examined by scanning light at a particular frequency over the sites to identify which fragments are present in the sample by fluorescence of the sites to which the fragments hybridize.

Bioarrays can be used for gene sequencing. Typically, gene sequencing involves determining the order of nucleotides or nucleic acids in a length of genetic material (e.g., a DNA or RNA fragment). Increasingly long base pair sequences are being analyzed and the resulting sequence information can be used in various bioinformatic approaches to logically assemble fragments together to reliably determine the extensive length of the sequence of the genetic material from which the fragments were generated. Automated, computer-based detection methods of characteristic fragments have been developed and used for genome mapping, identification of genes and their functions, risk assessment of certain conditions and disease states, and the like. In addition to these applications, biological arrays can be used to detect and evaluate a wide range of molecules, molecular families, genetic expression levels, single nucleotide polymorphisms, and genotyping.

Disclosure of Invention

In a first aspect, a method includes applying a functionalized coating in recesses of a patterned flow cell substrate, wherein the recesses are separated by interstitial regions; grafting a primer onto the functionalized coating to form a grafted functionalized coating in the depression; and applying a hydrogel over the grafted functionalized coating.

In an example of this first aspect of the method, the hydrogel is selected from the group consisting of poly (N- (5-azidoacetamidylpentyl) acrylamide-co-acrylamide), cross-linked polyacrylamide, sepharose, and cross-linked polyethylene glycol.

In an example of this first aspect of the method, the hydrogel is disposed on a grafted functionalized coating. In one example, a hydrogel is applied over the functionalized coating and over at least some of the interstitial regions in the depressions. In another example, applying the hydrogel includes selectively disposing the hydrogel on the grafted functionalized coating in the depression.

In an example of this first aspect of the method, prior to applying the functionalized coating, the method further comprises treating the surface of the patterned flow cell substrate to attach functional groups to the surface, thereby forming treated recesses and treated interstitial regions. In this example, applying the functionalized coating in the recess includes: applying a functionalized coating in the treated recesses and on the treated interstitial regions; and polishing the functionalized coating from the treated interstitial layer.

In an example of this first aspect of the method, applying the hydrogel comprises applying an aqueous mixture comprising from about 0.001% up to about 0.1% (mass to volume) of the hydrogel material. In one example, the hydrogel material is selected from the group consisting of poly (N- (5-azidoacetamidylpentyl) acrylamide-co-acrylamide), crosslinked polyacrylamide, sepharose, and crosslinked polyethylene glycol.

In an example of this first aspect of the method, the perimeter of the patterned flow cell substrate has a spacer layer bonded thereto, and after applying the hydrogel, the method further comprises bonding (bonded) a lid to the spacer layer.

In an example of this first aspect of the method, after applying the functionalized coating and before grafting the primers, the method includes bonding a cover to at least some of the interstitial regions.

In an example of this first aspect of the method, applying the hydrogel includes selectively depositing the hydrogel on the grafted functionalized coating. It will be appreciated that any features of this first aspect of the method may be combined together in any desired manner and/or configuration.

In a second aspect, a method includes attaching a silane or silane derivative to a surface of a patterned substrate, the substrate comprising a flow-through channel having recesses defined therein, wherein the recesses are separated by gap regions, thereby forming silanized recesses and silanized gap regions; applying a functionalized coating in the silanized depressions and on the silanized interstitial regions; polishing the functionalized coating from the silanized interstitial regions; grafting a primer onto the functionalized coating in the silanized depression to form a grafted functionalized coating in the depression; and applying a hydrogel to the grafted functionalized coating in the depression.

In an example of this second aspect, applying the hydrogel includes applying an aqueous mixture including from about 0.001% up to about 0.1% (mass to volume) of the hydrogel material. In this example, the hydrogel material is selected from the group consisting of poly (N- (5-azidoacetamidylpentyl) acrylamide-co-acrylamide), crosslinked polyacrylamide, sepharose, and crosslinked polyethylene glycol.

In an example of this second aspect, the spacer layer is joined to the patterned substrate and defines a periphery of the flow channel; and after applying the hydrogel, the method further comprises bonding the cover to the spacer layer.

In an example of this second aspect, after polishing the functionalized coating and before grafting the primers, the method further comprises bonding a cover to at least some of the interstitial regions.

In an example of this second aspect of the method, applying the hydrogel includes applying the hydrogel over the grafted functionalized coating in the depression. In one example, a hydrogel is applied over the functionalized coating and over at least some of the interstitial regions in the depressions. In another example, applying the hydrogel includes selectively depositing the hydrogel over the grafted functionalized coating.

It will be appreciated that any of the features of this second aspect of the method may be combined in any desired manner. Furthermore, it will be appreciated that any combination of features of this aspect of the method and/or the first aspect of the method may be used together, and/or any feature from either or both of these aspects may be combined with any of the examples disclosed herein.

In another aspect, a flow cell includes a patterned substrate including recesses separated by interstitial regions; a sequencing surface chemistry (sequencing surface chemistry) attached to each recess, the sequencing surface chemistry comprising: a functionalized coating, and a primer grafted to the functionalized coating; and a hydrogel on the sequencing surface chemistry and optionally on some of the interstitial regions.

In the example of a flow cell, the hydrogel is also on at least some of the interstitial regions.

In the example of a flow cell, the functionalized coating is poly (N- (5-azidoacetamidylpentyl) acrylamide-co-acrylamide).

In the example of a flow cell, the hydrogel is selected from the group consisting of poly (N- (5-azidoacetamidylpentyl) acrylamide-co-acrylamide), cross-linked polyacrylamide, sepharose, and cross-linked polyethylene glycol.

In the flow cell example, the hydrogel is not grafted to the surface chemistry.

In the example of a flow cell, the patterned substrate includes at least one flow channel; a recess is defined in the at least one flow channel; and the flow cell further comprises a spacer layer attached to the other gap region of the patterned substrate such that the spacer layer defines a perimeter of the at least one flow channel. In this example, the flow cell may further comprise a lid attached to the spacer layer.

It will be appreciated that any of the features of this aspect of the flow cell may be combined together in any desired manner. Furthermore, it will be appreciated that any combination of features of this aspect of the flow cell and/or the first and/or second aspects of the method may be used together, and/or any feature from any one aspect may be combined with any example disclosed herein.

Drawings

Features of examples of the present disclosure will become apparent by reference to the following detailed description and drawings, in which like reference numerals correspond to similar, but perhaps not identical, components. For the sake of brevity, reference numerals or features having a previously described function may or may not be described in connection with other drawings in which they appear.

FIG. 1 is a flow chart illustrating an example of a method disclosed herein;

FIG. 2 is a flow chart illustrating another example of the method disclosed herein;

3A-3G and 3A-3D, 3H and 3I are schematic cross-sectional views depicting respective examples of the methods disclosed herein;

FIG. 4 is a cross-sectional view of an example flow cell formed by the method shown in FIGS. 3A-3G and FIGS. 3A-3D, 3H, and 3I;

FIG. 5 is a graph illustrating the percentage of clusters (% PF) and the percentage of depressions/wells occupied by DNA template (% occupied) by the filter for blocks of comparative flow cells (tiles) (1-384 on the X-axis) without hydrogel coating and blocks of example flow cells including hydrogel coating (385-768 on the X-axis);

FIG. 6 is a graph of the percentage of clusters that pass through the filter (% PF) versus the template concentration (pM) for comparative flow cells and example flow cells including hydrogel coatings;

FIG. 7 is a graph of the percent (% PF) of clusters passing through the filter after removal of replica template versus the template concentration (pM) for comparative flow cells and example flow cells including hydrogel coatings; and

fig. 8A and 8B are graphs of mismatch rates for read 1(R1) (fig. 8A) and read 2(R2) (fig. 8B) after 150 sequencing cycles for the comparative flow cell and the example flow cell including the hydrogel coating.

Detailed Description

Flow cells are commonly used for sequencing operations, analysis, and other biological applications. The patterned flow cell may comprise a substrate or carrier having recesses defined therein or thereon; and the chemically and/or biologically active surface chemistry may be confined in the depressions. For example, surface chemistries include functionalized coatings and primers. In certain sequencing operations, after a primer is immobilized in a recess of a flow cell substrate, a sequencing template (including a portion complementary to the primer) can be introduced into the recess, and the sequencing template can then be amplified to produce identical copies of the sequencing template (a process referred to herein as cluster generation).

In the examples disclosed herein, the hydrogel (also referred to herein as a hydrogel coating) is included directly on the surface chemistry, i.e., on the functionalized coating and the primers. It has been found that hydrogel coatings can slow sequencing template seeding rates as clusters are generated. As a result, after one sequencing template is seeded into a recess, there is more time (than when no hydrogel is included) for the template to expand into larger clusters before any subsequent sequencing template has a chance to diffuse through the hydrogel and into the recess. This increases the number of wells that are seeded with a single sequencing template. In other words, this increases monoclonal clustering within a particular recess (i.e., multiple copies of one type of sequencing template are formed) and decreases polyclonal clustering within a particular recess (i.e., multiple copies of multiple types of sequencing templates are formed). The number of clusters that passed through the filter after removing duplicates can indicate an increased monoclonal cluster. In one example, the range of net PF% for the examples disclosed herein that include a hydrogel coating is about 2% to about 17% higher than the net PF% for the comparative examples that do not include a hydrogel coating.

The methods disclosed herein may be performed entirely at the wafer level, entirely at the die (die) level, partially at the wafer level, and/or partially at the die level. As an example of performing the process partially at the wafer and die level, the wafer may be used to start the process, which is then diced to form several dies, and the process may continue with each die. The ability to perform open wafer processing enables, at least in some instances, various metrology/analysis techniques for quality control and characterization. The patterned and surface modified wafer/substrate may be exposed to, for example, Atomic Force Microscopy (AFM), Scanning Electron Microscopy (SEM), ellipsometry, goniometry, scatterometry, and/or fluorescence techniques prior to bonding to form a flow cell. Alternatively, the combined flow cell may be exposed to these techniques. At the die level, the process can be performed on an open die or on an assembled flow cell (with closed flow channels).

It will be understood that the terms used herein have the ordinary meaning as is accorded to such terms, unless otherwise specified. Several terms used herein and their meanings are listed below.

The singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise.

The terms including, comprising, containing and forms of these terms are synonymous with one another and are intended to be equally broad.

The terms top, bottom, lower, upper, etc. are used herein to describe the flow cell and/or various components of the flow cell. It will be understood that such directional terms are not meant to imply a particular orientation, but are used to designate relative orientations between the components. The use of directional terms should not be construed to limit the examples disclosed herein to any particular orientation.

As used herein, "alkyl" refers to a straight or branched hydrocarbon chain that is fully saturated (i.e., does not contain double or triple bonds). The alkyl group may have 1 to 20 carbon atoms. Example alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, hexyl and the like. For example, the designation "C1-4 alkyl" indicates the presence of one to four carbon atoms in the alkyl chain, i.e., the alkyl chain is selected from the group consisting of methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl.

As used herein, "alkenyl" refers to a straight or branched hydrocarbon chain containing one or more double bonds. The alkenyl group may have 2 to 20 carbon atoms. Example alkenyl groups include ethenyl, propenyl, butenyl, pentenyl, hexenyl, and the like.

As used herein, "alkyne" or "alkynyl" refers to a straight or branched hydrocarbon chain containing one or more triple bonds. Alkynyl groups may have 2 to 20 carbon atoms.

As used herein, "aryl" refers to an aromatic ring or ring system (i.e., two or more fused rings sharing two contiguous carbon rings) containing only carbon in the ring backbone. When the aryl group is a ring system, each ring in the system is aromatic. The aryl group may have 6 to 18 carbon atoms. Examples of aryl groups include phenyl, naphthyl, azulenyl (azulenyl), and anthracenyl.

As used herein, the term "attached" refers to the state in which two objects are joined, secured, adhered, connected, or bonded to each other. The attachment may be mechanical or may be chemical. For example, the nucleic acid can be chemically attached to the functionalized coating by covalent or non-covalent bonds. Covalent bonds are characterized by the sharing of electron pairs between atoms. Non-covalent bonds are physical bonds that do not involve electron pair sharing and may include, for example, hydrogen bonds, ionic bonds, van der waals forces, hydrophilic interactions, and hydrophobic interactions.

The "azide" or "azido" functional group is defined as the-N₃。

As used herein, "bond region" refers to a region of a substrate to which another material is bonded, which may be, for example, a spacer layer, a cover, another substrate, or the like, or a combination thereof (e.g., a spacer layer and a cover). The bond formed at the bonding region may be a chemical bond (as described above) or a mechanical bond (e.g., using fasteners, etc.).

As used herein, "carbocyclyl" refers to a non-aromatic ring or ring system containing only carbon atoms in the backbone of the ring system. When the carbocyclyl group is a ring system, two or more rings may be joined together in a fused, bridged or spiro joined manner. The carbocyclyl group may have any degree of saturation provided that at least one ring in the ring system is non-aromatic. Thus, carbocyclyl includes cycloalkyl, cycloalkenyl and cycloalkynyl. The carbocyclyl group may have 3 to 20 carbon atoms. Examples of carbocyclic rings include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclohexenyl, 2, 3-dihydro-indene, bicyclo [2.2.2] octyl, adamantyl and spiro [4.4] naphthyl.

As used herein, the term "carboxylic acid" or "carboxy" as used herein refers to-c (o) OH.

As used herein, the term "cycloalkylene" denotes a fully saturated carbocyclic ring or ring system attached to the rest of the molecule through two points of attachment.

As used herein, "cycloalkenyl" or "cycloalkene" means a carbocyclic group or ring system having at least one double bond, wherein no ring in the ring system is aromatic. Examples include cyclohexenyl or cyclohexene and norbornenyl or norbornene. As also used herein, "heterocycloalkenyl" or "heterocycloalkene" refers to a carbocyclic ring or ring system having at least one heteroatom in the ring backbone with at least one double bond, wherein no ring in the ring system is aromatic.

As used herein, "cycloalkynyl" or "cycloalkyne" refers to a carbocyclic ring or ring system having at least one triple bond, wherein no ring in the ring system is aromatic. An example is cyclooctyne. Another example is bicyclooctyne. As also used herein, "heterocycloalkynyl" or "heterocycloalkyne" refers to a carbocyclic ring or ring system having at least one heteroatom in the ring backbone with at least one triple bond, wherein no ring in the ring system is aromatic.

As used herein, the term "deposition" refers to any suitable application technique (which may be manual or automated) and results in a change in surface characteristics. Generally, deposition can be performed using vapor deposition techniques, coating techniques, grafting techniques, and the like. Some specific examples include Chemical Vapor Deposition (CVD), spray coating (e.g., ultrasonic spray coating), spin coating, dip (dunk) or dip coating, doctor blade coating, puddle dispensing (blade dispensing), cast coating, aerosol printing, inkjet printing, and the like.

As used herein, the term "recess" refers to a discrete recessed feature in a patterned substrate having a surface opening completely surrounded by a gap region of the patterned substrate surface. The recess may have any of a variety of shapes at its opening in the surface, including, for example, circular, oval, square, polygonal, star-shaped (having any number of vertices), and the like. The cross-section of the depression taken normal to the surface may be curved, square, polygonal, hyperbolic, conical, angular, etc. For example, the recess may be a hole.

The term "each," when used in conjunction with a collection of items, is intended to identify a single item in the collection, but does not necessarily refer to each item in the collection. Exceptions may occur if explicit disclosure or context clearly dictates otherwise.

As used herein, the term "flow cell" is intended to mean a container having a chamber (i.e., a flow channel) in which a reaction can take place, an inlet for delivering a reagent to the chamber, and an outlet for removing the reagent from the chamber. In some examples, the chamber enables detection of a reaction occurring in the chamber. For example, a chamber may include one or more transparent surfaces that allow for optical detection of arrays, optically labeled molecules, etc. in the chamber.

As used herein, a "flow channel" may be a region defined between two bonded components that can selectively receive a liquid sample. In some examples, a flow channel may be defined between the patterned substrate and the lid, and thus may be in fluid communication with one or more recesses defined in the patterned substrate.

The term "functionalized coating" as referred to herein is intended to mean a semi-rigid material that is permeable to liquids and gases. The functionalized coating may be a hydrogel that swells upon absorption of liquid and shrinks upon removal of the liquid by drying. In the examples disclosed herein, the functionalized coating includes an azide/azide functional group that is reactive with an alkyne functional group. In one example, the functionalized coating is poly (N- (5-azidoacetamidylpentyl) acrylamide-co-acrylamide) (PAZAM).

As used herein, "heteroaryl" refers to an aromatic ring or ring system (e.g., two or more rings sharing two contiguous atoms) containing one or more heteroatoms (i.e., elements other than carbon) in the ring backbone, including, but not limited to, nitrogen, oxygen, and sulfur. Where the heteroaryl is a ring system, each ring in the system is aromatic. Heteroaryl groups may have 5-18 ring members.

As used herein, "heterocyclyl" means a non-aromatic ring or ring system containing at least one heteroatom in the ring backbone. The heterocyclic groups may be joined together in a fused, bridged or spiro-connected manner. The heterocyclyl group may have any degree of saturation provided that at least one ring in the ring system is non-aromatic. In ring systems, heteroatoms may be present in non-aromatic or aromatic rings. A heterocyclyl group may have 3 to 20 ring members (i.e., the number of atoms making up the ring backbone, including carbon and heteroatoms). In some examples, the heteroatom is O, N or S.

The term "hydrazine" or "hydrazino" as used herein refers to-NHNH₂A group.

The term "hydrazone" or "hydrazone group" as used herein meansGroup, wherein R_aAnd R_bAs defined herein.

As used herein, "hydrogel" refers to a three-dimensional polymer network structure composed of cross-linked polymer chains. The hydrogel is not water soluble or removable from the liquid to which it is exposed during the sequencing process.

As used herein, "hydroxy" or "hydroxy" refers to an — OH group.

As used herein, the term "interstitial regions" refers to regions in or on a substrate that separate depressions. For example, a gap region may separate one feature of an array from another feature of the array. Two features that are separated from each other may be discrete, i.e., lack physical contact with each other. In another example, a gap region may separate a first portion of a feature from a second portion of the feature. In many instances, the interstitial regions are continuous, while the features are discrete, e.g., as in the case of a plurality of apertures defined in an otherwise continuous surface. The separation provided by the gap region may be a partial or complete separation. The gap region may have a surface material that is different from the surface material of the features defined in the surface. For example, the array features can have coatings and primers in amounts or concentrations that exceed the amount and concentration of the interstitial regions present. In some examples, the coating and primers may not be present in the interstitial regions.

As used herein, "nitrile oxide" means "R_aC≡N⁺O^-"group, wherein R_aAs defined herein. Examples of the production of the nitrile oxide include by treatment with chloramine-T or by base-pairing of imidoyl chloride [ RC (Cl) ═ NOH]The effect of (a) is generated in situ from the aldoxime.

As used herein, "nitrone" meansGroup, wherein R₁、R₂And R₃May be R as defined herein_aAnd R_bAny one of them.

As used herein, "nucleotide" includes nitrogen-containing heterocyclic bases, sugars, and one or more phosphate groups. Nucleotides are monomeric units of a nucleic acid sequence. In RNA, the sugar is ribose, while in DNA, the sugar is deoxyribose, i.e., a sugar lacking a hydroxyl group present at the 2' position of ribose. The nitrogen-containing heterocyclic base (i.e., nucleobase) can be a purine base or a pyrimidine base. Purine bases include adenine (A) and guanine (G) and modified derivatives or analogs thereof. Pyrimidine bases include cytosine (C), thymine (T), and uracil (U), and modified derivatives or analogs thereof. The C-1 atom of the deoxyribose is bonded to the N-1 of the pyrimidine or the N-9 of the purine.

The term "flow cell substrate" or "substrate" refers to a support to which surface chemistry may be added. The term "patterned substrate" refers to a support in or on which the recesses are defined. The substrate may be a wafer, panel, rectangular sheet, die, or any other suitable configuration. The substrate is generally rigid and insoluble in aqueous liquids. The substrate may be inert to the chemicals used to modify the depressions. For example, baseThe base may be inert to the chemistry used to apply the functionalized coating, attach primers to the functionalized coating, apply the hydrogel, and the like. Examples of suitable substrates include epoxysiloxanes, polyhedral oligomeric silsesquioxanes (POSS) or derivatives thereof, glass and modified or functionalized glass, plastics (including acrylics, polystyrene and copolymers of styrene with other materials, polypropylene, polyethylene, polybutylene, polyurethane, polytetrafluoroethylene (such as from Chemours)) Cycloolefin/epoxy-olefin polymers (COP), e.g. from Zeon) Polyimide, etc.), nylon, ceramic/ceramic oxide, silicon dioxide, fused silica or silica-based materials (e.g., including at least 10% silicon dioxide), aluminosilicates, silicon and modified silicon (e.g., boron-doped p + silicon), silicon nitride (Si)₃N₄) Silicon oxide (SiO)₂) Tantalum pentoxide (TaO)₅) Or other tantalum oxides (TaO)_x) Hafnium oxide (HaO)₂) Carbon, metal, inorganic glass, and the like. The substrate may also be glass or silicon or POSS or derivatives thereof with a coating of tantalum oxide or another ceramic oxide on its surface.

As used herein, "plasma ashing" refers to a process of removing organic substances from a substrate by oxygen plasma. Products produced by plasma ashing can be removed using a vacuum pump/system. Plasma ashing can activate the substrate by introducing reactive hydroxyl or carboxyl groups.

As used herein, a "primer" is defined as a single-stranded nucleic acid sequence (e.g., single-stranded DNA or single-stranded RNA) that serves as a point of initiation of DNA or RNA synthesis. The 5' end of the primer may be modified to allow for a coupling reaction with the functionalized coating. The primer length can be any number of bases in length and can include a variety of non-natural nucleotides. In one example, the sequencing primer is a short strand of 20 to 40 bases.

Such as bookAs used herein, the terms "silane" and "silane derivative" refer to organic or inorganic compounds containing one or more silicon atoms. An example of an inorganic silane compound is SiH₄Or halogenated SiH in which hydrogen is replaced by one or more halogen atoms₄. Examples of organosilane compounds are X-R^B-Si(OR^C)₃Wherein X is an organic group, e.g. amino, vinyl, methacrylate, epoxySulfur, alkyl, alkenyl, or alkynyl; r^BIs a spacer, e.g., - (CH)₂)_n-, where n is 0 to 1000; r^CSelected from hydrogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted carbocyclyl, optionally substituted aryl, optionally substituted 5-10 membered heteroaryl, and optionally substituted 5-10 membered heterocyclyl, as defined herein. The terms "silane" and "silane derivative" as used herein may include mixtures of different silanes and/or silane derivative compounds.

In some examples, the silane or silane derivative includes an unsaturated moiety capable of reacting with a functional group of the functionalized polymer layer. As used herein, the term "unsaturated moiety" refers to a chemical group that includes an alkene, alkyne, cycloalkene, cycloalkyne, heterocyclic alkene, heterocyclic alkyne, or optionally substituted variants thereof (including at least one double bond or one triple bond). The unsaturated moiety may be monovalent or divalent. When the unsaturated moiety is monovalent, cycloalkene, cycloalkyne, heterocycloalkene, and heterocycloalkyne are used interchangeably with cycloalkenyl, cycloalkynyl, heterocycloalkenyl, and heterocycloalkynyl, respectively. When the unsaturated moiety is divalent, cycloalkene, cycloalkyne, heterocyclic alkene, and heterocyclic alkyne are used interchangeably with cycloalkenylene, cycloalkynylene, heterocycloalkenylene, and heterocycloalkynylene, respectively.

The unsaturated moiety may be covalently attached directly to the silicon atom of the silane or silane derivative, or indirectly attached through a linker. Examples of suitable linkers include optionally substituted alkylenes (e.g., divalent saturated aliphatic groups (such as ethylene) believed to be derived from olefins by opening a double bond or from alkanes by removing two hydrogen atoms from different carbon atoms), substituted polyethylene glycols, and the like.

As used herein, a "spacer layer" refers to a material that bonds two components together. In some examples, the spacer layer may be, or may be in contact with, a radiation absorbing material that facilitates bonding.

As used herein, the term "surface chemistry" refers to a chemically and/or biologically active component incorporated into the recesses of a patterned substrate. Examples of surface chemistries disclosed herein include functionalized polymer layers attached to at least a portion of the substrate surface and/or primers attached to at least a portion of the functionalized polymer layers.

The "thiol" functional group refers to-SH.

As used herein, the terms "tetrazine" and "tetrazinyl" refer to six-membered heteroaryl groups containing four nitrogen atoms. The tetrazine may be optionally substituted.

As used herein, "tetrazole" refers to a five-membered heterocyclic group that includes four nitrogen atoms. The tetrazole can be optionally substituted.

An example of a method 100 is depicted in fig. 1. The method 100 includes applying a functionalized coating in recesses of a patterned flow cell substrate, wherein the recesses are separated by interstitial regions (as indicated by reference numeral 102), grafting primers onto the functionalized coating to form a grafted functionalized coating in the recesses (as indicated by reference numeral 104), and applying a hydrogel over at least the grafted functionalized coating (as indicated by reference numeral 106).

The patterned flow cell substrate can be a patterned wafer or a patterned die or any of the other patterned substrates disclosed herein. Any of the examples of substrates described herein may be used. The patterned substrate (shown as reference numeral 12 in fig. 3A and 4) includes recesses defined on or in the exposed layer or substrate surface, and gap regions separating adjacent recesses. The depressions may be fabricated in or on the substrate using a variety of techniques, including, for example, photolithography, nanoimprint, stamping techniques, embossing techniques, molding techniques, microetching techniques, printing techniques, and the like. As will be appreciated by those skilled in the art, the technique used will depend on the composition and shape of the substrate. Many different recess layouts may be envisaged, as discussed below with reference to fig. 4A.

Although not shown in fig. 1, prior to applying the functionalized coating and grafting primers (i.e., prior to adding the surface chemistry), the method may include treating the surface by another process that exposes the patterned substrate to a cleaning process and/or prepares the patterned substrate surface (e.g., depressions, and in some cases, adjacent interstitial regions) for subsequent surface chemistry deposition. For example, the method can include treating the surface of the flow cell substrate to attach functional groups to the surface to form treated recesses, and in some cases, treated interstitial regions. More detailed examples of the treatment processes (e.g., cleaning processes and surface preparation processes) are discussed below with reference to fig. 3A-3I.

In the example shown in fig. 1, adding a surface chemistry includes applying a functionalized coating in the depression (reference numeral 102) and grafting a primer onto the functionalized coating (reference numeral 104).

Examples of functionalized coatings include acrylamide copolymers, such as poly (N- (5-azidoacetamidylpentyl) acrylamide-co-acrylamide), PAZAM. PAZAM and some other forms of acrylamide copolymers are represented by formula (I):

wherein:

R^Aselected from the group consisting of azido, optionally substituted amino, optionally substituted alkenyl, optionally substituted hydrazone, optionally substituted hydrazine, carboxyl, hydroxyl, optionally substituted tetrazole, optionally substituted tetrazine, nitrile oxide, nitrone, and thiol;

R^Bis hydrogen or optionally substituted alkyl;

R^C、R^Dand R^EIndependently selected from H and optionally substituted alkyl；

-(CH₂)_pEach of-may be optionally substituted;

p is an integer ranging from 1 to 50;

n is an integer ranging from 1 to 50,000; and

m is an integer ranging from 1 to 100,000.

One of ordinary skill in the art will recognize that the arrangement of repeating "n" and "m" features in formula (I) is representative, and that the monomeric subunits may be present in any order in the polymer structure (e.g., random, block, patterned, or combinations thereof).

One specific example of a PAZAM is represented by the formula:

wherein n is an integer ranging from 1 to 20,000, and m is an integer ranging from 1 to 100,000.

The molecular weight of PAZAM may range from about 10kDa to about 1500kDa, or in a particular example, may be about 312 kDa.

In some examples, the PAZAM is a linear polymer. In some other examples, the PAZAM is a lightly crosslinked polymer.

In other examples, the functionalized coating may be a modification of formula (I). In one example, the acrylamide units may be substituted with N, N-dimethylacrylamideAnd (4) replacing. In this example, the acrylamide unit in the formula (I) may beInstead, R^D、R^EAnd R^FEach is H, and R^GAnd R^HEach is a methyl group (different from H in the case of acrylamide). In this example, q may be an integer ranging from 1 to 10,000. In another example, in addition to acrylamide units, there may be providedN, N-dimethylacrylamide was used. In this example, formula (I) may also include(except for the repeated "n" and "m" features), wherein R^D、R^EAnd R^FEach is H, and R^GAnd R^HEach is a methyl group. In this example, q may be an integer ranging from 1 to 100,000.

It will be appreciated that other functionalized molecules may be used to form the functionalized coating, so long as they are functionalized to interact with the patterned substrate and subsequently applied primers. Other examples of suitable molecules for forming the functionalized coating include those having a colloidal structure, such as agarose; or a polymer network, such as gelatin; or crosslinked polymer structures such as polyacrylamide polymers and copolymers, Silane Free Acrylamide (SFA) or the azide form of SFA. Examples of suitable polyacrylamide polymers may be synthesized from acrylamide and acrylic acid or vinyl-containing acrylic acid, or from monomers that form a [2+2] cycloaddition reaction.

The functionalized molecules (e.g., PAZAM) can be deposited on the surface of the patterned substrate using spin coating, or dip coating, or the functionalized molecules are flowed under positive or negative pressure, or another suitable technique. The functionalizing molecules may be present in a mixture. In one example, the mixture includes PAZAM in water or in a mixture of ethanol and water.

After coating, the functionalizing molecules may also be exposed to a curing process to form a functionalized coating over the entire patterned substrate (i.e., over the recessed and void regions). In one example, the functionalizing molecule curing may be performed at a temperature in a temperature range of room temperature (e.g., about 25 ℃) to about 60 ℃ for a time period of about 5 minutes to about 2 hours.

To form a functionalized coating in the recesses of the patterned substrate and not on the interstitial regions, i) an alkaline aqueous slurry having a pH ranging from about 7.5 to about 11 and comprising abrasive particles; or ii) the polishing pad and the solution without abrasive particles polish the functionalized coating away from the interstitial regions.

In this example of the method 100, the primer is then grafted onto the functionalized coating remaining in the depression, as indicated by reference numeral 104, to form a grafted functionalized coating. Examples of suitable primers include forward amplification primers or reverse amplification primers. Specific examples of suitable primers include the P5 or P7 primers used on the surface of commercial flow cells sold by Illumina incMISEQ^TM、MISEQX^TM、NEXTSEQ^TM、NOVASEQ^TM、GENOME ANALYZER^TMAnd other instrument platforms.

Grafting can be accomplished by dip coating, spray coating, stirred dispense, or by another suitable method of attaching primers to the functionalized coating in at least some of the recesses. Each of these example techniques may utilize a primer solution or mixture, which may include primers, water, a buffer, and a catalyst.

Soaking the coating may include immersing the patterned substrate (with the functionalized coating in its recesses) in a series of temperature-controlled baths. The bath may also be flow controlled and/or blanketed with a nitrogen blanket. The bath may include a primer solution or mixture. In various baths, primers are attached to the functionalized coating in at least some of the recesses. In one example, the coated and polished patterned substrate is introduced into a first bath comprising a primer solution or mixture, where a reaction occurs to attach the primers, and then the patterned substrate is moved to a separate bath for washing. The patterned substrate may be moved between baths using a robotic arm or manually. The drying system may also be used in dip coating.

Spray coating can be accomplished by spraying the primer solution or mixture directly onto the coated and polished patterned substrate. The sprayed wafer may be incubated at a temperature in the range of about 0 ℃ to about 70 ℃ for a period of about 4 minutes to about 60 minutes. After incubation, the primer solution or mixture can be diluted and removed using, for example, a spin coater.

The stirring distribution can be carried out according to the pool and spin off method, and thus can be accomplished with a spin coater. The primer solution or mixture can be applied (manually or by an automated process) to the coated and polished patterned substrate. The applied primer solution or mixture may be applied to or spread over the entire surface of the coated and polished patterned substrate. The primer coated patterned substrate can be incubated at a temperature ranging from about 0 ℃ to about 80 ℃ for a period of time ranging from about 2 minutes to about 60 minutes. After incubation, the primer solution or mixture can be diluted and removed using, for example, a spin coater.

In one example, after the primer is grafted to the functionalized coating in the recess to form a grafted functionalized coating, this example of the method 100 further includes applying a hydrogel to the grafted functionalized coating (as shown at reference numeral 106).

The hydrogel may be any hydrophilic polymer exposed to the flow cell that serves as a sequencing template filter. The deposition of the hydrogel is controlled in part by the concentration of the polymer in the solution deposited on the flow cell. The hydrogel slows down the diffusion of a sequencing template into the recess, thus having a time that allows a single sequencing template to seed and cluster in the recess before another sequencing template can diffuse through the hydrogel. The hydrogel also remains on the flow cell during sequencing template seeding and during other sequencing steps, and is therefore not water soluble or removable in the liquid to which it is exposed during the sequencing process. Some examples of hydrogels include PAZAM (or variants thereof as described herein), cross-linked polyacrylamide, sepharose, cross-linked polyethylene glycol (PEG), and the like. The hydrogel may be other acrylamide-based copolymers, agarose-based copolymers, or PEG-based copolymers. It is understood that X-based copolymers (e.g., acrylamide-based, agarose-based, PEG-based, etc.) include X components in an amount of about 10% or more of the molecular weight composition. In some examples, the X-based copolymer comprises about 10% of the molecular weight composition, or about 11% of the molecular weight composition, or about 12% of the molecular weight composition, or about 15% of the molecular weight composition, or about 20% of the molecular weight composition, or about 39% of the molecular weight composition, or higher percentage of the X component. Furthermore, the X component may be higher or lower than the given percentage as long as the copolymer functions as a hydrogel. Crosslinked PEG hydrogels can be synthesized by covalent crosslinking of PEG macromers with reactive chain ends, such as acrylate, methacrylate, allyl ether, maleimide, vinyl sulfone, NHS ester, and vinyl ether groups. Any of the exemplary hydrogels may include hydrophobic or hydrophilic side chains.

The hydrogel is not grafted with a primer, but is coated with a primer.

In some examples, the hydrogel can be selectively deposited or patterned so as to cover the surface chemistry (in this example, the functionalized coating and primers thereon) and so that the bonding areas of the patterned flow cell substrate remain exposed. The bonding areas of the patterned flow cell substrate are typically located on some of the interstitial areas of the patterned flow cell substrate where the cover is bonded to the patterned substrate. When the patterned substrate is a wafer, the bonding regions may define the boundaries (e.g., perimeter) of several flow cells formed by the wafer. When the patterned substrate is a mold, the bonding region can define an outer boundary (e.g., perimeter) of one flow cell formed. It should be understood that other portions of the patterned flow cell substrate (which are not part of the bonded regions) may be covered by the hydrogel.

In this example of the method 100, selectively depositing or patterning the hydrogel can be accomplished by solution incubation, dip coating, spin coating, spray coating, ultrasonic spray coating, doctor blade coating, aerosol printing, or ink jet printing. A mask may be used to cover the bonding areas of the patterned substrate so that the hydrogel is not applied over the bonding areas. Selective deposition of the hydrogel can be used to deposit the hydrogel on the grafted functionalized coating in the recesses without depositing on the interstitial regions.

In other examples, the cover can be bonded to the bonding region of the patterned flow cell substrate after the functionalized coating is formed, and the primers and hydrogel can be applied using a flow through process.

Each of the various exemplary techniques for applying a hydrogel may utilize an aqueous mixture, which may include water and up to about 0.1% (mass to volume) of a hydrogel material. In some examples, the hydrogel material comprises 0.1% or less of the aqueous mixture. In other examples, the aqueous mixture comprises from about 0.001% to about 0.1% hydrogel material, or from about 0.025% to about 0.005% hydrogel material. It should be understood that the concentration of the aqueous mixture may vary depending on the flow cell configuration (e.g., the size of the flow channels, inlets and outlets, etc.). For example, when flow through deposition is utilized, the concentration may be selected such that the aqueous mixture may flow through the flow cell without clogging interfaces, flow channels, etc. Thus, the concentration may also be higher than about 0.1%. The hydrogel material (and resulting hydrogel coating) can be any of the examples disclosed herein (i.e., PAZAM or a variant thereof, cross-linked polyacrylamide, agarose gel, etc.).

In some examples, the aqueous mixture may also include additives such as co-solvents, antioxidants, dyes, ultraviolet light stabilizers, processing aids, and the like. These additives may be included in the aqueous mixture in amounts that do not adversely affect the flowability of the mixture or the film-forming ability of the hydrogel.

After application of the aqueous mixture, incubation is allowed to form a hydrogel. The time and temperature for incubation of the solution can be any time and temperature sufficient for hydrogel formation. For example, the temperature may range from room temperature to about 65 ℃, and the time may range from about 5 minutes to about 1 hour, or longer. In one example, the solution incubation is performed at a temperature of about 50 ℃ for about 10 minutes.

In some cases, the aqueous mixture may be partially dried during the hydrogel formation process. Partial drying may be accomplished by air exposure, nitrogen exposure, vacuum, heating (e.g., in an oven), or spin coating (i.e., spinning until dry). In examples where heating is used, the temperature may be about 50 ℃, and the hydrogel may be maintained at this temperature for about 10 minutes. The hydrogel can also be washed with a dilute buffer.

Another example of a method 200 is depicted in fig. 2. The method 200 includes attaching a silane or silane derivative to a surface of a patterned substrate comprising a flow channel having a recess defined therein, wherein the recess is separated by a gap region, thereby forming a silanized recess and a silanized gap region (reference numeral 202), applying a functionalized coating in the silanized recess and on the silanized gap region (reference numeral 204); polishing the functionalized coating from the silanized interstitial regions (reference numeral 206); grafting a primer onto the functionalized coating in the silanized depression to form a grafted functionalized coating in the depression (reference numeral 208); and applying a hydrogel (reference numeral 210) over the grafted functionalized coating in the depression. Examples of the method 200 will be further described in fig. 3A through 3D with reference to fig. 3A through 3E in conjunction with fig. 3H and 3I.

Fig. 3A is a cross-sectional view of an example of patterned substrate 12. Patterned substrate 12 may be a patterned wafer or a patterned die or any other patterned substrate (e.g., a panel, a rectangular sheet, etc.). Any of the examples of substrate 12 described herein may be used. The patterned wafer may be used to form several flow cells, and the patterned die may be used to form a single flow cell. In one example, the substrate may have a diameter in the range of about 2mm to about 300mm, or a rectangular sheet or panel having a maximum dimension of up to 10 feet (3 meters). In one example, the base wafer has a diameter in the range of about 200mm to about 300 mm. In another example, the base mold has a width in a range from about 0.1mm to about 10 mm. Although example dimensions have been provided, it should be understood that substrates having any suitable dimensions may be used.

The patterned substrate 12 includes recesses 14 defined on or in an exposed layer or surface of the substrate 12 and gap regions 16 separating adjacent recesses 14. In the examples disclosed herein, the depressions 14 are functionalized with surface chemistries (e.g., 20, 22), while the gap regions 16 may be used for adhesion but without primers (22 shown in fig. 3E-3G and 3I) present thereon.

The depressions 14 can be fabricated in or on the substrate using a variety of techniques including, for example, photolithography, nanoimprinting, stamping techniques, embossing techniques, molding techniques, microetching techniques, printing techniques, and the like. As will be appreciated by those skilled in the art, the technique used will depend on the composition and shape of the substrate 12.

Many different layouts of the recesses 14 are contemplated, including regular, repeating, and irregular patterns. In one example, the depressions 14 are arranged in a hexagonal grid to provide close packing and increased density. Other layouts may include, for example, rectilinear (i.e., rectangular) layouts, triangular layouts, and the like. In some examples, the layout or pattern may be an x-y format of rows and columns of depressions 14. In some other examples, the layout or pattern may be a repeating arrangement of recesses 14 and/or interstitial regions 16. In still other examples, the layout or pattern may be a random arrangement of the recesses 14 and/or interstitial regions 16. The pattern may include spots, pads, holes, pillars, stripes, swirls, lines, triangles, rectangles, circles, arcs, chequers, lattices, diagonals, arrows, squares, and/or cross-hatching.

The layout or pattern may be characterized with respect to the density of the recesses 14 (i.e., the number of recesses 14) in a defined area. For example, the depressions 14 may be at about 2 million/mm²The density of (a) exists. The density can be adjusted to different densities, including, for example, at least about 100/mm²About 1,000/mm²About 10 ten thousand/mm²About 100 ten thousand/mm²About 200 ten thousand/mm²About 500 ten thousand/mm²About 1000 ten thousand/mm²About 5000 ten thousand/mm²Or a greater density. Alternatively or additionally, the density may be adjusted to not more than about 5000 ten thousand per mm²About 1000 ten thousand/mm²About 500 ten thousand/mm²About 200 ten thousand/mm²About 100 ten thousand/mm²About 10 ten thousand/mm²About 1,000/mm²About 100/mm²Or smaller. It should be further understood that the density of the depressions 14 on the substrate 12 can be between one of the lower and one of the upper values selected from the ranges described above. For example, a high density array may be characterized as having depressions 14 separated by less than about 100nm, a medium density array may be characterized as having depressions 14 separated by about 400nm to about 1 μm, and a low density array may be characterized as having depressions 14 separated by greater than about 1 μm. Although example densities are provided, it should be understood thatSubstrates having any suitable density may be used.

The layout or pattern may also or alternatively be characterized in terms of an average pitch, i.e., a pitch from the center of a depression 14 to the center of an adjacent interstitial region 16 (center-to-center pitch). The pattern may be regular such that the coefficient of variation of the average pitch is small, or the pattern may be irregular, in which case the coefficient of variation may be relatively large. In either case, the average pitch can be, for example, at least about 10nm, about 0.1 μm, about 0.5 μm, about 1 μm, about 5 μm, about 10 μm, about 100 μm or greater. Alternatively or additionally, the average pitch may be, for example, up to about 100 μm, about 10 μm, about 5 μm, about 1 μm, about 0.5 μm, about 0.1 μm, or less. The average pitch of the particular pattern of sites 16 may be between one of the lower and one of the upper limits selected from the ranges described above. In one example, the depressions 14 have a pitch (center-to-center pitch) of about 1.5 μm. Although example average pitch values have been provided, it should be understood that other average pitch values may be used.

In the example shown in fig. 3A to 3I, the recesses 14 are holes 14', and thus the patterned substrate 12 includes an array of holes 14' on its surface. The pores 14' may be micropores or nanopores. The size of each aperture 14' may be characterized by its volume, aperture opening area, depth, and/or diameter.

Each aperture 14' may have any volume capable of confining a liquid. For example, a minimum or maximum volume can be selected to accommodate the expected flux (e.g., multiplicity), resolution, analyte composition, or analyte reactivity for the downstream use of the flow cell. For example, the volume may be at least about 1 x 10^-3μm³About 1X 10^-2μm³About 0.1 μm³About 1 μm³About 10 μm³About 100 μm³Or larger. Alternatively or additionally, the volume may be up to about 1 × 10⁴μm³About 1X 10³μm³About 100 μm³About 10 μm³About 1 μm³About 0.1 μm³Or smaller. It should be understood that the functionalized coating may fill all or a portion of the volume of the pores 14'. SheetThe volume of coating in the holes 14' may be greater than, less than, or between the values specified above.

The area on the surface occupied by each pore opening may be selected based on criteria similar to those set forth above for the pore volume. For example, the area of each aperture opening on the surface may be at least about 1 × 10^-3μm²About 1X 10^-2μm²About 0.1 μm²About 1 μm²About 10 μm²About 100 μm²Or larger. Alternatively or additionally, the area may be at most about 1 × 10³μm²About 100 μm²About 10 μm²About 1 μm²About 0.1 μm²About 1X 10^-2μm²Or smaller. The area occupied by each aperture opening may be greater than, less than, or between the values specified above.

The depth of each well 14' can be at least about 0.1 μm, about 1 μm, about 10 μm, about 100 μm or more. Alternatively or additionally, the depth may be up to about 1 × 10³μ m, about 100 μm, about 10 μm, about 1 μm, about 0.1 μm or less. The depth of each aperture 14' may be greater than, less than, or between the values specified above.

In some cases, the diameter of each pore 14' can be at least about 50nm, about 0.1 μm, about 0.5 μm, about 1 μm, about 10 μm, about 100 μm, or more. Alternatively or additionally, the diameter may be up to about 1 × 10³μ m, about 100 μm, about 10 μm, about 1 μm, about 0.5 μm, about 0.1 μm or less (e.g., about 50 nm). The diameter of each hole 14' may be greater than, less than, or between the values specified above.

The patterned substrate 12 may be exposed to a series of processes to add the surface chemistries 20, 22 in the recesses 14.

Although not shown, it is understood that patterned substrate 12 can be exposed to plasma ashing to clean and activate the surfaces. For example, the plasma ashing process can remove organic species and introduce surface hydroxyl groups. Other suitable cleaning processes may be used to clean substrate 12, depending in part on the type of substrate 12. For example, chemical cleaning may be performed using an oxidizing agent or caustic solution.

The patterned substrate (shown in fig. 3A) may then be exposed to a process (fig. 3C) for preparing the substrate 12 for deposition of the functionalized polymer to form the functionalized polymer layer 20. In one example, patterned substrate 12 may be exposed to silylation, which attaches silane or silane derivative 18 (fig. 3B) to the patterned wafer surface. The silylation introduces silane or silane derivative 18 over the entire surface, including in the recesses 14, 14' (e.g., on the bottom surface and along the sidewalls) and over the gap regions 16. In some aspects, the silane or silane derivative is selectively introduced only to the recesses of the patterned substrate or to the micro-locations (which are separate from each other) of the non-patterned substrate.

Any silane or silane derivative 18 may be used to accomplish the silanization. The choice of silane or silane derivative 18 may depend in part on the functionalizing molecule to be used to form the functionalized polymer layer 20 (shown in fig. 3C), as it may be desirable to form a covalent bond between the silane or silane derivative 18 and the functionalized polymer layer 20. The method used to attach the silane or silane derivative 18 to the substrate 12 may vary depending on the silane or silane derivative 18 to be used. Several examples are listed herein.

In one example, the silane or silane derivative 18 is (3-aminopropyl) triethoxysilane (APTES) or (3-aminopropyl) trimethoxysilane (APTMS) (i.e., X-R^B-Si(OR^C)₃) Wherein X is amino, R^BIs- (CH)₂)₃-, and R^CIs ethyl or methyl. In this example, the surface of substrate 12 may be pretreated with (3-aminopropyl) triethoxysilane (APTES) or (3-aminopropyl) trimethoxysilane (APTMS) to covalently attach silicon to one or more oxygen atoms on the surface (without intending to be limited by the mechanism, one, two, or three oxygen atoms may be bonded per silicon). The chemically treated surface is baked to form an amine-based monolayer. The amine group is subsequently reacted with sulfo-HSAB to form the azide derivative. Using 1J/cm at 21 DEG C²To 30J/cm²UV activation of energyActive nitrene species are produced that can readily undergo various insertion reactions using PAZAM (e.g., functionalized molecules). In some aspects, the silane or silane derivative is selectively applied to the recesses of the patterned substrate or to the micro-locations on the non-patterned substrate.

Other silanization methods may also be used. Examples of suitable silylation methods include vapor deposition, YES methods, spin-on coatings, or other deposition methods. Some examples of methods and materials that may be used to silanize substrate 12 are described herein, although it will be understood that other methods and materials may be used.

In an example using a YES CVD furnace, patterned substrate 12 is placed in a CVD furnace. The chamber may be vented and the silylation cycle may then be initiated. During the recycling process, the silane or silane derivative container can be maintained at a suitable temperature (e.g., about 120 ℃ for norbornene silane), the silane or silane derivative vapor line can be maintained at a suitable temperature (e.g., about 125 ℃ for norbornene silane), and the vacuum line can be maintained at a suitable temperature (e.g., about 145 ℃).

In another example, silane or silane derivative 18 (e.g., liquid norbornene silane) may be deposited inside a glass vial and placed in a glass vacuum dryer with patterned substrate 12. The dryer may then be evacuated to a pressure in the range of about 15mTorr to about 30mTorr and placed inside the furnace at a temperature in the range of about 60 ℃ to about 125 ℃. The silanization was allowed to proceed and the dryer was subsequently removed from the oven, cooled and aerated in air.

Vapor deposition, YES methods, and/or vacuum dryers may be used with various silanes or silane derivatives 18, such as those silanes or silane derivatives 18 that include examples of the unsaturated moieties disclosed herein. These methods may be used, for example, when the silane or silane derivative 18 includes olefinic or cyclic olefinic unsaturation (such as norbornene, norbornene derivatives (e.g., (hetero) norbornene, including oxygen or nitrogen replacing one of the carbon atoms), trans-cyclooctene derivatives, trans-cyclopentene, trans-cycloheptene, trans-cyclononene, bicyclo [3.3.1] non-1-ene, bicyclo [4.3.1] dec-1 (9) -ene, bicyclo [4.2.1] non-1 (8) -ene, and bicyclo [4.2.1] non-1-ene). Any of these cycloalkenes may be substituted with, for example, an R group such as hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, cycloalkynyl, aryl, heteroaryl, heteroalicyclic, aralkyl, or (heteroalicyclic) alkyl. Examples of norbornene derivatives include [ (5-bicyclo [2.2.1] hept-2-enyl) ethyl ] trimethoxysilane. As other examples, these methods may be used when the silane or silane derivative 18 includes an alkyne or cycloalkyne unsaturated moiety, such as cyclooctyne, a cyclooctyne derivative, or bicyclononylene (e.g., bicyclo [6.1.0] non-4-yne or derivatives thereof, bicyclo [6.1.0] non-2-yne, or bicyclo [6.1.0] non-3-yne). These cycloalkynes may be substituted with any of the R groups described herein.

As shown in fig. 3B, the attachment of the silane or silane derivative 18 forms a silanized patterned substrate, including silanized recesses and silanized gap regions (which are one example of processed recesses and processed gap regions).

The silanized patterned wafer may then be exposed to a process that forms a functionalized polymer layer 20 on the silanized recesses and the silanized gap regions.

As described herein, examples of the functionalized polymer layer 20 include PAZAM, or any other molecule functionalized to interact with the patterned substrate 12 and the subsequently applied primers 22. The functionalizing molecules may be present in a mixture. In one example, the mixture comprises PAZAM in water or an ethanol and water mixture. The functionalized polymer layer 20 may be formed on the surface of the silanized patterned wafer (e.g., on the silanized recesses and silanized gap regions) using any suitable technique. The functionalizing molecules may be deposited on the surface of patterned substrate 12 using spin coating, or dip coating, or flowing of the functionalizing molecules under positive or negative pressure, or other suitable techniques. The resulting layer 20 is shown in fig. 3C.

The functionalized polymer layer 20 may be attached to the silanized depression and the silanized interstitial region (i.e., 18) by covalent bonding. The covalent attachment of the functionalized polymer layer 20 to the silanized depression is helpful to maintain the functionalized polymer layer 20 in the depression 14, 14' throughout the life of the finally-formed flow cell during various uses. The following are some examples of reactions that may occur between the silane or silane derivative 18 and the functionalized polymer layer 20.

When the silane or silane derivative 18 includes norbornene or norbornene derivative as the unsaturated moiety, the norbornene or norbornene derivative may: i) 1, 3-dipolar cycloaddition with the azide/azide group of PAZAM; ii) a coupling reaction with a tetrazine group attached to PAZAM; iii) cycloaddition with a hydrazone group attached to PAZAM; iv) a photo-click reaction (photo-click reaction) with the tetrazolyl group attached to the PAZAM; or v) cycloaddition to a nitrile oxide group attached to PAZAM.

When silane or silane derivative 18 includes cyclooctyne or a cyclooctyne derivative as the unsaturated moiety, the cyclooctyne or cyclooctyne derivative may: i) (ii) an azide-alkyne 1, 3-cycloaddition (SPAAC) reaction promoted by strain with the azide/azide groups of PAZAM; or ii) a strain-promoted alkyne-nitrile oxide cycloaddition reaction with a nitrile oxide group attached to PAZAM.

When silane or silane derivative 18 includes bicyclononyl as the unsaturated moiety, the bicyclononyl may undergo a similar SPAAC alkyne cycloaddition with an azide or nitrile oxide attached to PAZAM due to strain in the bicyclic ring system.

Although not shown, it is understood that in some examples of the method, patterned substrate 12 may not be exposed to silylation. Rather, patterned substrate 12 can be exposed to plasma ashing, and functionalized polymer layer 20 can then be spin coated (or otherwise deposited) directly on plasma ashed patterned substrate 12. In this example, plasma ashing can generate surfactants (e.g., -OH groups) that can adhere the functionalized coating 20 to the patterned substrate 12. In these examples, the functionalized polymer layer 20 is selected to be reactive with surface groups generated by plasma ashing.

After coating, the functionalizing molecules may also be exposed to a curing process to form a functionalized polymer layer 20 over the entire patterned substrate (i.e., over the recesses 14 and interstitial regions 16). In one example, the functionalizing molecule curing may be performed at a temperature ranging from room temperature (e.g., about 25 ℃) to about 95 ℃ for a time period ranging from about 1 millisecond to about several days. In another example, the time may range from 10 seconds to at least 24 hours. In yet another example, the time period may range from about 5 minutes to about 2 hours.

The silanized and coated patterned substrate (shown in fig. 3C) may be exposed to a cleaning process. The treatment may utilize a water bath and ultrasound. The water bath may be maintained at a relatively low temperature in the range of about 22 ℃ to about 45 ℃. In another example, the water bath temperature ranges from about 25 ℃ to about 30 ℃.

The silanized and coated patterned substrate is then exposed to polishing to remove portions of the functionalized polymer layer 20 from the silanized interstitial regions, if desired. The silanized, coated and polished substrates are shown in fig. 3D. The portion of the silane or silane derivative adjacent to the gap region 16 may or may not be removed as a result of polishing. Thus, in fig. 3D to 3I, the portions of the silane or silane derivative 18 adjacent to the gap region 16 are shown in phantom because they may at least partially remain after polishing or may be removed after polishing. When these silanized portions are completely removed, it is understood that the underlying substrate 12 is exposed.

The polishing process can be carried out with mild chemical slurries (including, for example, abrasives, buffers, chelating agents, surfactants, and/or dispersants) that can remove the thin functionalized polymer layer 20, and in some cases, at least a portion of the silane or silane derivative 18, from the interstitial regions 16 without deleteriously affecting the underlying substrate 12 in those regions. Alternatively, polishing may be performed with a solution that does not include abrasive particles.

The chemical slurry may be used in a chemical mechanical polishing system to polish the surface of the silanized and coated patterned substrate shown in fig. 3C. A polishing head/pad or other polishing tool is capable of polishing the functionalized polymer layer 20 from the gap region 16 while retaining the functionalized polymer layer 20 in the recesses 14, 14' and maintaining the underlying substrate 12 at least substantially intact. As an example, the polishing head may be a Strasbaugh ViPRR II polishing head.

As described above, polishing can be performed with a polishing pad and a solution without any abrasives. For example, the polishing pad can be used with a solution that does not contain abrasive particles (i.e., a solution that does not include abrasive particles).

The polishing removes portions of the functionalized polymer layer 20 (and in some cases, at least portions of the silane or silane derivative 18) from the interstitial regions 16 and leaves portions of the functionalized polymer layer 20 in the silanized recesses, as shown in fig. 3D. Also as described above, the gap region 16 may remain silanized after polishing is complete. In other words, the silanized interstitial regions may remain intact after polishing. Alternatively (as shown in phantom in 18), the silane or silane derivative 18 may be removed from the gap region 16 as a result of the polishing.

Although not shown, it is understood that the silanized, coated, and polished patterned substrate (as shown in fig. 3D) can be exposed to a cleaning process. The treatment may utilize a water bath and ultrasound. The water bath may be maintained at a relatively low temperature in the range of about 22 ℃ to about 30 ℃. The silanized, coated and polished patterned substrate may also be spin dried, or dried by other suitable techniques.

The silanized, coated and polished patterned substrate shown in fig. 3D may then be exposed to the treatment shown in fig. 3E to 3G, which results in flow cell 10, or to the treatment shown in fig. 3H to 3I, which results in flow cell 10'. In fig. 3E through 3G, the primers 22 are grafted and the hydrogel 24 is applied prior to bonding the lid 26 to the patterned flow cell substrate 12. As shown in fig. 3H and 3I, a cover 26 is bonded to the patterned flow cell base 12 prior to grafting the substrate 22 and applying the hydrogel 24.

In FIG. 3E, a grafting treatment is performed to graft the primer 22 to the functionalized polymer layer 20 in the recess 14, 14'. In this example, grafting can be accomplished by dip coating, spray coating, stirred dispensing, or by another suitable method of attaching the primers 22 to the functionalized polymer layer 20 in at least some of the recesses 14, 14'. Each of these example techniques may utilize a primer solution or mixture (which may include primers, water, buffer, and catalyst) disclosed herein, and proceed as described herein.

As shown in fig. 3F, after grafting the primers 22 onto the functionalized coating 20 in the recesses 14, 14', a hydrogel 24 is formed over the grafted functionalized coatings 20, 22 and over at least a portion of the patterned flow cell substrate 12. In this example, the hydrogel 24 may be formed on the exposed surface of the patterned substrate 12 in portions other than the bonded regions 25. In this example, the hydrogel 24 is selectively deposited or patterned on the interstitial regions 16 between adjacent depressions 14, 14', but not at the edges/periphery of the patterned substrate 12 where the bonded regions 25 are located. As described herein, selective deposition/patterning of the hydrogel 24 may be accomplished using an aqueous mixture. After the aqueous mixture is deposited, it may be partially dried to form hydrogel 24.

The cover 26 may then be bonded to the bonding area 25 as shown in fig. 3G. When patterned flow cell substrate 12 is a wafer, different regions of cover 26 may at least partially define respective flow channels 30 formed using the wafer. When patterned flow cell substrate 12 is a mold, lid 26 may define one or more flow channels 30 formed.

The cover 26 may be any material that is transparent to the excitation light directed to the surface chemistry 20, 22 in the recess 14. By way of example, the cover 26 may be glass (e.g., borosilicate, fused silica, etc.), plastic, or the like. Commercially available examples of suitable borosilicate glasses are available from Schott North America, incCommercially available examples of suitable plastic materials (i.e., cyclic olefin polymers) are available from Zeon Chemicals l.pProduct(s)。

In some examples, the cover 26 may be integrally formed with the sidewall 29 corresponding to the shape of the bonding area 25 and bonded to the bonding area 25. For example, a recess may be etched in the transparent block to form a substantially planar (e.g., top) portion 27 and sidewalls 29 extending from the substantially planar portion 27. The recesses may become flow channels 30 when the etched blocks are mounted to the bonding areas of the patterned substrate 12.

In other examples, the sidewall 29 and the cover 26 may be separate components coupled to one another. For example, the cover 26 may be a substantially rectangular block having an at least substantially planar outer surface and an at least substantially planar inner surface defining a portion (e.g., a top portion) of the flow channel 30 (once bonded with the patterned substrate 12). The block may be mounted to (e.g., bonded to) the sidewall 29, which is bonded to the bonding region 25 of the patterned flow cell substrate 12 and forms a sidewall of the flow channel 30. In this example, the sidewalls 29 can comprise any of the materials shown herein for the spacer layer (described below).

The lid 26 may be bonded to the bonding region 25 of the patterned flow cell substrate 12 using any suitable technique, such as laser bonding, diffusion bonding, anodic bonding, eutectic bonding, plasma activated bonding, glass frit bonding, or other methods known in the art. In one example, the spacer layer 28 may be used to bond the cover 26 to the bonding area 25. The spacer layer 28 may be any material that seals at least a portion of the gap region 16 (e.g., the bond region 25) of the patterned substrate 12 and the lid 26 together.

In one example, the spacer layer 28 may be a radiation absorbing material that absorbs radiation of wavelengths transmitted by the cover 26 and/or the patterned substrate 12. The absorbed energy in turn forms a bond between the spacer layer 28 and the cover 26 and between the spacer layer 28 and the patterned substrate 12. An example of such a radiation absorbing material is black from DuPont (USA)(polyimide with carbon black) which absorbs at about 1064 nm. It should be understood that polyimides may be usedWithout the addition of carbon black, except that the wavelength must be changed to a wavelength that is significantly absorbed by the natural polyimide material (e.g., 480 nm). As another example, polyimide CEN JP may bond when irradiated with 532nm light. When the spacer layer 28 is a radiation absorbing material, the spacer layer 28 may be located at the interface between the cover 26 and the patterned substrate 12 such that the spacer layer 28 contacts the desired bonding region 25. Compression (e.g., pressure of about 100 PSI) may be applied while laser energy of an appropriate wavelength is applied to the interface (i.e., irradiating the radiation absorbing material). Laser energy can be applied to the interface from the top and from the bottom to achieve a suitable bond.

In another example, the spacer layer 28 may include a radiation absorbing material in contact therewith. Radiation absorbing materials may be applied at the interface between spacer layer 28 and cover 26 and at the interface between spacer layer 28 and patterned flow cell substrate 12. By way of example, the spacer layer 28 may be polyimide and the separate radiation absorbing material may be carbon black. In this example, a separate radiation absorbing material absorbs the laser energy that forms the bond between the spacer layer 28 and the cover 26 and between the spacer layer 28 and the patterned substrate 12. In this example, compression may be applied at the respective interfaces while laser energy of an appropriate wavelength is applied to the interfaces (i.e., irradiating the radiation absorbing material).

When patterned flow substrate 12 is a wafer, spacer layer 28 and sidewall 29 (of cover 26 or connected to cover 26) may physically separate one flow channel 30 from an adjacent flow channel 30 and may be located at the periphery of the wafer. When patterned substrate 12 is a mold and the resulting flow cell 10 includes a single flow channel 30 or lane, spacer layer 28 and sidewall 29 (of cover 26 or attached to cover 26) may be located at the periphery of the mold to define flow channel 30 and seal flow cell 10. When patterned substrate 12 is a mold and the resulting flow cell 10 includes a plurality of separate flow channels 30 (e.g., eight or four flow channels/lanes), spacers 28 and sidewalls 29 (of cover 26 or of connecting cover 26) may physically separate one flow channel/lane 30 from an adjacent flow channel/lane 30 and may be located at the periphery of the mold. However, it should be understood that the spacer layer 28 and sidewalls 29 may be located in any desired area, depending on the embodiment.

When patterned substrate 12 is a mold, assembly of flow cell 10 may include bonding of lid 26. When the patterned substrate is a wafer, assembling the flow cell 10 may include other processing, such as dicing, after the cover 26 is bonded. In one example, the cover 26 may be bonded to the patterned wafer 12 and diced to form individual flow cells 10. As mentioned herein, the side walls 29 may physically separate one flow channel 30 from an adjacent flow channel 30 on the wafer, and thus dicing may be performed through at least some of the side walls 29, such that each individual flow cell 10 includes a desired number of flow channels 30, each having a portion of the original side wall 29 around its perimeter. In another example, the patterned wafer may be diced to form uncapped dies, which may have respective caps 26 bonded thereto to form individual flow cells 10.

In the example shown in fig. 3G, the lid 26 includes a top portion 27 integrally formed with a sidewall 29. The sidewalls 29 are bonded to the bonding regions 25 of the patterned substrate 12 by the spacers 28.

In summary, the lid 26 and the patterned flow cell substrate 12 define a flow channel 30 that is in selective fluid communication with the recess 14, 14'. The flow channels 30 may be used, for example, to selectively introduce reactive components or reactants to the hydrogel 24 and underlying surface chemistries 20, 22 to initiate a specified reaction in/at the recesses 14, 14'.

An example of flow cell 10 is shown in fig. 3G.

Referring now to fig. 3H and 3I, another example of the method 200 includes adhering a lid 26 to the patterned flow cell substrate 12 prior to grafting the primers 22 and applying the hydrogel 24.

As shown in fig. 3H, a functionalized coating (e.g., deposited and polished) has been applied as described in fig. 3D and with reference to fig. 1. At least some of the polished gap regions 16 can define bond regions 25, and a cover 26 can be bonded to the bond regions 25. The cover 26 may be any material and may have any of the configurations described herein. The cover 26 may be bonded to the bonding area 25 by any of the techniques described herein.

In the example shown in fig. 3H, the lid 26 includes a top portion 27 integrally formed with a sidewall 29. The sidewalls 29 are bonded to the bonding regions 25 of the patterned substrate 12 by spacers 28. After the cover 26 is bonded, a flow channel 30 is formed between the cover 26 and the patterned substrate 12. Flow channel 30 may be used to selectively introduce various fluids into flow cell 10' (fig. 3I).

In this example of the method 200, the primer 22 is then grafted onto the functionalized coating 20 in the recess 14, as shown in fig. 3I. Any of the primers described herein may be used. In this example, grafting can be accomplished by a flow-through process. In the flow-through method, a primer solution or mixture described herein can be introduced into the flow channel 30 through a corresponding inlet (not shown), can be maintained in the flow channel 30 for a sufficient time (i.e., incubation time) for the primers 22 to attach to the functionalized coating 20 in one or more recesses 14, and can then be removed from a corresponding outlet (not shown). After the primer 22 is attached, additional fluid may be directed through the flow channel 30 to wash the now functionalized recess and the flow channel 30.

After the primer 22 is grafted onto the functionalized coating 20 in the recesses 14, this example of the method 200 further includes forming a hydrogel on the grafted functionalized coating 20, 22 and on at least some of the interstitial regions 16 (e.g., those regions 16 between the recesses 14).

In this example, the hydrogel coating 14 may be deposited by a flow-through process. During flow-through, an aqueous mixture (comprising water and hydrogel material) may be introduced into the flow channel 30 of the flow cell through the respective inlets and may be maintained in the flow channel 30. Sufficient aqueous mixture may be introduced to cover the grafted functionalized coatings 20, 22 and any exposed surfaces of the patterned flow cell substrate 12 within the flow channel 30. This solution is incubated to form the hydrogel coating 24. In some examples, while the mixture is in the flow channel 30, the flow channel 30 may be exposed to a drying process, wherein air, nitrogen, or vacuum is flushed through the inlet for a set amount of time to dry the hydrogel coating 24 on the partial surface chemistries 20, 22 and any exposed portions of the substrate 12 (e.g., some of the interstitial regions 16). In this example, the hydrogel coating 24 can be any of the examples disclosed herein.

An example of a flow cell 10 "formed by the methods 100, 200 disclosed herein is shown in fig. 4. Flow cell 10 "includes a patterned substrate 12, which may be a mold that has been exposed to the process of methods 100, 200, or a wafer that has been exposed to the process of methods 100, 200 and diced.

Generally, patterned substrate 12 includes recesses 14 separated by interstitial regions 16 and surface chemistries 20, 22 located in the recesses 14. The surface chemistry includes a functionalized coating 20 and primers 22. Although not shown, it should be understood that the recesses 14 may also have a surface preparation or treatment chemistry (e.g., silane or silane derivative) located between the substrate 12 and the functionalized coating 20. This same surface preparation or treatment chemistry may also be located on the interstitial regions 16.

The flow cell 10 "also includes a cover 26 bonded to the bonded regions 25 of the patterned substrate 12, wherein the cover 26 at least partially defines flow channels 30A, 30B, etc. in selective communication with the recesses 14. In the example shown in fig. 4, the lid 26 includes a top portion 27 connected to a plurality of side walls 29, and these members 27, 29 define a portion of each of six flow channels 30A, 30B, 30C, 30D, 30E, 30F. A respective sidewall 29 separates one flow channel 30A, 30B, 30C, 30D, 30E, 30F from each adjacent flow channel 30A, 30B, 30C, 30D, 30E, 30F, each flow channel 30A, 30B, 30C, 30D, 30E, 30F being in selective fluid communication with a respective set of recesses 14.

Although not shown, the cover 26 or patterned substrate 12 can include inlets and outlets that are in fluid engagement with other ports (not shown) for directing fluids into the respective flow channels 30A, 30B, 30C, 30D, 30E, 30F (e.g., from a reagent cartridge or other fluid storage system) and out of the flow channels (e.g., to a waste abatement system).

The hydrogel/hydrogel coating 24 covers the surface chemistries 20, 22 in the depressions 14, as well as at least a portion of the patterned substrate 12 (e.g., those interstitial regions 16 that are also not bonded regions 25). In the example flow cell 10 ", the hydrogel/hydrogel coating 24 is formed as described herein. Thus, the hydrogel/hydrogel coating 24 may be any of the examples disclosed herein (i.e., PAZAM, cross-linked polyacrylamide, agarose gel, etc.).

Although not shown, it is understood that some examples of flow cells 10, 10', 10 "may be directly secured to, and thus in physical contact with, a detection device (not shown) by one or more securing mechanisms (e.g., adhesive, bonding, fasteners, etc.). The detection device may include a CMOS device (which includes a plurality of stacked layers including, for example, a silicon layer, a dielectric layer, a metal-dielectric layer, a metal layer, etc.) and an optical component. The optical components may be arranged such that the optical sensors of the detection device are at least substantially aligned with, and thus operatively associated with, the single optical waveguides of the detection device and the surface chemistries 20, 22 within the single recess 14, 14' or within the flow channel 30 of the flow cell.

Also, although not shown, it is understood that the functionalized substrate (having the surface chemistries 20, 22 and the hydrogel/hydrogel coating 24 thereon) may be bonded to another functionalized substrate having the surface chemistries 20, 22 and the hydrogel/hydrogel coating 24 thereon, as opposed to being bonded to the cover 26. The two functionalized surfaces may face each other and may have a flow channel defined therebetween. A spacer layer and suitable bonding methods may be used to bond the two functionalized substrates together.

The flow cells 10, 10', 10 "disclosed herein may be used in a variety of sequencing methods or techniques, including techniques commonly referred to as sequencing-by-synthesis (SBS), cycle array sequencing, ligation sequencing, pyrosequencing, and the like. With either of these techniques and in instances where a patterned substrate is used, amplification will be limited to the functionalized recesses since the functionalized polymer layer 20 and attached sequencing primers 22 are present in the functionalized recesses (i.e., recesses 14, 14' having surface chemistries 20, 22 thereon) and not on the gap regions 16. Furthermore, due to the presence of the hydrogel 24, there is more time (than when no hydrogel is included) to amplify one sequencing template into larger clusters, which increases the population of wells 14 seeded with a single sequencing template across the patterned flow cell substrate 12.

As an example, the compounds can be found in HISEQ such as that from Illumina, Inc. (San Diego, Calif.)^TM、HISEQX^TM、MISEQ^TM、NOVASEQ^TMOr NEXTSEQ^TMSequencing By Synthesis (SBS) reaction is performed on a sequencer system or the like. In SBS, extension of a nucleic acid primer (e.g., primer 22) along a nucleic acid template (i.e., sequencing template) is monitored to determine the nucleotide sequence in the template. The underlying chemical process may be polymerization (e.g., catalyzed by a polymerase) or ligation (e.g., catalyzed by a ligase). In certain polymerase-based SBS methods, fluorescently labeled nucleotides are added to the primer 22 (thereby extending the primer 22) in a template-dependent manner, such that detection of the order and type of nucleotides added to the primer 22 can be used to determine the sequence of the template. For example, to initiate the first SBS cycle, one or more labeled nucleotides, DNA polymerase, or the like can be delivered into or through the flow channel 30 or the like that houses the array of primers 22 coated with the hydrogel 24. Functionalized pits (i.e., pits 14, 14' having surface chemistries 20, 22 thereon) in which primer extension results in incorporation of labeled nucleotides can be detected by an imaging event. During an imaging event, an illumination system (not shown) may provide excitation light to the functionalized recesses (i.e., the recesses 14, 14' having the chemical surface species 20, 22 thereon).

In some examples, the nucleotide may further include a reversible termination property that terminates further primer extension once the nucleotide is added to primer 22. For example, a nucleotide analog having a reversible terminator moiety can be added to primer 22 such that subsequent extension cannot occur until a deblocking agent is delivered to remove the moiety. Thus, for examples using reversible termination, the deblocking agent may be delivered to the flow channel 30 or the like (before or after detection is performed).

Washing may be performed between each fluid delivery step. The SBS cycle can then be repeated n times to extend the primer 22 n nucleotides, thereby detecting sequences of length n.

Although SBS has been described in detail, it should be understood that the flow cells 10, 10', 10 "described herein may be used with other sequencing protocols, for typing or in other chemical and/or biological applications.

To further illustrate the invention, examples are given herein. It should be understood that these examples are provided for illustrative purposes and should not be construed as limiting the scope of the present disclosure.

Non-limiting working examples

Example 1

A flow cell comprising 8 flow channels/lanes defined on a patterned fused silica substrate was used, wherein each lane comprises 96 blocks (which correspond to the imaging area), and wherein each block is in fluid communication with a plurality of wells. A PAZAM layer was formed in each well and 1 μm primers were grafted on the PAZAM layer.

Lanes 1-4, and thus blocks 1 through 384, are comparative example lanes and blocks. Thus, in these lanes and blocks, the hydrogel layer was not applied on the PAZAM layer or primers.

Lanes 5-8, and thus block 385-768, are exemplary lanes and blocks. Thus, a hydrogel layer was applied over the PAZAM layer and primers in these lanes and blocks. The hydrogel coating is another layer of PAZAM applied by a flow-through method. A 0.025% solution of PAZAM in water was introduced into lanes 5-8 and heated to 60 ℃ and maintained at that temperature for about 10 minutes.

All lanes were washed with dilution buffer.

Sequencing cycles were performed in each of lanes 1-8. Phi X sequencing template solution with a concentration of 150pM was used.

Figure 5 shows the percentage of clusters that pass the filter (% pass filter (% PF)) and the percentage of wells occupied by DNA sequencing template (% occupied). The% pass filter (% PF) is a metric used to describe clusters that pass the purity threshold and is used for further processing and analysis of sequencing data. Higher% pass filters result in increased yield of unique clusters for sequencing data.

The data in fig. 5 show that% was increased by the filter (by about 5% to about 10%) when using hydrogel (compare data for blocks 1 to 384 (no hydrogel) to blocks 385 to 768 (with hydrogel)).

The difference between% occupancy and% passage through the filter is a rough estimate of the polyclonal cluster. The difference between the% occupancy and% PF blocks of the example blocks 385 to 768 is much less than the difference between the% occupancy and% PF blocks of the comparative blocks 1 to 384, indicating that PAZAM hydrogel coated blocks/lanes have much fewer polyclonal clusters than the comparative uncoated blocks/lanes.

Overall, the data in fig. 5 indicate that the presence of the hydrogel coating helps to improve the purity of the major components/clusters in the wells of the monoclonal and polyclonal clusters, which will also improve sequencing yield and data quality.

Example 2

Two flow cells were used, each comprising 8 flow channels/lanes defined on a patterned fused silica substrate, wherein each lane comprises 96 zones (and imaging regions), and wherein each zone is in fluid communication with a plurality of wells. A PAZAM layer was formed in each well, and 1 μm primers were grafted on the PAZAM layer.

In the comparative flow cell, no hydrogel coating was applied on the PAZAM layer or primers in any of the lanes and blocks.

In the example flow cell, a hydrogel coating was applied on the PAZAM layer and on the primers in each lane and block. The hydrogel coating is another layer of PAZAM applied by a flow-through method. The mixture/solution of PAZAM in water was introduced into lanes 1-8 of the example flow cell, heated to 60 ℃, and maintained at that temperature for about 10 minutes.

All lanes in the comparative flow cell and the example flow cell were washed with dilute buffer.

Sequencing cycles were performed in each of lanes 1-8 of each comparative flow cell and the example flow cell. In reading 1 in 151 cycle sequencing, and in reading 2 in another 151 cycle sequencing. Sequencing metrics were derived from the center of the block to eliminate edge effects. Different sequencing template solutions with different concentrations ranging from 100pM to 800pM were used in each lane. More specifically, lane 1 of each comparative and example flow cell was exposed to 100pM sequencing template solution; lane 2 of each comparative and example flow cell was exposed to 200pM sequencing template solution; lane 3 of each comparative and example flow cell was exposed to 300pM sequencing template solution; lane 4 of each comparative and example flow cell was exposed to 400pM sequencing template solution; lane 5 of each comparative and example flow cell was exposed to 500pM sequencing template solution; lane 6 of each comparative and example flow cell was exposed to 600pM sequencing template solution; lane 7 of each comparative and example flow cell was exposed to 700pM sequencing template solution; and lane 8 of each comparative and example flow cell was exposed to 800pM sequencing template solution.

Figure 6 shows the percentage of clusters that pass the filter (% pass filter (% PF)) for different lanes of the comparative and example flow cells. As shown, the% PF is more consistent over a wider concentration range for the example flow cell lane including the hydrogel than the comparative flow cell lane with the hydrogel.

Duplicate templates were bioinformatically removed from the example flow cell lane and the comparison flow cell lane depending on whether the reads were aligned to the exact same genomic position. The net% PF after repeated removal is shown in figure 7. Overall, using sequencing templates at concentrations ranging from 300pM to 800pM, higher yields (from about 2% to about 17% increase in yield) can be obtained using hydrogel-coated flow cells when compared to comparative flow cells.

For the comparative flow cell, the maximum% PF after repeated removal was 76.13% in lanes exposed to 300pM sequencing template solution. For the example flow cell, the maximum% PF after repeated removal was 83.42% in lanes exposed to 600pM sequencing template solution. This indicates a 9.6% increase in the monoclonal cluster.

Fig. 8A and 8B illustrate read 1 and read 2 mismatch rates (MMR) for the comparative and example flow cells after 150 sequencing cycles. Similar mismatches on the comparative and example flow cells indicate that the hydrogel coating did not adversely affect the sequencing operation.

Description of the other

It should be understood that all combinations of the foregoing concepts and other concepts discussed in greater detail below (provided that such concepts do not contradict each other) are considered to be part of the inventive subject matter disclosed herein. In particular, all combinations of claimed subject matter appearing at the end of this disclosure are considered part of the inventive subject matter disclosed herein. It is also to be understood that the terms explicitly employed herein, as may appear in any disclosure incorporated by reference, are to be accorded the most consistent meanings with the specific concepts disclosed herein.

Reference throughout the specification to "one example," "another example," "an example," and so forth, means that a particular element (e.g., feature, structure, and/or characteristic) described in connection with the example is included in at least one example described herein, and may or may not be present in other examples. In addition, it should be understood that in any instance, the elements used in any instance can be combined in any suitable manner, unless the context clearly dictates otherwise.

It should be understood that the ranges provided herein include the recited range as well as any value or subrange within the recited range. For example, a range of from 1 to 50,000 should be interpreted to include not only the explicitly recited limits of from 1 to 50,000, but also include individual values, such as about 708, about 945, about 3500, and the like, as well as sub-ranges, such as from about 825 to about 29,000, from about 95 to about 40,000, and the like. Further, when values are described using "about" and/or "substantially," they are intended to include minor variations (up to +/-10%) from the stated value.

Although a few examples have been described in detail, it should be understood that the disclosed examples may be modified. Accordingly, the foregoing description should be considered as non-limiting.

Claims (14)

1. A flow cell comprising

Comprising recesses separated by gap regions; and a patterned substrate comprising bonded regions;

a sequencing surface chemistry attached to each of the recesses, the sequencing surface chemistry comprising:

a functionalized coating; and

a primer grafted to the functionalized coating;

a non-grafted hydrogel selected from the group consisting of crosslinked polyacrylamide, sepharose, and crosslinked polyethylene glycol;

a cover attached to the patterned substrate at a bonding region; and

a flow channel defined between the patterned substrate and the lid.

2. The flow cell defined in claim 1 wherein the non-grafted hydrogel is also on at least some of the interstitial regions.

3. The flow cell defined in claim 1 wherein the functionalized coating is poly (N- (5-azidoacetamidylpentyl) acrylamide-co-acrylamide).

4. A method of making a flow cell, comprising:

applying a functionalized coating in recesses of a patterned flow cell substrate, wherein the recesses are separated by interstitial regions; and wherein the patterned flow cell substrate comprises bonded regions;

grafting a primer to the functionalized coating to form a grafted functionalized coating in the depression;

applying a non-grafted hydrogel over at least the grafted functionalized coating;

the non-grafted hydrogel is selected from cross-linked polyacrylamide, agarose gel and cross-linked polyethylene glycol; and

bonding a cover to the patterned substrate at a bonding region, thereby defining a flow channel between the flow cell substrate and the cover.

5. The method defined in claim 4, wherein the non-grafted hydrogel is disposed on the grafted functionalized coating and on some of the interstitial regions.

6. The method defined in claim 4 wherein prior to applying the functionalized coating, the method further comprises treating the surface of the patterned flow cell substrate to attach functional groups to the surface to form treated recesses and treated interstitial regions.

7. The method defined in claim 6 wherein applying the functionalized coating in the depressions comprises:

applying the functionalized coating in the treated recesses and on the treated interstitial regions; and

polishing the functionalized coating from the treated interstitial regions.

8. A method as defined in claim 4, wherein applying the non-grafted hydrogel comprises applying an aqueous mixture comprising from 0.001% up to 0.1% by mass of the hydrogel material.

9. The method defined in claim 4 wherein the bonded regions of the patterned flow cell substrate have a spacer layer bonded thereto, and wherein bonding a lid to the patterned flow cell substrate after the non-grafted hydrogel is applied comprises bonding the lid to the spacer layer.

10. The method defined in claim 4, wherein applying the hydrogel comprises selectively depositing the hydrogel on the grafted functionalized coating.

11. A method of making a flow cell comprising:

attaching a silane or silane derivative to a surface of a patterned substrate, the patterned substrate comprising a flow channel having defined recesses therein, wherein the recesses are separated by a gap region, thereby forming silanized recesses and silanized gap regions; and wherein the patterned flow cell substrate comprises bonded regions;

applying a functionalized coating in the silanized depressions and on the silanized gap regions;

polishing the functionalized coating from the silanized interstitial regions;

grafting a primer onto the functionalized coating in the silanized depression to form a grafted functionalized coating in the depression;

applying a non-grafted hydrogel over the grafted functionalized coating in the depression; the non-grafted hydrogel is selected from cross-linked polyacrylamide, agarose gel and cross-linked polyethylene glycol; and

bonding a cover to the patterned substrate at a bonding region, thereby defining a flow channel between the flow cell substrate and the cover.

12. The method as defined in claim 11, wherein applying said non-grafted hydrogel comprises applying an aqueous mixture comprising 0.001% up to 0.1% by mass by volume of a hydrogel material.

13. The method as defined in claim 11 wherein after polishing the functionalized coating and before grafting the primers, the method further comprises bonding a cover to at least some of the interstitial regions.

14. The method defined in claim 11, wherein applying the non-grafted hydrogel comprises selectively depositing the non-grafted hydrogel over the grafted functionalized coating in the depressions.