Patent Publication Number: US-2021170356-A1

Title: Functionalized surfaces and preparation thereof

Description:
CROSS-REFERENCE 
     This application is a Continuation of U.S. patent application Ser. No. 16/384,678, filed on Apr. 15, 2019, which is a Continuation of U.S. patent application Ser. No. 15/860,445, filed Jan. 2, 2018, now U.S. Pat. No. 10,384,189, issued on Aug. 20, 2019, which is a Continuation of U.S. patent application Ser. No. 15/365,826, filed on Nov. 30, 2016, now U.S. Pat. No. 9,895,673, issued Feb. 20, 2018, which claims the benefit of U.S. Provisional Application No. 62/261,753 filed on Dec. 1, 2015, which is incorporated herein by reference in their entirety. 
    
    
     BACKGROUND 
     The increasing miniaturization of biotechnology devices requires an increased resolution for deposition of materials on such devices. A variety of known techniques allow for medium to high resolution patterning on surfaces. However, such techniques present disadvantages such as material incompatibility or contamination. 
     BRIEF SUMMARY 
     Provided herein are methods for surface patterning, the methods comprising: applying a first set of molecules to a surface of a structure, wherein each of the first set of molecules binds to the surface and lacks a reactive group capable of binding to a nucleoside; applying electromagnetic radiation (EMR) to predetermined regions of the surface, wherein the EMR comprises a wavelength from about 100 nm to about 300 nm, wherein application of the EMR results in removal of the first set of molecules at the predetermined regions, thereby defining different loci for oligonucleic acid extension; and synthesizing a plurality of oligonucleic acids, wherein each oligonucleic acid extends from a different locus, and wherein the different loci are at least about 75% uniform when measured by calculating amplitude of signal variation for oligonucleic acids extending from each locus divided by total signal intensity following white light illumination using an optical microscope. Further provided are methods wherein greater than about 90% of the first set of molecules are removed at the predetermined regions of the surface following application of EMR. Further provided are methods wherein about 100% of the first set of molecules are removed at the predetermined regions of the surface following application of EMR. Further provided are methods wherein the predetermined regions have a width of about 1 to about 500 um. Further provided are methods wherein the predetermined regions have a width of about 1 to about 100 um. Further provided are methods wherein the predetermined regions have a width of about 3 um to about 60 um. Further provided are methods wherein the predetermined regions have a width of at least 3 um. Further provided are methods wherein the predetermined regions have a perimeter that is a circle or a rectangle in shape. Further provided are methods wherein the first set of molecules comprises a fluorosilane. Further provided are methods wherein the first set of molecules comprises perfluorooctyltrichlorosilane, (tridecafluoro-1,1,2,2-tetrahydrooctyl)trichlorosilane, or tridecafluoro-1,1,2,2-tetrahydrooctyl)trimethoxysilane. Further provided are methods further comprising applying a second set of molecules to the surface after application of the EMR, wherein each of the second set of molecules binds to the predetermined regions of the surface and comprises the reactive group capable of binding to a nucleoside. Further provided are methods wherein the second set of molecules comprises an aminosilane. Further provided are methods wherein the second set of molecules comprises N-(3-triethoxysilylpropyl)-4-hydroxybutyramide (HAPS), 11-acetoxyundecyltriethoxysilane, n-decyltriethoxysilane, (3-aminopropyl)trimethoxysilane, (3-aminopropyl)triethoxysilane, 3-glycidoxypropyltrimethoxysilane (GOP S), or 3-iodo-propyltrimethoxysilane. Further provided are methods wherein each of the oligonucleic acids comprises about 25 bases to about 2 kb in length. Further provided are methods wherein each of the oligonucleic acids comprises about 25 bases to about 150 bases in length. Further provided are methods wherein the oligonucleic acids extending from each locus are about 80% uniform when measured by calculating amplitude of signal variation for oligonucleic acids extending from each locus divided by total signal intensity following white light illumination using an optical microscope. Further provided are methods wherein the oligonucleic acids extending from the different loci collectively encode sequence for a preselected gene. Further provided are methods wherein the EMR comprises a wavelength from about 150 to about 200 nm. Further provided are methods wherein the EMR has a wavelength of about 172 nm. Further provided are methods wherein the surface is substantially planar. Further provided are methods wherein the surface comprises microstructures. Further provided are methods wherein the microstructures comprise channels or wells. Further provided are methods wherein the EMR is emitted from a lamp or a laser. Further provided are methods wherein the lamp comprises an emission source in the shape of a cylinder or a flat panel. Further provided are methods wherein the flat panel has a surface area that is at least 36 inches squared. Further provided are methods wherein the structure is a plate, tape, or belt. 
     Provided herein are methods for surface patterning, the methods comprising: applying a first set of molecules to a surface of a structure, wherein each of the first set of molecules comprises a reactive group capable of binding to a nucleoside; applying electromagnetic radiation (EMR) to predetermined regions of the surface, wherein the EMR comprises a wavelength from about 100 nm to about 300 nm, wherein application of the EMR results in removal of the first set of molecules at the predetermined regions, thereby defining different loci for oligonucleic acid extension; and synthesizing a plurality of oligonucleic acids, wherein each oligonucleic acid extends from a different locus, and wherein the different loci are at least about 75% uniform when measured by calculating amplitude of signal variation for oligonucleic acids extending from each locus divided by total signal intensity following white light illumination using an optical microscope. Further provided are methods wherein greater than about 90% of the first set of molecules are removed at the predetermined regions of the surface following application of EMR. Further provided are methods wherein about 100% of the first set of molecules are removed at the predetermined regions of the surface following application of EMR. Further provided are methods wherein the predetermined regions have a width of about 1 to about 500 um. Further provided are methods wherein the predetermined regions have a width of about 1 to about 100 um. Further provided are methods wherein the predetermined regions have a width of about 3 um to about 60 um. Further provided are methods wherein the predetermined regions have a width of at least 3 um. Further provided are methods wherein the predetermined regions have a perimeter that is a circle or a rectangle in shape. Further provided are methods wherein the structure is a plate, tape, or belt. Further provided are methods wherein the first set of molecules comprises an aminosilane. Further provided are methods wherein the first set of molecules comprises N-(3-triethoxysilylpropyl)-4-hydroxybutyramide (HAPS), 11-acetoxyundecyltriethoxysilane, n-decyltriethoxysilane, (3-aminopropyl)trimethoxysilane, (3-aminopropyl)triethoxysilane, 3-glycidoxypropyltrimethoxysilane (GOPS), or 3-iodo-propyltrimethoxysilane. Further provided are methods further comprising applying a second set of molecules to the surface after application of the EMR, wherein each of the second set of molecules binds to the predetermined regions of the surface and lacks the reactive group capable of binding to a nucleoside. Further provided are methods wherein the second set of molecules comprises a fluorosilane. Further provided are methods wherein the second set of molecules comprises perfluorooctyltrichlorosilane, octylchlorosilane, octadecyltrichlorosilane, (tridecafluoro-1,1,2,2-tetrahydrooctyl)trichlorosilane, or tridecafluoro-1,1,2,2-tetrahydrooctyl)trimethoxysilane. Further provided are methods wherein each of the oligonucleic acids comprises about 25 bases to about 2 kb in length. Further provided are methods wherein each of the oligonucleic acids comprises about 25 bases to about 150 bases in length. Further provided are methods wherein each locus comprises a population of oligonucleic acids about 80% uniform when measured by calculating amplitude of signal variation for oligonucleic acids extending from each locus divided by total signal intensity following white light illumination using an optical microscope. Further provided are methods wherein the oligonucleic acids extending from the different loci collectively encode sequence for a preselected gene. Further provided are methods wherein the EMR comprises a wavelength from about 150 to about 200 nm. Further provided are methods wherein the EMR has a wavelength of about 172 nm. Further provided are methods wherein the surface is substantially planar. Further provided are methods wherein the microstructures comprise channels or wells. 
     Provided herein are methods for surface patterning, the methods comprising: applying a first set of molecules to a surface of a structure, wherein each of the first set of molecules binds to the surface and comprises a reactive group capable of binding to a nucleoside; synthesizing a first layer of oligonucleic acids, wherein each oligonucleic acid in the first layer of oligonucleic acids comprises about 10 to about 100 bases in length and extends from the surface; applying electromagnetic radiation (EMR) to a predetermined region of the surface to selectively remove a portion of the layer of oligonucleic acids, wherein the EMR comprises a wavelength from about 100 nm to about 300 nm; and synthesizing a second layer of oligonucleic acids, wherein each oligonucleic acid in the second layer of oligonucleic extends acids from the remaining portion of the first layer of layer of oligonucleic acids. Further provided are methods wherein the first set of molecules comprises an aminosilane. Further provided are methods wherein the first set of molecules comprises N-(3-triethoxysilylpropyl)-4-hydroxybutyramide (HAPS), 11-acetoxyundecyltriethoxysilane, n-decyltriethoxysilane, (3-aminopropyl)trimethoxysilane, (3-aminopropyl)triethoxysilane, 3-glycidoxypropyltrimethoxysilane (GOPS), or 3-iodo-propyltrimethoxysilane. Further provided are methods further comprising applying a second set of molecules to the surface after application of the EMR, wherein each of the second set of molecules binds to the predetermined region of the surface and lacks the reactive group capable of binding to a nucleoside. Further provided are methods wherein the second set of molecules comprises a fluorosilane. Further provided are methods wherein the second set of molecules comprises perfluorooctyltrichlorosilane octylchlorosilane, octadecyltrichlorosilane, (tridecafluoro-1,1,2,2-tetrahydrooctyl)trichlorosilane, or tridecafluoro-1,1,2,2-tetrahydrooctyl)trimethoxysilane. Further provided are methods wherein the second layer of oligonucleic acids comprises about 25 bases to about 2 kb in length. Further provided are methods wherein the second layer of oligonucleic acids comprises about 25 bases to about 500 bases in length. Further provided are methods wherein the first layer of oligonucleic acids comprises a homopolymeric nucleic acid sequence. Further provided are methods wherein the homopolymeric nucleic acid sequence is about 50 bases in length. Further provided are methods wherein the EMR comprises a wavelength from about 150 to about 200 nm. Further provided are methods wherein the EMR comprises wavelength of about 172 nm. Further provided are methods wherein the EMR is emitted from a lamp or a laser. Further provided are methods wherein the lamp comprises an emission source in the shape of a cylinder or a flat panel. Further provided are methods wherein the flat panel has a surface area that is at least 36 inches squared. Further provided are methods wherein the structure is a plate, tape, or belt. Further provided are methods wherein the surface comprises a plurality of loci for oligonucleic acid extension, and wherein the loci are at least about 75% uniform when measured by calculating amplitude of signal variation for oligonucleic acids extending from each locus divided by total signal intensity following white light illumination using an optical microscope. Further provided are methods wherein the surface is substantially planar. Further provided are methods wherein the surface comprises microstructures. Further provided are methods wherein the microstructures comprise channels or wells. Further provided are methods further comprising releasing the plurality of oligonucleic acids and assembling a plurality of genes. 
     Provided herein is a library of synthesized oligonucleic acids, comprising a plurality of different oligonucleic acids, each different oligonucleic acid extending from a structure at a different loci, wherein the different loci are at least about 75% uniform when measured by calculating amplitude of signal variation for oligonucleic acids extending from each locus divided by total signal intensity following white light illumination using an optical microscope. Further provided is a library wherein the plurality of different oligonucleic acids comprises at least 20,000 different oligonucleic acids. Further provided is a library wherein the oligonucleic acids extending from each locus are about 80% uniform when measured by calculating amplitude of signal variation for oligonucleic acids extending from each locus divided by total signal intensity following white light illumination using an optical microscope. 
     Provided herein is are methods for gene synthesis, comprising providing predetermined sequences for a plurality of oligonucleic acids, wherein the plurality of oligonucleic acids collectively encode for a plurality of genes; providing a surface for oligonucleic acid synthesis; synthesizing the plurality of oligonucleic acids from the surface, wherein each oligonucleic acid extends from a different locus, and wherein the different loci are at least about 75% uniform when measured by calculating amplitude of signal variation for oligonucleic acids extending from each locus divided by total signal intensity following white light illumination using an optical microscope; and assembling the plurality of genes from the plurality of oligonucleic acids. Further provided herein are methods further comprising, prior to synthesizing: providing the surface for oligonucleic acid synthesis, wherein the surface comprises a first set of molecules, wherein each of the first set of molecules lacks a reactive group capable of binding to a nucleoside; applying electromagnetic radiation (EMR) to predetermined regions of the surface, wherein the EMR comprises a wavelength from about 100 nm to about 300 nm, wherein application of the EMR results in removal of the first set of molecules at the predetermined regions, thereby defining loci for oligonucleic acid extension. Provided herein are methods for gene synthesis, the methods comprising: providing predetermined sequences for a plurality of oligonucleic acids, wherein the plurality of oligonucleic acids collectively encode for a plurality of genes; providing a surface for oligonucleic acid synthesis, wherein the surface comprises a first set of molecules, wherein each of the first set of molecules lacks a reactive group capable of binding to a nucleoside; applying electromagnetic radiation (EMR) to predetermined regions of the surface, wherein the EMR comprises a wavelength from about 100 nm to about 300 nm, wherein application of the EMR results in removal of the first set of molecules at the predetermined regions, thereby defining loci for oligonucleic acid extension; synthesizing a plurality of oligonucleic acids from the surface, wherein each oligonucleic acid extends from a different locus, and wherein the different loci are at least about 75% uniform when measured by calculating amplitude of signal variation for oligonucleic acids extending from each locus divided by total signal intensity following white light illumination using an optical microscope; and assembling the plurality of genes from the plurality of oligonucleic acids. Further provided are methods wherein greater than about 90% of the first set of molecules are removed at the predetermined regions of the surface following application of EMR. Further provided are methods wherein about 100% of the first set of molecules are removed at the predetermined regions of the surface following application of EMR. Further provided are methods wherein the predetermined regions have a width of about 1 to about 500 um. Further provided are methods wherein the predetermined regions have a width of about 1 to about 100 um. Further provided are methods wherein the predetermined regions have a width of about 3 um to about 60 um. Further provided are methods wherein the predetermined regions have a width of at least 3 um. Further provided are methods wherein the predetermined regions have a perimeter that is a circle or a rectangle in shape. Further provided are methods wherein the first set of molecules comprises a fluorosilane. Further provided are methods wherein the first set of molecules comprises perfluorooctyltrichlorosilane, octylchlorosilane, octadecyltrichlorosilane, (tridecafluoro-1,1,2,2-tetrahydrooctyl)trichlorosilane, or tridecafluoro-1,1,2,2-tetrahydrooctyl)trimethoxysilane. Further provided are methods further comprising applying a second set of molecules to the surface after application of the EMR, wherein each of the second set of molecules binds to the predetermined regions of the surface and comprises a reactive group capable of binding to a nucleoside. Further provided are methods wherein the second set of molecules comprises an aminosilane. Further provided are methods wherein the second set of molecules comprises N-(3-triethoxysilylpropyl)-4-hydroxybutyramide (HAPS), 11-acetoxyundecyltriethoxysilane, n-decyltriethoxysilane, (3-aminopropyl)trimethoxysilane, (3-aminopropyl)triethoxysilane, 3-glycidoxypropyltrimethoxysilane (GOP S), or 3-iodo-propyltrimethoxysilane. Further provided are methods wherein each of the oligonucleic acids comprises about 25 bases to about 2 kb in length. Further provided are methods wherein each of the oligonucleic acids comprises about 25 bases to about 150 bases in length. Further provided are methods wherein each locus comprises a population of oligonucleic acids about 80% uniform when measured by calculating amplitude of signal variation for oligonucleic acids extending from each locus divided by total signal intensity following white light illumination using an optical microscope. Further provided are methods wherein the oligonucleic acids extending from the different loci collectively encode sequence for a preselected gene. Further provided are methods wherein the EMR comprises a wavelength from about 150 nm to about 200 nm. Further provided are methods wherein the EMR has a wavelength of about 172 nm. Further provided are methods wherein the surface is substantially planar. Further provided are methods wherein the surface comprises microstructures. Further provided are methods wherein the microstructures comprise channels or wells. Further provided are methods wherein the EMR is emitted from a lamp or a laser. Further provided are methods wherein the lamp comprises an emission source in the shape of a cylinder or a flat panel. Further provided are methods wherein the flat panel has a surface area that is at least 36 inches squared. Further provided are methods wherein the plurality of oligonucleic acids synthesized on the surface are arranged in clusters of the different loci, wherein each cluster comprises oligonucleic acids encoding sequence for a single gene. Further provided are methods wherein the plurality of genes comprises at least 50, 240, or 5000 genes. 
     INCORPORATION BY REFERENCE 
     All publications, patents, and patent applications disclosed herein are incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference. In the event of a conflict between a term disclosed herein and a term in an incorporated reference, the term herein controls. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  depicts a schematic process flow for the functionalization of a surface with two different coating materials patterned using electromagnetic radiation (EMR). 
         FIG. 2A  depicts a detailed view of part of the process flow illustrated in  FIG. 1 . 
         FIG. 2B  depicts a detailed view of part of the process flow illustrated in  FIG. 1 . 
         FIG. 3  depicts the process flow illustrated in  FIG. 1  performed on a surface comprising wells. 
         FIG. 4  depicts a schematic process flow for the functionalization of a surface with two different coating materials patterned using EMR. 
         FIG. 5  depicts the process flow illustrated in  FIG. 4  performed on a surface comprising channels. 
         FIG. 6  depicts a schematic process flow for the functionalization of a surface with a passive and an active agent, wherein a layer of oligonucleic acids is extended from the actively functionalized surface. 
         FIG. 7A  shows an exemplary laser set up using a conveyer belt to move the belt for exposure to the laser in the desired regions. 
         FIG. 7B  shows an exemplary laser set up using a conveyer belt to move the plates for exposure to the laser in the desired regions. 
         FIG. 7C  shows an exemplary laser set up using a reel to reel mechanism to move the chip for exposure to the laser in the desired regions. 
         FIG. 7D  shows an exemplary laser set up using a flat plate to hold the chip for exposure to the laser. 
         FIG. 8  illustrates a process workflow for gene synthesis on a patterned surface comprising distinct regions of active and passive functionalization. Oligonucleic acids are synthesized on actively functionalized regions of the surface, removed from the surface, assembled into a gene using polymerase chain assembly (PCA), and the assembled gene product is amplified. Errors in the gene product sequence are corrected and the corrected products amplified and processed. Amplified, corrected gene products are sequenced and released for shipment. 
         FIG. 9  illustrates a computer system. 
         FIG. 10  illustrates is a block diagram for architecture of a computer system. 
         FIG. 11  is a diagram demonstrating a network configured to incorporate a plurality of computer systems, a plurality of cell phones and personal data assistants, and Network Attached Storage (NAS). 
         FIG. 12  is a block diagram of a multiprocessor computer system using a shared virtual address memory space. 
         FIG. 13  is a graph of contact angles measured from the surface of a silicon dioxide surface after various steps of a differential functionalization process, the process comprising: coating the surface with a fluorosilane passive layer, patterning by selective exposure to deep UV light, and coating with a GOPS active layer. Trace A corresponds to contact angles measured after the surface was coated with a layer of fluorosilanes. Trace B corresponds to contact angles measured after the surface was exposed to deep UV light through a shadow mask. Trace C corresponds to contact angles measured after the surface was coated with GOPS. 
         FIG. 14  is an image capture of a surface differentially functionalized with an active and a passive layer, wherein the active layer is a support for synthesized oligonucleic acids. The areas of the surface comprising synthesized oligonucleic acids appear clear while areas of the surface which are dark correspond to the passive layer. 
         FIG. 15  is an image capture of a differentially functionalized surface after oligonucleic acid synthesis, wherein an active layer of the surface is a support for the synthesized oligonucleic acids. The areas of the surface comprising synthesized oligonucleic acids appear clear while areas of the surface which are coated with a passive layer appear dark. 
         FIG. 16  shows image captures of surfaces differentially functionalized with an active and passive layer by different process steps. 
         FIG. 17A  is a plot of DNA intensity profiles for oligonucleic acids synthesized on a surface functionalized using a forward photoresist process as described in Example 5. The plot has a top line, a middle line, and a bottom line. Each line represents an intensity signal obtained from a different light sensor on a camera after exposure to white light. The center line corresponds to the sensor with the most effective contrast for the sample oligonucleotides on the chip. 
         FIG. 17B  is a plot of DNA intensity profiles for oligonucleic acids synthesized on a surface functionalized using a reverse photoresist process as described in Example 5. The plot has a top line, a middle line, and a bottom line. Each line represents an intensity signal obtained from a different light sensor on a camera after exposure to white light. The center line corresponds to the sensor with the most effective contrast for the sample oligonucleotides on the chip. 
         FIG. 17C  is a plot of DNA intensity profiles for oligonucleic acids synthesized on a surface functionalized using a deep UV process as described in Example 5. The plot has a top line, a middle line, and a bottom line. Each line represents an intensity signal obtained from a different light sensor on a camera after exposure to white light. The center line corresponds to the sensor with the most effective contrast for the sample oligonucleotides on the chip. 
         FIG. 18  shows an exemplary setup for the functionalization of a surface with two different coating materials patterned using EMR. 
         FIG. 19  shows an alternative view of the exemplary setup in  FIG. 18 . 
         FIG. 20  shows a flat lamp having a distance between the lamp and the chip that is equidistant over the entire surface. 
         FIG. 21  shows a cylindrical lamp, similar to an Ushio lamp, having a distance between the lamp and the chip that is closer at the center than at either edge. 
         FIG. 22  shows a chip after writer synthesis of oligonucleotides extending form  121  discrete loci. In this view of the chip, the alignment is shown on the chip&#39;s fiducials  2101 . 
         FIG. 23  depicts plots from a TOF-SIMS analysis of an area 150 um×150 um of a silicon dioxide chip (bottom), with a fluorosilane coating (top), and after DUV removal of the functional group (middle). The Y axis is for Intensity counts and the X axis is for Mass (u). 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure provides for devices, compositions, methods and systems related the patterning of the surface of a structure utilizing electromagnetic radiation (EMR) to remove a material bound to a surface of the structure at select regions to generate a desired pattern of the material on the surface. Methods described herein provide for the generation of surfaces having differential chemical coatings in a timeframe that is faster than conventional methods. In addition, described herein are methods where the resultant populations extending from sites for nucleic acid extension (loci) provide for highly uniform nucleic acid populations. Methods described herein provide for the generation of a library of synthesized oligonucleic acids, comprising a plurality of different oligonucleic acids, each different oligonucleic acid extending from a structure at a different loci, wherein the different loci are at least about 75% uniform when measured by calculating amplitude of signal variation for oligonucleic acids extending from each locus divided by total signal intensity following white light illumination using an optical microscope. Synthesized nucleic acid populations synthesized by methods described herein can be used for downstream applications, such as gene assembly or PCR mutagenesis. For example, Further provided herein are methods for gene synthesis, the methods comprising providing predetermined sequences for a plurality of oligonucleic acids, wherein the plurality of oligonucleic acids collectively encode for a plurality of genes; synthesizing a plurality of oligonucleic acids from the surface, wherein each oligonucleic acid extends from a different locus, and wherein the different loci are at least about 75% uniform when measured by calculating amplitude of signal variation for oligonucleic acids extending from each locus divided by total signal intensity following white light illumination using an optical microscope; and assembling the plurality of genes from the plurality of oligonucleic acids. 
     Definitions 
     Throughout this disclosure, various embodiments are presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of any embodiments. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range to the tenth of the unit of the lower limit unless the context clearly dictates otherwise. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual values within that range, for example, 1.1, 2, 2.3, 5, and 5.9. This applies regardless of the breadth of the range. The upper and lower limits of these intervening ranges may independently be included in the smaller ranges, and are also encompassed within the invention, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included, unless the context clearly dictates otherwise. 
     The terminology used herein is for the purpose of describing particular instances only and is not intended to be limiting of any embodiment. As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     Unless specifically stated or obvious from context, as used herein, the term “about” in reference to a number or range of numbers is understood to mean the stated number and numbers +/−10% thereof, or 10% below the lower listed limit and 10% above the higher listed limit for the values listed for a range. 
     Surface Functionalization with EMR 
     Generally, patterned regions on the surface of a structure are prepared by exposing a coated region of the surface to EMR through a patterned shadow mask. In such cases, the material coated on the surface is removed in exposed areas and not removed in the mask-protected area. As a result, the pattern of the shadow mask is transferred onto the surface chemistry of the structure. In some instances, EMR removes a material coated on a surface by cleaving the chemical bonds between the surface and the bound coating material by photolysis. In some cases, EMR is deep UV light. Without wishing to be bound by theory, in some instances, for surfaces with organic molecules bound thereto, ozone generated from deep UV light in the presence of oxygen facilitates the removal of the organic molecules from the surface. Alternatively, patterned regions on the surface of a structure are prepared by exposing a coated surface to a laser beam. In such cases, the material coated on the surface is removed in the exposed areas and not removed in the non-exposed areas. As a result, the pattern as defined by the laser exposed areas is transferred onto the surface chemistry of the structure. 
     In some instances, patterning results in differential functionalization of a surface, where two or more different regions of the surface are functionalized to have a chemistry different from one another. In such cases, a surface is patterned by applying a first set of molecules having a first chemistry to the surface, followed by removal of select regions of the first set of molecules via exposure to EMR through a shadow mask. The surface is subsequently coated with a second set of molecules having a second chemistry at the select regions lacking the first set of molecules. The first and second set of molecules have different affinities for binding to biopolymers, and therefore provide for a surface with a patterned coating are predetermined regions for biopolymer extension. In some cases, the biopolymer is an oligonucleic acid. 
     In some instances, a surface is patterned so that one or more regions is coated with an active agent and one or more regions of its surface is coated with a passive agent, wherein the active agent comprises a functional group that binds to a target molecule and the passive agent lacks a functional group capable of binding to the target molecule. In the context of surfaces for biopolymer extension, a region comprising an active agent (i.e. an active functionalization area) is one that provides support for the coupling of a first monomer in an extension reaction. In some instances, the first monomer is a phosphoramidite nucleoside an oligonucleic acid extension reaction. 
     Provided herein are methods where a functionalized surface is patterned by application of EMR to specific regions of the surface to selectively remove bound functionalization agent via photolytic cleavage. Cleavage of a bound agent from a surface at specific regions is achieved, in some instances, by applying EMR to the surface through a shadow mask. A shadow mask protects areas of a surface from EMR so that bound agents at those areas are not subject to photolysis by EMR. Masks are comprised of any suitable material that does not transmit EMR. In some instances, a shadow mask comprises chrome on quartz. In some instances, a shadow mask comprises chrome on high UV transmission quartz. In some instances, a shadow mask comprises a dielectric layer on high UV transmission quartz. In some instances, a shadow mask comprises a dielectric layer on High UV transmission LiF or MgF 2 . In some instances, a pattern of a functionalization agent on a surface is defined by a pattern of a shadow mask. For example, a shadow mask comprises a plurality of openings that correspond to desired features of a surface. In such instances, dimensions of a shadow mask openings used in the functionalization methods described herein correspond to dimensions of a surface feature as described elsewhere herein. 
     In some instances, patterning a surface bound with a functionalization agent comprises overlaying a shadow mask onto the surface and applying EMR through open regions of the mask. In some instances, a shadow mask is positioned directly on top of a surface for patterning, minimizing exposure of unintended surface regions to applied light. In some cases, the distance between an EMR source and a shadow mask is less than about 100 mm, 10 mm, 5 mm, 1 mm, or 0.5 mm. 
     In various aspects, a functionalized surface is patterned by application of EMR via a laser to specific regions of the surface to selectively remove bound functionalization agent via photolytic cleavage. Cleavage of a bound agent from a surface at specific regions is achieved by beam deflection and/or by moving the sample (e.g., with an X-Y or an X-Y-Z-stage, capable of moving in two or three dimensions, respectively) and use of the laser shutter to turn laser on and off using a specific exposure time or dose in a controlled environment along the optical path of the laser and around the substrate. In some instances a substrate is introduced into a guiding system which is contained within a controlled environment. In some instances, the substrate is aligned to a reference for exposure to the laser beam and a controlled atmosphere is created at the substrate to be exposed and in the laser path. In some instances, the substrate is moved in a synchronized way with laser pulses and deflection and a pattern is thereby created on the substrate. 
     In some instances, exposure of a surface to EMR is performed in an oxygen controlled environment. In some cases, the environment is devoid of oxygen. Ozone generated from oxygen during EMR exposure assists with photolysis of bound agents. However, oxygen also absorbs light and therefore also reduces cleavage efficiency. Therefore, in some instances, oxygen is maintained at a controlled level, or removed, during surface patterning with EMR exposure. In some cases, oxygen is removed in the area located between the EMR source and the shadow mask. 
     In some instances, EMR is applied towards a surface at a wavelength from about 100 nm to about 400 nm, from about 100 nm to about 300 nm, or from about 100 nm to about 200 nm. For example, EMR is applied at an ultraviolet (UV) wavelength, or a deep UV wavelength. In some instances, deep UV light is applied to a surface at a wavelength of about 172 nm to cleave a bound agent from the surface. In some instances, EMR is applied with a xenon lamp. Exposure distance is a measurement between the lamp and the surface. In some instances, the exposure distance is about 0.1 to 5 cm. In some instances, the exposure distance is about 0.5 to 2 cm. In some instances, the exposure distance is about 0.5, 1, 2, 3, 4, or 5 cm. In some instances, EMR is applied with a laser. Exemplary lasers and their wavelengths include but are not limited to Ar 2  (126 nm), Kr 2  (146 nm), F 2  (157 nm), Xe 2  (172 and 175 nm), ArF (193 nm). 
     In some instances, processes described herein provide for generation of patterned surfaces with loci (sites for oligonucleic acid extension) providing a support for synthesis of oligonucleic acid populations, wherein a measurement across multiple loci show that the oligonucleic acid populations have at least about 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 90, 95 or greater percent (%) uniformity, when measured by calculating amplitude of signal variation for oligonucleic acids extending from each locus divided by total signal intensity following white light illumination using an optical microscope. In some instances, uniformity is measured using a camera capable of recording white light emissions, e.g., a Nikon DS Fi2 camera. White light illumination may fall in the range of about 400 nm to about 700 nm. In some instances, the camera has sensitivity for wavelengths in the range of about 450 nm to about 620 nm. In some instances, the camera has sensitivity for wavelengths in the range of about 480 nm to about 550 nm. In some instances, the camera has sensitivity for wavelengths in the range of about 500 nm to about 530 nm. In some instances, the percent uniformity is about 77%. In some instances, the percent uniformity is at least about 75%. In some instances, the percent uniformity is about 80%. In some instances, processes described herein provide for light-based removal of at least about 80, 81, 82, 83, 84, 85, 86, 87, 88, 90, 91, 92, 93, 94, 95 or greater percent (%) of functionalization agent deposited at a preselected region following exposure to EMR. 
     In some instances, photolysis by EMR removes at least about 50%, 60%, 70%, 80%, 90%, 95%, 98%, 99% or virtually all of a bound agent exposed to the EMR during a surface patterning process described herein. In some instances, photolysis by EMR removes at least about 90% of a bound agent exposed to the EMR during the surface patterning process. In some instances, photolysis by EMR removes about 100% of a bound agent exposed to the EMR during the surface patterning process. Different parameters of an EMR application method are adjustable according to the requirements for cleaving the bond between a functionalization agent and a reactive group of a surface. In some instances, EMR is applied as deep UV light at an intensity between 10 and 200 mW/cm 2 , 10 and 100 mW/cm 2 , 10 and 50 mW/cm 2 , or 10 and 50 mW/cm 2 . In some instances, EMR is applied to a surface between 30 seconds and 300 seconds, 30 seconds and 240 seconds, 30 seconds and 180 seconds, 30 seconds and 120 seconds, or 30 seconds and 60 seconds. 
     Lamps 
     Provided herein are methods for functionalizing a surface with one or more chemistries in a desired pattern using electromagnetic radiation (EMR). Exemplary workflows for differentially functionalizing surfaces on structures described herein a described in the following paragraphs. A first process workflow provides for functionalization of a surface with two coating materials having different chemistries ( FIG. 1 ). This first workflow is divided generally into the following process steps: (A) surface preparation; (B) deposition of a first set of molecules on the surface; (C) patterning by cleaving the first set of molecules from the surface at regions exposed to EMR applied by a lamp through a shadow mask; (D) removal of the cleaved first set of molecules; and (E) deposition of a second set of molecules to the regions where the first set of molecules was removed. 
     In the first stage of the first process workflow, a structure  100  is provided having a surface  101  comprising a layer of reactive functional groups that bind with a subsequently applied coating material. In this case, a surface  101  comprises a layer of silicon dioxide that is reactive with both a first and a second set of molecules. The surface  101  is optionally cleaned in a wet and/or dry process to remove organic contaminants. In some instances, the surface is cleaned with plasma, wherein oxygen plasma is applied to the surface. In some instances, the surface is cleaned by applying an oxidizing agent to the surface to both clean and hydroxylate the surface. An exemplary oxidizing agent is a piranha solution comprising a mixture of sulfuric acid and hydrogen peroxide. 
     The prepared surface  100  is deposited with a first set of molecules  102  comprising an agent reactive with the functional groups of surface  101 , generating a surface bound with a layer of the first set of molecules ( FIG. 1 , part B). The surface is subsequently patterned by removing the first set of molecules from defined regions  103  of the surface by exposing said regions to EMR  105  ( FIG. 1 , part C). In some cases, the EMR is deep UV light. A shadow mask  104  is positioned over the surface so that only defined regions  103  are exposed to the EMR  105  through openings  106  in the shadow mask. The layer of first set of molecules bound to the exposed regions of the surface is cleaved from the surface and washed away with an appropriate wash solution ( FIG. 1 , part D). The surface is then dried in preparation for a subsequent process step. 
     After the surface  101  is patterned with a first set of molecules via EMR, functional groups of the surface exposed distinct regions  103  lacking the first set of molecules are reacted with a second set of molecules  107  deposited onto the surface ( FIG. 1 , part E). In some instances, the second set of molecules comprises an active agent having a functional group that is reactive with a nucleoside while the first set of molecules comprises a passive agent that lacks a functional group reactive with a nucleoside. Therefore, in some instances, the first process workflow exemplifies a method for patterning distinct regions of a surface for nucleoside attachment and subsequent oligonucleic acid extension from the attached nucleoside. In some instances, a distinct region of a surface comprising an active agent is a locus of the surface. 
     In a second process workflow, a structure  201  having a surface  202  comprising a reactive layer of organo-silane (—O—Si—C) is coated with a layer of a first set of molecules, R ( FIG. 2A , part A). Upon application of EMR through a patterned shadow mask, exposed first set of molecules is cleaved from the surface, as shown by the free C-R groups of  FIG. 2 , part B. The cleaved first set of molecules is washed away to reveal a patterned surface having functionalized regions comprising a first set of molecules (—O—Si—C-R) and exposed silicon oxide regions (—O—Si). The exposed silicon oxide regions are re-oxidized in preparation for a reaction with a second set of molecules. A layer of a second set of molecules, R2, is deposited onto the surface  201  of the structure  201  to generate regions functionalized with the second set of molecules (—O—Si—O—Si—C-R2) ( FIG. 2B ). In some instances, a Si—O bond is cleaved, in addition to or as an alternative to cleavage of the C-R group, and the second set of molecules is deposited onto an original reactive group of the surface (e.g., a hydroxyl, thiol, or amine group). In some instances, the first set of molecules comprises a passive agent non-reactive with a biomolecule. In some instances, the second set of molecules comprises an active agent reactive with a biomolecule. 
     Surfaces illustrated in  FIG. 1  and  FIGS. 2A-2B  comprise substantially planar surfaces. In some instances, differential functionalization methods described herein are applied to surfaces comprising three-dimensional elements. Three-dimensional elements include both features raised and recessed. Example three-dimensional elements include, without limitation, wells, channels/pores, and posts. Example three-dimensional shapes include, without limitation, circles, squares, rectangles, ovals, and triangles that have a depth or a height. Example two-dimensional (or substantially planar shapes), include, without limitation, circles, squares, rectangles, ovals, and triangles. 
     In a third process workflow ( FIG. 3 ), a differential functionalization method is performed on a structure comprising three-dimensional features  301 . In this case, a surface comprising wells  303  layered with a first set of molecules  302 , wherein the first set of molecules  304  comprises an agent that binds to reactive functional groups on the surface. A shadow mask  305  comprising openings in a pattern defining the wells of the surface is positioned over the top surface of the surface and EMR is applied through the mask  306 . EMR treatment results in cleavage of the first set of molecules from the wells and the residual material is washed away to generate a surface comprising a surface coated with a layer of the first set of molecules and wells having surfaces that lack a layer of the first set of molecules  307 . A second set of molecules  308  is deposited onto the surface where the material chemically reacts with the exposed reactive functional groups on the well surfaces to form a layer of the second set of molecules along the well surfaces  309 . In some instances, the first set of molecules comprises a passive agent non-reactive with a biomolecule. In some instances, the second set of molecules comprises an active agent reactive with a biomolecule. In some instances, a three-dimensional surface comprises regions of active functionalization confined to the surface of the wells. In some cases, the actively functionalized wells are reactive to a nucleoside and support the attachment and synthesis of an oligonucleic acid. 
     In some instances, a patterning process disclosed herein comprises sequentially applying a first material comprising a passive agent to a surface, and applying a second set of molecules comprising an active agent to a surface. In some instances, a patterning process exemplified by any of  FIGS. 1-3  comprises sequentially applying a first material comprising an active agent to a surface, and applying a second material comprising a passive agent to a surface. In some instances, a patterning process, as illustrated by any of  FIGS. 1-3 , is modified to omit application of a first or second material to a surface. For example, a first material is patterned on a surface with EMR and regions of the surface lacking the first material are modified by a chemical reaction that does not comprise deposition of a material. 
     In some cases, a material deposited on the surface comprises both an active and a passive agent. In some cases, both a first material and a second material comprise an active agent. In some cases, both a first material and a second material comprise a passive agent. In some instances, a material deposited on the surface comprises an active agent that is deactivated or not reactive to chemistries with a biomolecule (i.e. a non-activated, active agent). 
     In a fourth process workflow, a surface is patterned with regions of active functionalization in a method that comprises: depositing a non-activated, active agent to a surface, patterning with EMR, and activating the active agent ( FIG. 4 ). This workflow is divided generally into the following processes: (A) surface preparation; (B) reacting a non-activated, active agent of a first set of molecules with a reactive functional group of the surface; (C) patterning the surface by cleaving the first set of molecules from the surface at regions exposed to EMR applied through a shadow mask; (D) deposition of a second set of molecules to the regions where the first set of molecules was removed; and (E) activation of the non-activated, active agent. In some implementations, one or more of the workflow processes are optional and/or modified according to the requirements of the treated surface. 
     In this workflow, a structure  401  comprises a surface  402 . The surface  402  is optionally cleaned in a wet and/or dry process to remove organic contaminants. A first set of molecules  403  comprising a non-activated, active agent is deposited onto surface  402 , where it binds with the reactive functional groups of the surface to produce a non-activated, active layer across the surface ( FIG. 4 , part B). The non-activated, active layer is subsequently patterned ( FIG. 4 , part C) by cleaving the non-activated, active layer from defined regions  404  of the surface during exposure of said regions to EMR  405 . A shadow mask  406  is positioned over the surface so that the defined regions  404  are exposed to EMR  405  through openings  407  in the shadow mask. The cleaved, non-activated, active material is removed from the surface by washing, followed by a drying step (not shown). A second set of molecules  408  is deposited onto the surface to react with surface functional groups at exposed defined regions  404  to form a patterned layer of second set of molecules ( FIG. 4 , part D). The non-active, active agent is activated by application of an activating reagent  409  to the surface ( FIG. 4 , part E). In some instances, activated regions of the functionalized surface support the attachment of a nucleic acid monomer, while the remaining regions are non-reactive to nucleic acid monomer. 
     In some instances, the fourth process workflow for a patterning method is applied to a surface comprising three-dimensional features. In some cases, three-dimensional features include channels  503  providing fluid communication between two or more surfaces of a structure  501 . In a first step, a surface is bound with a layer of a first set of molecules  502  comprising a non-activated, active agent ( FIG. 5 , part A). A shadow mask  504  comprising openings in a pattern defining the features of the surface is positioned over the surface and EMR  505  is applied through the mask ( FIG. 5 , part B). After EMR cleavage of layer of the non-activated active agent from exposed regions of the channels, the residual agent is washed away. A second set of molecules  506  is deposited onto the surface, chemically reacting with the exposed surfaces of the channels to generate a differentially functionalized surface ( FIG. 5 , part C). In some instances, the non-active, active agent is activated. In some instances, activated regions of the functionalized surface prepared in the manner described above support the attachment of a nucleic acid monomer to its surface, while the remaining regions are non-reactive to the nucleic acid monomers. 
     In in a fifth process workflow, a surface of a structure is patterned to comprise region(s) functionalized with an active agent and different region(s) functionalized with a passive agent, wherein an actively functionalized region is bound to an oligonucleic acid layer. In some cases, this oligonucleic acid layer is a platform onto which an oligonucleic acid of predetermined sequence is extended from during an oligonucleic acid synthesis reaction. In some cases, oligonucleic acids of the platform comprise from about 10 to about 100 nucleobases having a shared oligonucleic acid sequence or a plurality of different sequences. The length and identity of the oligonucleic acid platform is tunable depending on the needs of the surface and/or identity of the oligonucleic acids to be extended from said platform. This workflow is divided generally into the following processes: (A) surface preparation; (B) deposition of a first set of molecules comprising an active agent to the surface to bind with the surface; (C) extension of an oligonucleic acid platform from a layer of bound active agent; (D) patterning the surface by cleaving the active agent and oligonucleic acid platform layers from the surface at regions exposed to EMR applied through a shadow mask; (E) deposition of a second set of molecules to the regions where the active layer was removed; and (F) extension of a predetermined oligonucleic acid sequence from the platform oligonucleic acid ( FIG. 6 ). In some implementations, one or more of the workflow processes are optional and/or modified according to the requirements of the treated surface. 
     Referring to  FIG. 6 , a structure  601  is provided comprising a surface  602 . In some instances, surface  602  is prepared prior to application of a coating material by a wet or dry cleaning process. In some cases, the surface  602  is deposited with a first set of molecules comprising an active agent  603  that is reactive both with the functional groups of the surface  602  and a nucleoside. The bound active agent is reacted with a nucleobase and an oligonucleic acid layer is extended from the active agent surface to generate an oligonucleic acid platform  604 . A protecting group is applied to the terminal end of the oligonucleic acid platform (not shown). The layers of active agent and oligonucleic acid platform are subsequently patterned by removing said layers from defined regions  605  of the surface via exposure to EMR  606 . A shadow mask  607  is positioned over the surface so that only the defined regions  605  are exposed to EMR  606  through openings  608  in the shadow mask. The layers of active agent and platform oligonucleic acids coated on the exposed regions of the surface are cleaved from the surface and washed away with an appropriate wash solution. After the surface is patterned, surface functional groups of exposed regions  605  are reacted with a second set of molecules  609  deposited onto the surface  602 , resulting in a differentially functionalized surface comprising actively functionalized regions having an oligonucleic acid platform extended therefrom. The platform oligonucleic acids are de-protected and extension of a predetermined sequence of oligonucleic acids  610  from the platform is performed. 
     Lasers 
     Provided herein are methods for surface functionalization where EMR is provided by a laser, which does not require use of a shadow mask. Generally the process steps comprise: (A) surface preparation; (B) deposition of a first set of molecules on the surface; (C) patterning by cleaving the first set of molecules from the surface at regions exposed to EMR applied by a laser; (D) removal of the cleaved first set of molecules; and, optionally, (E) deposition of a second set of molecules to the regions where the first set of molecules was removed. 
     A benefit of using a laser is that EMR is applied to the surface at specific locations and does not require a shadow mask. In contrast to a lamp, a shutter is used to regulate ERM exposure while the substrate structure (e.g., a plate or flexible surface) moves. In this arrangement, the speed and direction of movement for the substrate structure, in combination with the angle and position of the laser, are factors in determining surface patterning. 
     Referring to  FIG. 7A , a conveyer belt  701  is provided. The conveyer belt  701  is moved using two rollers  703  at either end of the conveyer belt  701  in order to move the conveyer belt  701 . The belt, or a material on the belt, has regions selected for surface patterning by light emission methods described herein. In some instances, the conveyor belt comprises nylon, or a separate layer on top of the belt comprising nylon. In some instances, a layer of passive functionalization agent described herein is first deposited on the surface of the belt. The movement of the conveyer belt  701  is coordinated with timing of a shutter in the laser emitting device  713 , such that the substrate material is exposed to the laser beam  711  in the specific areas of that require EMR exposure. The cleaved molecules are removed from the surface by washing, followed by a drying step. A second set of molecules is deposited onto the surface to react with surface functional groups at exposed defined regions to form a patterned layer of second set of molecules. The second set of molecules are active functionalization agents which comprises a reactive groups capable of binding the surface and also coupling to nucleosides. In an alternative arrangement ( FIG. 7B ), the conveyer belt  701  comprises a rigid material, such as small plates  705 , which regions preselected for surface patterning. In some instances, rigid plates are silicon. Referring to  FIG. 7C , a tape  709  is moved using a reel-to-reel controller  715 . In some cases, the tape is exposed to the light source in a similar manner, resulting in the tape having a chemically patterned surface. Referring to  FIG. 7D , a flat surface  717  is provided (e.g., a silicon plate) for exposure to a laser beam  711  controlled by a laser emitting device  713 . The laser emitting device  713  is moved in coordination with a shutter in the laser emitting device  713  such that the plate is exposed to the laser beam  711  in the specific areas of the plate. In alternative methods, a surface described herein is first treated with an active functionalization layer, followed by light based cleavage, and treatment with a passive functionalization agent. In some arrangements, to expose different locations of the plate, the laser source is either deflected or the chip is moved along X-Y or X-Y-Z axis. In some instances, the third, fourth, or fifth patterning process workflow comprises sequentially applying a first set of molecules comprising an active agent to a surface, patterning with EMR, and applying a second set of molecules comprising a passive agent to a surface. In some instances, the third, fourth, or fifth patterning process workflow comprises sequentially applying a first set of molecules comprising a passive agent to a surface, patterning with EMR, and applying a second set of molecules comprising an active agent to a surface. In some instances, the third, fourth, or fifth patterning process workflow is modified to omit application of a first or second set of molecules to a surface. In some cases, a first set of molecules and/or a second set of molecules comprise both an active and a passive agent. In some cases, both a first set of molecules and a second set of molecules comprise an active agent. In some cases, both a first set of molecules and a second set of molecules comprise a passive agent. 
     Exemplary active agents for inclusion in a set of molecules described herein include, without limitation, N-(3-triethoxysilylpropyl)-4-hydroxybutyramide (HAPS), 11-acetoxyundecyltriethoxysilane, n-decyltriethoxysilane, (3-aminopropyl)trimethoxysilane, (3-aminopropyl)triethoxysilane, 3-glycidoxypropyltrimethoxysilane (GOPS), 3-iodo-propyltrimethoxysilane, butyl-aldehydr-trimethoxysilane, dimeric secondary aminoalkyl siloxanes, (3-aminopropyl)-diethoxy-methylsilane, (3-aminopropyl)-dimethyl-ethoxysilane, and (3-aminopropyl)-trimethoxysilane, (3-glycidoxypropyl)-dimethyl-ethoxysilane, glycidoxy-trimethoxysilane, (3-mercaptopropyl)-trimethoxysilane, 3-4 epoxycyclohexyl-ethyltrimethoxysilane, and (3-mercaptopropyl)-methyl-dimethoxysilane, allyl trichlorochlorosilane, 7-oct-1-enyl trichlorochlorosilane, or bis (3-trimethoxysilylpropyl) amine. A passive agent for inclusion in a set of molecules described herein includes, without limitation, perfluorooctyltrichlorosilane; tri decafluoro-1,1,2,2-tetrahydrooctyl)trichlorosilane; tridecafluoro-1,1,2,2-tetrahydrooctyl)trimethoxysilane; 1H, 1H, 2H, 2H-fluorooctyltriethoxysilane (FOS); trichloro(1H, 1H, 2H, 2H-perfluorooctyl)silane; tert-butyl-[5-fluoro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)indol-1-yl]-dimethyl-silane; CYTOP™; Fluorinert™; perfluoroctyltrichlorosilane (PFOTCS); perfluorooctyldimethylchlorosilane (PFODCS); perfluorodecyltriethoxysilane (PFDTES); pentafluorophenyl-dimethylpropylchloro-silane (PFPTES); perfluorooctyltriethoxysilane; perfluorooctyltrimethoxysilane; octylchlorosilane; dimethylchloro-octodecyl-silane; methyldichloro-octodecyl-silane; trichloro-octodecyl-silane; trimethyl-octodecyl-silane; triethyl-octodecyl-silane; or octadecyltrichlorosilane. 
     In some instances, a region of active functionalization comprises a combination of active and passive agents so that the actively functionalized region comprises a lower density of active functionalization agent than a region reacted with just an active agent. Similarly, in some instances, two or more active agents are combined to modulate the surface properties of the actively functionalized area. In some instances, an actively functionalized surface is prepared for oligonucleic acid synthesis, and by modulating the density of the active agents on a surface of a structure, the density of oligonucleic acids extending from said surface is modulated. 
     In any of the surfaces disclosed here, oligonucleic acid extension steps include extension of at least about 10, 25, 50, 75, 100, 125, 150, 200, 500, 1000, 2000 or more bases in length. In some instances, oligonucleic acid of about 25 bases to 2 kb, 25 bases to 150 bases, or 25 bases to 500 bases, in length are synthesized. 
     Microcontact Printing 
     Provided herein are methods for surface functionalization to directly apply an active agent and/or a passive agent to a selected surface using microcontact printing of an active agent and/or a passive agent onto the selected surface, such as a plate (e.g., a silicon plate), at the specific areas of the surface that require the active agent and/or the passive agent. Active functionalization of a surface involves microcontact printing of an active functionalization agent, or active agent, to the surface, where the agent binds to a functional group of the surface. Passive functionalization of a surface involves microcontact printing of a passive functionalization agent, or passive agent, to the surface, where the agent binds to a functional group of the surface. In some instances, an active functionalization agent binds to a reactive group on a surface and comprises a functional group that is reactive with a specific biomolecule, thereby supporting a coupling reaction to the surface. As used herein, “inking” a stamp for microcontact printing refers to depositing on a stamp an agent to be applied to a surface, such as an active agent or a passive agent as described herein. In an alternative arrangement, a similar method of microcontact printing is performed on a flexible surface, e.g., a tape or conveyor belt. 
     In an exemplary workflow of patterning a passive agent on a plate (e.g., a silicon plate), polydimethylsiloxane (PDMS) stamps are made using a UV photolithography process. A silicon wafer coated with photoresist is exposed to UV light through a mask, creating a pattern on the silicon wafer. The exposed wafer is then exposed to a solution of developer creating a master which is used to cast the PDMS stamp. The PDMS prepolymer is mixed with a curing agent and poured onto the prepared master. The cured stamp is then peeled from the template and is ready for inking. The finished stamp is about 100 μm to about 1 cm thick and the raised portions of the stamp range from about 1 μm to about 500 μm. In an alternative arrangement, a similar method of microcontact printing is performed on a flexible surface, e.g., a tape or conveyor belt. 
     Stamps are inked with a solution containing a passive agent, for example, tridecafluoro-1,1,2,2-tetrahydrooctyl)trichlorosilane, or tridecafluoro-1,1,2,2-tetrahydrooctyl)trimethoxysilane. After inking, the passive agent solution is transferred to a plate. Care is taken to not deform the stamp while stamping the microchip. Each inked stamp is used to pattern three microchips before reloading the stamp. Alternatively, ink is continuously applied to a patterned roller stamp and the ink is transferred from the roller to a moving belt. In an alternative arrangement, a similar method of microcontact printing is performed on a flexible surface, e.g., a tape or conveyor belt. The active agent is then deposited on the non-treated areas using CVD. 
     In an alternative workflow of patterning an active agent onto a silicon plate, polydimethylsiloxane (PDMS) stamps are made using a UV photolithography process. A silicon wafer coated with photoresist is exposed to UV light through a mask, creating a pattern on the silicon wafer. The exposed wafer is then exposed to a solution of developer creating a master which is used to cast the PDMS stamp. The PDMS prepolymer is mixed with a curing agent and poured onto the prepared master. The cured stamp is then peeled from the template and is ready for inking. The finished stamp is about 100 μm to about 1 cm thick and the raised portions of the stamp range from about 1 μm to about 500 μm. In an alternative arrangement, a similar method of microcontact printing is performed on a flexible surface, e.g., a tape or conveyor belt. 
     Stamps are inked with a solution containing an active agent, for example, 3-glycidoxypropyltrimethoxysilane (GOPS). After inking, the active agent solution is transferred to the surface of a structure. Care is taken to not deform the stamp while stamping the microchip. Each inked stamp is used to pattern three microchips before reloading the stamp. The active agent is then deposited on the non-treated areas using CVD 
     In another workflow of patterning an active agent and a passive agent onto a silicon plate, polydimethylsiloxane (PDMS) stamps are made using a UV photolithography process. Two silicon wafers coated with photoresist are exposed to UV light through complementary masks, creating complementary patterns on each silicon wafer. The exposed wafers are then exposed to a solution of developer creating a master which is used to cast the PDMS stamps. The PDMS prepolymer is mixed with a curing agent and poured onto the prepared masters. The cured stamps are then peeled from the template and are ready for inking. The finished stamp is about 100 μm to about 1 cm thick and the raised portions of the stamp range from about 1 μm to about 500 μm. 
     The first stamp is inked with a solution containing an active agent, such as 3-glycidoxypropyltrimethoxysilane (GOPS). After inking, the active agent solution is transferred to a silicon plate. The second stamp is inked with a solution containing a passive agent, such as tridecafluoro-1,1,2,2-tetrahydrooctyl)trichlorosilane. After inking, the passive agent solution is transferred to a silicon plate that has been printed with the active agent. Care is taken to not deform the stamps while stamping the microchip. Each inked stamp is used to pattern three microchips before reloading the stamp. In an alternative arrangement, a similar method of microcontact printing is performed on a flexible surface, e.g., a tape or conveyor belt. 
     Structural and Materials 
     Methods for controlled chemical surface patterning described herein may be applied to a variety of structures. In some instances, the structure is about the size of a standard 96 well plate, for example between about 100 and 200 mm by between about 50 and 150 mm. In some instances, a substrate has a diameter less than or equal to about 1000 mm, 500 mm, 450 mm, 400 mm, 300 mm, 250 nm, 200 mm, 150 mm, 100 mm or 50 mm. In some instances, the diameter of a structure is between about 25 mm and 1000 mm, between about 25 mm and about 800 mm, between about 25 mm and about 600 mm, between about 25 mm and about 500 mm, between about 25 mm and about 400 mm, between about 25 mm and about 300 mm, or between about 25 mm and about 200. Non-limiting examples of structure size include about 300 mm, 200 mm, 150 mm, 130 mm, 100 mm, 76 mm, 51 mm and 25 mm. In some instances, a substrate has a planar surface area of at least about 100 mm 2 ; 200 mm 2 ; 500 mm 2 ; 1,000 mm 2 ; 2,000 mm 2 ; 5,000 mm 2 ; 10,000 mm 2 ; 12,000 mm 2 ; 15,000 mm 2 ; 20,000 mm 2 ; 30,000 mm 2 ; 40,000 mm 2 ; 50,000 mm 2  or more. In some cases, the structure is at least about 0.1, 0.2, 0.3, 0.4, 0.5, 1, 2, 3, 4, 6, 8, 10, 16, 24, 39, 50, 100 or more feet in length in a first dimension, and at least about 0.1, 0.2, 0.3, 0.4, 0.5, 1, 2, 3, 4, 6, 8, 10, 16, 24, 39, 50, 100 or more feet in length in a second dimension. For larger structures, a material such as glass, metal or plastic may be used. In some instances, the structure for chemical surface patterning is a flexible material, such as a tape or belt. 
     In some instances, the thickness of a structure is between about 50 mm and about 2000 mm, between about 50 mm and about 1000 mm, between about 100 mm and about 1000 mm, between about 200 mm and about 1000 mm, or between about 250 mm and about 1000 mm. Non-limiting examples of structure thickness include about 0.1 mm, 0.2, 0.3 mm, 0.4 mm, 0.5 mm, 1 mm, 5 mm, 10 mm, 50 mm, 100 mm, 200 mm, 250 mm, 275 mm, 375 mm, 525 mm, 625 mm, 675 mm, 725 mm, 775 mm and 925 mm. In some cases, the thickness of a substrate varies with diameter and depends on the composition of the substrate. For example, a structure comprising materials other than silicon may have a different thickness than a silicon substrate of the same diameter. Structure thickness may be determined by the mechanical strength of the material used and the substrate must be thick enough to support its own weight without cracking during handling. 
     In some instances, a structure described herein comprises a plurality of smaller regions, for example, at least about 2, 4, 6, 8, 10, 16, 24, 39, 50, 100, 200, 250, 500, 1000, 5000, 6000, 7500, 9000, 10000, 20000, 30000, 50000, 100000, 500000, 1000000, or more regions, wherein each region may be used independently from another region. In some cases, regions of a structure are sub-fields or chips of a substrate. In some instances, reference to a substrate includes a region of a substrate. 
     Surfaces for patterning on a structure described herein using methods and systems described herein are fabricated from any material suitable for downstream applications of a patterned surface. As an example, a surface comprises a material resistant to chemicals and/or heat applied to the surface during a chemical reaction, for instance, an oligonucleic acid synthesis reaction. In some instances, a surface comprises a material transparent to visible and/or UV light. In some instances, a surface comprises a conductive material. In some instances, a surface comprises a flexible and/or rigid material. A rigid material includes, without limitation, glass; fused silica; silicon such as silicon dioxide or silicon nitride; metals such as gold or platinum; plastics such as polytetrafluoroethylene, polypropylene, polystyrene, polycarbonate, and any combination thereof. A rigid surface can be fabricated from a material selected from the group consisting of silicon, polystyrene, agarose, dextran, cellulosic polymers, polyacrylamides, polydimethylsiloxane (PDMS), and glass. The substrates/solid supports or the microstructures, reactors therein may be manufactured with a combination of materials listed herein or any other suitable material known in the art. 
     The term “flexible” is used herein to refer to a structure that is capable of being bent, folded or similarly manipulated without breakage. In some cases, a flexible surface is bent at least 30 degrees around a roller. In some cases, a flexible surface is bent at least 180 degrees around a roller. In some cases, a flexible surface is bent at least 270 degrees around a roller. In some instances, a flexible surface is bent about 360 degrees around a roller. In some cases, the roller is less than about 10 cm, 5 cm, 3 cm, 2 cm or 1 cm in radius. In some instances, the flexible surface is bent and straightened repeatedly in either direction at least 100 times without failure (for example, cracking) or deformation at 20° C. In some instances, a flexible surface described herein has a thickness that is amenable to rolling. In some cases, the thickness of the flexible surface described herein is less than about 50 mm, 10 mm, 1 mm, or 0.5 mm. 
     Exemplary flexible materials include, without limitation, nylon (unmodified nylon, modified nylon, clear nylon), nitrocellulose, polypropylene, polycarbonate, polyethylene, polyurethane, polystyrene, acetal, acrylic, acrylonitrile, butadiene styrene (ABS), polyester films such as polyethylene terephthalate, polymethyl methacrylate or other acrylics, polyvinyl chloride or other vinyl resin, transparent PVC foil, transparent foil for printers, Poly(methyl methacrylate) (PMMA), methacrylate copolymers, styrenic polymers, high refractive index polymers, fluorine-containing polymers, polyethersulfone, polyimides containing an alicyclic structure, rubber, fabric, metal foils, and any combination thereof. Nylon and PMAA surfaces herein, in some instances, are provided as a sheet or alternatively provided as a layer that is coated over another material, such as silicon. Various plasticizers and modifiers may be used with polymeric substrate materials to achieve selected flexibility characteristics. 
     Surfaces described herein may comprise a plurality of loci, discrete predetermined locations for oligonucleic acid extension. In some instances, a locus of a surface physically defines an area of the surface as a region for functionalization. In some instances, a functionalized region of a surface defines a locus of the surface. For example, regions of a surface bound with an active functionalization agent are loci of the surface. In some instances, a surface described herein comprises a plurality of clusters, wherein each cluster optionally comprises a plurality of loci. In some instances, a surface comprises a plurality of three-dimensional raised and/or lowered features, wherein a raised and/or lowered feature optionally corresponds to a cluster and/or a locus. A three-dimension feature includes, without limitation, a well, nanowell, channel, and post. In some instances, a three-dimensional feature corresponds to a cluster, wherein the three-dimensional feature optionally comprises a plurality of loci. In some instances, a surface comprises a plurality of channels corresponding to a plurality of loci within a well. 
     In some cases, a surface described herein is patterned by binding a functionalization agent of a set of molecules to one or more defined regions of the surface. In some cases, the surface is differentially functionalized by binding a functionalization agent of a different set of molecules to one or more regions outside of the defined regions. In some instances, an active functionalization agent is bound to and/or defines a feature of a surface, wherein the active agent is chemically reactive with a biomolecule. In some cases, the biomolecule is a nucleic acid monomer and the actively functionalized area supports nucleic acid monomer attachment and synthesis. In some cases, the reactive agent is an adhesion promoter that binds to both surface and functionalization agent. In some instances, a surface comprises a layer of a reactive agent at a thickness of at least or at least about 0.1 nm, 0.5 nm, 1 nm, 2 nm, 5 nm, 10 nm, or 25 nm. In some instances, an adhesion promoter is a chemical with a high surface energy. In some instances, a surface comprises a surface having a high surface energy and a surface having a low surface energy at different regions or features of the surface. In such instances, the proximity of features and/or area of fluid contact at a feature is controlled by the patterning arrangement of the high and low energy regions. 
     In some instances, a surface is functionalized by binding a functionalization agent to a reactive agent of a surface. In some instances, a surface is differentially functionalized by binding different functionalization agents to different areas of a surface. Differential functionalization refers to a process that produces two or more distinct areas on a surface, wherein at least one area has a different surface or chemical property than another area of the same surface. Such properties include, without limitation, surface energy, chemical termination, hydrophilicity, hydrophobicity, and surface concentration of a chemical moiety. 
     Surface functionalization is achieved by any suitable process that results in a change in a chemical property of a surface. In some instances, functionalization comprises application (e.g., deposition) of a functionalization agent to a surface, where the functionalization agent binds to a functional group on the surface. Typically, this results in the deposition of a self-assembled monolayer (SAM) of the functionalization agent. In some instances, a functionalization agent is bound to a structure at a thickness greater than about 0.5 nm, 1 nm, 2 nm, 3 nm, 5 nm, 10 nm, 20 nm, or 50 nm. In some instances, functionalization comprises deposition of a functionalization agent to a structure by any deposition technique, including, but not limiting to, chemical vapor deposition (CVD), atomic layer deposition (ALD), plasma enhanced CVD (PECVD), plasma enhanced ALD (PEALD), metal organic CVD (MOCVD), hot wire CVD (HWCVD), initiated CVD (iCVD), modified CVD (MCVD), vapor axial deposition (VAD), outside vapor deposition (OVD), physical vapor deposition (e.g., sputter deposition, evaporative deposition), and molecular layer deposition (MLD). 
     In some instances, a surface is functionalized at a region to be more hydrophilic or hydrophobic as compared to the region prior to functionalization or as compared to other regions of the surface. In some cases, a surface is modified to have a difference in water contact angle of greater than 90°, 85°, 80°, 75°, 70°, 65°, 60°, 55°, 50°, 45°, 40°, 35°, 30°, 25°, 20°, 15° or 10° as measured on one or more uncurved, smooth or planar equivalent surfaces. In some cases, a three-dimensional feature is modified to have a differential hydrophobicity corresponding to a difference in water contact angle that is greater than 90°, 85°, 80°, 75°, 70°, 65°, 60°, 55°, 50°, 45°, 40°, 35°, 30°, 25°, 20°, 15° or 10° as measured on uncurved, smooth or planar equivalent surfaces. Unless otherwise stated, water contact angles mentioned herein correspond to measurements performed on uncurved, smooth or planar equivalents of the surfaces in question. In some instances, a surface is differentially functionalized with a hydrophilic region and a hydrophobic region. In some cases, a hydrophilic surface is functionalized with a pattern of a hydrophobic agent. In some cases, a hydrophobic surface is functionalized with a pattern of a hydrophilic agent. 
     In some instances, a surface is prepared for functionalization by cleaning it to remove particulates that could interfere with surface binding to a functionalization agent. Surface cleaning includes wet and/or dry processes. In some instances, a surface is wet cleaned with a piranha solution (90% H 2 SO 4 , 10% H 2 O 2 ) at an elevated temperature (e.g., 120° C.). The surface is then washed with a suitable solvent such as water, and dried (e.g., nitrogen gas). A post piranha treatment is optional, which comprises soaking the piranha treated surface in a basic solution (e.g., NH 4 OH) followed by an aqueous wash (e.g., water). In some instances, a surface is plasma cleaned, optionally following a piranha wash and optional post piranha treatment. An example of a plasma cleaning process comprises an oxygen plasma etch. 
     In some instances, a surface is functionalized with an active and/or passive agent. Active functionalization of a surface involves deposition of an active functionalization agent, or active agent, to the surface, where the agent binds to a functional group of the surface. Passive functionalization of a surface involves deposition of a passive functionalization agent, or passive agent, to the surface, where the agent binds to a functional group of the surface. In some instances, an active functionalization agent binds to a reactive group on a surface and comprises a functional group that is reactive with a specific biomolecule, thereby supporting a coupling reaction to the surface. In some cases, an active functionalization agent comprises a carboxyl, thiol, or hydroxyl functional group capable of binding to a nucleoside in a coupling reaction. In some instances, a passive agent is bound at a region of a surface having high surface energy. In some instances, a passive functionalization agent binds to a reactive group on a surface, but lacks an available functional group to bind to a specific biomolecule. In cases wherein the biomolecule is a nucleoside, a passive agent does not efficiently bind to a nucleoside, thereby preventing nucleic acid attachment and synthesis. In some instances, both active and passive functionalization agents are mixed and bound to a particular region of a surface. Such a mixture provides a diluted region of active functionalization agent and therefore lowers the density of any biomolecules bound to the active agent at that particular region. In some instances, functionalization of certain surfaces, such as nylon and PMMA, allows for a one step process, which eliminates the need for deposition of a layer of active agent. 
     In some instances, functionalization of a surface comprises deposition of a functionalization agent to the surface, where the agent self-assembles as a layer on the surface. Non-limiting examples of self-assembly agents include n-octadecyltrichlorosilane, 11-bromo undecyltrichlorosilane, 1H,1H,2H,2H-perfluoro-decyltrichlorosilane, N-[3-(trimethoxysilyl)propyl]-ethylenediamine, (3-aminopropyl)trimethoxy-silane, (3-aminopropyl)triethoxysilane, (3-mercaptpropyl)trimethoxysilane, PEG silanes (having a trichlorosiloxane, trimethoxysiloxane, or triethoxysiloxane functional group), N-(6-aminohexyl)-3-aminopropyltrimethoxysilane, phenyltrichlorosilane, benzyltrichlorosilane, n-octadecyltrimethoxysilane, heptadecafluoro-1,1,2,2-tetrahydro-decyl-1-trimethoxy-silane, 3,3,3-trifluoropropyltrimethoxysilane, (4-chloromethyl)phenyltrimethoxysilane, 18-nonadecenyltrichlorosilane, and 2,2,2-trifluoroethyl undec-10-enoate. 
     In some instances, an active functionalization agent comprises a silane group that binds to a surface of a structure, while the rest of the molecule provides a distance from the surface and a free hydroxyl group at the end to which a biomolecule attaches. Non-limiting examples of silanes include N-(3-triethoxysilylpropyl)-4-hydroxybutyramide (HAPS), 11-acetoxyundecyltriethoxysilane, n-decyltriethoxysilane, (3-aminopropyl)trimethoxysilane, (3-aminopropyl)triethoxysilane, 3-glycidoxypropyltrimethoxysilane (GOPS), 3-iodo-propyltrimethoxysilane. In some instances, a silane is an amino silane. In some instances, a silane is an organofunctional alkoxysilane molecule. Non-limiting examples of organofunctional alkoxysilane molecules include butyl-aldehydr-trimethoxysilane; dimeric secondary aminoalkyl siloxanes; aminosilanes such as (3-aminopropyl)-triethoxysilane, (3-aminopropyl)-diethoxy-methylsilane, (3-aminopropyl)-dimethyl-ethoxysilane, and (3-aminopropyl)-trimethoxysilane; glycidoxysilanes such as (3-glycidoxypropyl)-dimethyl-ethoxysilane and glycidoxy-trimethoxysilane; and mercaptosilanes such as (3-mercaptopropyl)-trimethoxysilane, 3-4 epoxycyclohexyl-ethyltrimethoxysilane and (3-mercaptopropyl)-methyl-dimethoxysilane. Organofunctional silanes include siloxanes such as hydroxyalkyl siloxanes, including allyl trichlorochlorosilane as a precursor for 3-hydroxypropyl and 7-oct-1-enyl trichlorochlorosilane as a precursor for 8-hydroxyoctyl; diol (dihydroxyalkyl) siloxanes including glycidyl trimethoxysilane-derived (2,3-dihydroxypropyloxy)propyl (GOPS); aminoalkyl siloxanes, including 3-aminopropyl trimethoxysilane; and dimeric secondary aminoalkyl siloxanes, including bis (3-trimethoxysilylpropyl) amine as a precursor for bis(silyloxylpropyl)amine. 
     In some instances, a passive functionalization agent comprises a silane group, for example, perfluorooctyltrichlorosilane, (tridecafluoro-1,1,2,2-tetrahydrooctyl)trichlorosilane, or tridecafluoro-1,1,2,2-tetrahydrooctyl)trimethoxysilane. In some instances, a passive functionalization agent comprises perfluorooctyltriethoxysilane. In some instances, a passive functionalization agent comprises perfluorooctyltrimethoxysilane. In some instances, a passive functionalization agent comprises a hydrocarbon silane, such as octadecyltrichlorosilane or similar. In some instances, a passive functionalization agent comprises a fluorosilane. In some cases, a passive functionalization agent comprises a mixture of a hydrocarbon silane and a fluorosilane. Non-limiting examples of fluorosilanes include 1H, 1H, 2H, 2H-fluorooctyltriethoxysilane (FOS), trichloro(1H, 1H, 2H, 2H-perfluorooctyl)silane, tert-Buty-[5-fluoro-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)indol-1-yl]-dimethyl-silane, CYTOP™, Fluorinert™, and precursors perfluoroctyltrichlorosilane (PFOTCS), perfluorooctyldimethylchlorosilane (PFODCS), perfluorodecyltriethoxysilane (PFDTES), and pentafluorophenyl-dimethylpropylchloro-silane (PFPTES). In some instances, a passive functionalization agent comprises an organofunctional alkoxysilane molecule. Non-limiting examples of an organofunctional alkoxysilane molecule include dimethylchloro-octodecyl-silane; methyldichloro-octodecyl-silane; trichloro-octodecyl-silane; trimethyl-octodecyl-silane; and triethyl-octodecyl-silane. 
     In some instances, surface functionalization molecules described herein include a cross-linking agent to allow for the coupling f two different molecular entities. Exemplary cross-linking agents include, N-hydroxysuccinimide esters (NHS esters) which react with primary amines to yield stable amide bonds, sulfo-NHS esters (which additionally contain a sulfonate (—SO3) group on the N-hydroxysuccinimide ring), imidoesters, and sulfhydryl reactive cross linkers (e.g., maleimides, haloacetyls, and pyridyl disulfides). 
     Surface described herein are, in some instances, patterned with a mixture of agents. In some instances, a mixture comprises at least 2, 3, 4, 5 or more different types of functionalization agents. In some cases, the ratio of the at least two types of surface functionalization agents in a mixture is about 1:1, 1:2, 1:5, 1:9, 1:10, 2:10, 3:10, 4:10, 5:10, 6:10, 7:10, 8:10, 9:10, 5:95, 1:100, 1:150, 1:200, or any other ratio to achieve a desired surface representation of two groups. In some instances, desired surface tensions, wettabilities, water contact angles, and/or contact angles for other suitable solvents are achieved by providing a surface with a suitable ratio of functionalization agents. In some instances, the agents in a mixture are chosen from suitable reactive and inert moieties, thus diluting the surface density of reactive groups to a desired level for downstream reactions. In some instances, the mixture of functionalization reagents comprises one or more reagents that bind to a biomolecule and one or more reagents that do not bind to a biomolecule. Therefore, modulation of the reagents allows for the control of the amount of biomolecule binding that occurs at a distinct area of functionalization. 
     In some instances, a surface is functionalized with a set of molecules comprising a mixture of silanes, under reaction conditions effective to couple the silanes to the surface, typically via reactive hydrophilic moieties present on the surface. In some instances, active functionalization areas comprise one or more different species of silanes, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 or more silanes. In some cases, one of the one or more silanes is present in the functionalization composition in an amount greater than another silane. For example, a mixed silane solution having two silanes comprises a 99:1, 98:2, 97:3, 96:4, 95:5, 94:6, 93:7, 92:8, 91:9, 90:10, 89:11, 88:12, 87:13, 86:14, 85:15, 84:16, 83:17, 82:18, 81:19, 80:20, 75:25, 70:30, 65:35, 60:40, 55:45 ratio of one silane to another silane. In some instances, an active functionalization agent comprises 11-acetoxyundecyltriethoxysilane and n-decyltriethoxysilane. In some instances, an active functionalization agent comprises 11-acetoxyundecyltriethoxysilane and n-decyltriethoxysilane in a ratio from about 20:80 to about 1:99, or about 10:90 to about 2:98, or about 5:95. 
     In some instances, a functionalization agent is modified with a protecting group that protects the agent during a process step of a functionalization method. For example, an active agent is bound to a surface, where an oligonucleic acid platform is grown. The oligonucleic acids of the platform are protected with a trityl protecting group, rendering the oligonucleic acids unreactive during subsequent patterning process steps. The protecting group is then removed, or deprotected, to allow for continued oligonucleic acid synthesis. Exemplary protecting groups include, without limitation, acetyl, benzoyl, benzyl, β-methoxyethoxymethyl ether, dimethoxytrityl, [bis-(4-methoxyphenyl)phenylmethyl], methoxymethyl ether, methoxytrityl [(4-methoxyphenyl)diphenylmethyl, p-methoxybenzyl ether, methylthiomethyl ether, pivaloyl, tetrahydropyranyl (removed by acid), tetrahydrofuran, trityl (triphenylmethyl, removed by acid and hydrogenolysis), silyl ether (trimethylsilyl, tert-butyldimethylsilyl, tri-iso-propylsilyloxymethyl, and triisopropylsilyl ethers, methyl ethers, and ethoxyethyl ethers. Exemplary agents for removing such protecting groups are known by one of skill in the art. 
     In some instances, a surface described herein comprises a plurality of clusters, wells, or clusters and wells, wherein a well optionally corresponds to one or more clusters. In some instances, the diameter or width of a cluster is from about 0.05 mm to about 10 mm, from about 0.1 mm to about 10 mm, from about 0.5 mm to about 10 mm, from about 0.5 mm to about 5 mm, from about 0.5 mm to about 2 mm, from about 0.8 mm to about 2 mm, from about 1 mm to about 2 mm, from about 1 mm to about 1.5 mm, or from about 0.8 mm to about 1.5 mm. In some instances, the diameter of a cluster and/or well is about 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.15, 1.2, 1.3., 1.4, 1.5, 1.6, 1.7, 1.8, or 2.0 mm. In some instances, the diameter or width of a cluster is less than or about 5 mm, 2, 1.5, 1 mm, 0.5 mm, 0.1 mm, or 0.05 mm. In some instances, a surface comprises a three-dimensional feature, such as a well or post, having a height from about 20 um to about 1,000 um; from about 100 um to about 1,000 um; or from about 500 um to about 1,000 um. In some cases, the height of a three-dimensional feature is less than about 1,000 um; less than about 800 um; or less than about 600 um. In some instances, the cluster is within a well. In some instances, a surface comprises a textured surface. Exemplary textured surfaces include an array of recesses (e.g., wells) or protrusions (e.g., posts) having a height or depth from the surface of about 1 to about 1000 nm, about 250 to about 1000 nm, about 250 to about 750 nm, or about 100 to about 500 nm. In some instances, each feature of the textures surface has a pitch that is about 0.5 to about 5 times the distance of the height or depth from the surface. In some instances, each feature of the textures surface has a pitch that is about 0.5 times to about twice the distance of the height or depth from the surface. 
     In some instances, a surface comprises a plurality of loci. The loci may correspond to defined planar areas on the surface (e.g., a circle or square), channels, or microwells. In some cases, the height or depth of a channel and/or microwell is from about 5 um to about 500 um, from about 5 um to about 200 um, from about 5 um to about 50 um, or from about 10 um to about 50 um. In some cases, the height of a channel and/or microwell is less than 100 um, less than 50 um, less than 30 um or less than 20 um. In some instances, the height or depth of a channel and/or microwell is about 1, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 or more um. In some instances, the width of a locus, channel, and/or microwell is from about 1 um to about 1000 um, or about 0.1 um to about 500 um. In some instances, the width of a locus, channel, and/or microwell from about 0.5 um to about 500 um, from about 3 um to about 60 um, or from about 1 um to about 100 um. In some instances, the width of a locus is about 100 um, 80 um, 60 um, 40 um, 20 um, 10 um, 5 um, 1 um, or 0.5 um. In some instances, the width of a locus is about 0.5 to about 60 um. In some instances, the width of a locus is about 0.5 to about 20 um. In some instances, the diameter of a locus is about 0.5 to about 10 um. In some instances, the width of a locus is about 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, or 40 um. In some instances, the width of a locus, channel, and/or microwell is less than about 100 um, 80 um, 50 um, 20 um or 10 um, or 1 um. In some instances, the distance between the center of two adjacent loci, channels, and/or microwells is from about 0.1 um to about 50 um, from about 0.1 um to about 10 um, from about 1 um to about 500 um, from about 1 um to about 100 um, or from about 5 um to about 50 um, for example, about 20 um. In some instances, the width of a locus, channel, and/or microwell is about 10 urn, 20 urn, 30 urn, 40 um, 50 um, 60 um, 70 um, 80 um, 90 um, or 100 um. Loci described herein may be in a shape that includes, without limitation, circles, squares, rectangles, ovals, and triangles. The term “microwell” as used herein refers to a feature that holds a liquid. The predetermined regions which are exposed to a light source form areas defining a locus for nucleic acid extension. In some instances, the predetermined regions for nucleic acid extension have a perimeter that is, without limitation, a circle, oval, rectangle, a rectangle in shape. 
     The microchannels or microwells can have an aspect ratio of less than 1. As used herein, the term “aspect ratio,” refers to the ratio of a channel&#39;s width to that channel&#39;s depth. Thus, a channel having an aspect ratio of less than 1, is deeper than it is wide, while a channel having an aspect ratio greater than 1 is wider than it is deep. In some aspects, the aspect ratio of the microchannels or microwells can be less than or equal to about 0.5, about 0.2, about 0.1, about 0.05 or less. In some instances, the aspect ratio of the microchannels or microwells can be about 0.1. In some instances, the aspect ratio of the microchannels or channels can be about 0.05. The microstructures described herein, e.g., microchannels or microwells having aspect ratios less than 1, 0.1 or 0.05, may include channels having one, two, three, four, five, six or more corners, turns, and the like. The microstructures described herein may include the aspect ratios described, e.g., less than 1, 0.1 or 0.05, with respect to all microchannels or microwells contained within a particular resolved locus, e.g., one or more intersecting channels, some of these channels, a single channel and even a portion or portions of one or more microchannels or microwells. In some instances the wells have an aspect ratio of about 1:1 to 1:15. In some instances the wells have an aspect ratio of about 1:10. In some instances the microchannels have an aspect ratio of about 1:1 to 1:15. In some instances the microchannels have an aspect ratio of about 1:10. 
     In some instances, a surface comprises more than about 500; 2,000; 20,000; 100,000; 4000,000; 500,000; 8,000,000; 1,000,000; 3,000,000; 5,000,000; or 10,000,000 features. In some cases, a surface comprises features at a density of at least about 1, 5, 10, 20, 50, 100, 150, 200, 300, 400 or 500 features per mm 2 . In some instances, a surface comprises at least about 10; 500; 1,000; 5,000; 6,000; 8,000; 10,000; 15,000; 20,000; 30,000; 50,000 or more clusters. In some cases, a cluster comprises from about 1 to about 10,000 loci. In some instances, a surface comprises more than about 500; 2,000; 20,000; 100,000; 4000,000; 500,000; 8,000,000; 1,000,000; 3,000,000; 5,000,000; or 10,000,000 loci. 
     In various aspects, a surface comprises one or more clusters, wherein a cluster comprises a plurality of loci. In some instances, the density of loci within a cluster of a surface is at least or about 1 locus per mm 2 , 10 loci per mm 2 , 100 loci per mm 2 , 500 loci per mm 2 , 1,000 loci per mm 2  or more. In some cases, a surface comprises from about 10 loci per mm 2  to about 500 mm 2  or from about 50 loci per mm 2  to about 200 mm 2 . In some instances, the distance between the centers of two adjacent loci within a cluster is from about 10 um to about 500 um, from about 10 um to about 200 um, or from about 10 um to about 100 um. In some cases, the distance between the centers of two adjacent loci within a cluster is less than about 200 um, 150 um, 100 um, 50 um, 20 um or 10 um. In some cases, about 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 300, 400, 500 or more loci are located within a single cluster. In some cases, about 50 to about 500 loci are located within a single cluster. In some cases, about 100 to about 150 loci are located within a single cluster. In some cases, about 100, 110, 115, 120, 125, 130, 135, or 140 loci are located within a single cluster. In some cases, about 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 300, 400, 500 or more channels are located within a single well. In some cases, about 50 to about 500 loci are channels are located within a single well. In some cases, about 100 to about 150 loci are channels are located within a single well. In some cases, about 100, 110, 115, 120, 125, 130, 135, or 140 channels are located within a single well. 
     In some instances, the density of clusters within a surface is at least or about 1 cluster per 100 mm 2 , 1 cluster per 10 mm 2 , 1 cluster per 1 mm 2 , 10 clusters per 1 mm 2 , 50 clusters per 1 mm 2  or more. In some instances, a surface comprises from about 1 cluster per 10 mm 2  to about 10 clusters per 1 mm 2 . In some instances, the distance between the centers of two adjacent clusters is less than about 50 um, 100 um, 200 um, 500 um, 1000 um, or 2000 um or 5000 um. In some cases, the distance between the centers of two adjacent clusters is between about 50 um and about 100 um, between about 50 um and about 500 um, or between about 100 um to about 2000 um. 
     In some instances, a structure is about the size of a standard 96 well plate, for example, between about 100 and 200 mm by between about 50 and 150 mm. In some instances, the surface is about 140 mm by about 90 mm. In some instances, structures described herein are e over 1, 2, 5, 10, 30, 50 or more feet long in any dimension. In the case of a flexible structure, the flexible structure is optionally stored in a wound state, e.g., in a reel. In the case of a large rigid structure, e.g., greater than 1 foot in length, the rigid structure can be functionalized and stored while in a vertical or horizontal orientation. 
     In some instances, the surface comprises an array of wells or cluster that are in a 96 by 64 arrangement. In some instances, the pitch is about 1.125 mm in the printing direction. In some instances, a single cluster comprises about 50 to about 500 loci. In some instances, a single cluster comprises about 100 to about 200 loci. In some instances, a single cluster comprises about 100 to about 150 loci. In some instances, a single cluster comprises about 120 to 140 loci. In some instances, a single cluster comprises about 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, or 140 loci. In some instances, a surface comprises at least 500000, 600000, 700000, 800000, 900000, or 1000000 loci. 
     In some instances, a structure comprises a plurality of smaller regions, for example, at least about 2, 4, 6, 8, 10, 16, 24, 39, 50, 100 or more regions, wherein each region is optionally configured for use independent of another region. In some cases, regions of a surface are sub-fields or chips of a structure. In some instances, reference to a surface includes a region of a surface. In some instances, the structure is 140 mm×90 mm. 
     In some instances, a surface has a planar surface area of less than about 100 mm 2 ; 200 mm 2 ; 500 mm 2 ; 1,000 mm 2 ; 5,000 mm 2 ; 10,000 mm 2 ; 20,000 mm 2 ; or 50,000 mm 2 . In some instances, the thickness of a structure is between about 50 mm and about 2000 mm, between about 100 mm and about 1000 mm, or between about 250 mm and about 1000 mm. Non-limiting examples of structure thickness include 275 mm, 375 mm, 525 mm, 625 mm, 675 mm, 725 mm, 775 mm and 925 mm. In some cases, the thickness of a structure varies with diameter and depends on the composition of the structure. In some cases, structure thickness is determined by the mechanical strength of the material used, wherein the structure must be thick enough to support its own weight without cracking during handling. 
     In some instances, a surface comprises a structure to align the surface with a device during surface modification. For example, dicing marks, shadow mask alignment marks, fiducials or a combination thereof. In some instances, a surface is labeled. In some cases, a surface comprises a structure to facilitate alignment with a reagent deposition device. 
     In various aspects, a structure described herein comprises a three-dimensional feature prepared by an etching method. An exemplary etching method comprises: (1) oxidizing a silicon structure on a surface that will be designed with a three-dimensional feature; (2) application of photolithography to the oxidized surface to create a mask of photoresist; (3) etching at locations of the structure devoid of photoresist, in many cases, beyond the oxidized layer, to create a feature; and (4) photoresist is stripping. In some examples, deep reactive-ion etching (DRIE) is used to etch vertical side walls to a prescribed depth to generate a well. In some instances, only one side of a structure is etched to create a three-dimensional feature. In some instances, two sides, e.g., device and handle sides, of a structure is etched to create three-dimensional features. In some processes, as an alternative or supplement to etching by DRIE, a SOI structure (silicon on insulator silicon wafer) is used and the handle layer is etched down to the buried oxide, where the buried oxide serves as an etch stop. Following photolithography on a second side of a structure, the photoresist is stripped to generate a desired three-dimensional pattern. 
     Light Sources 
     Light sources described herein provide EMR for the purpose of creating a functionalized, patterned surface via photolytic cleavage. EMR emitting lamps and lasers are known by those of skill in the art and include commercially available lamps and lasers as well as custom built lamps and lasers that provide DUV light at the various wavelengths. 
     Lamps 
     Lamps described herein include those having various light source arrangements, such as cylindrical lamps, flat lamps emitting light, and flat lamps with a large plane emitting light. In some instances, cylindrical lamps have a variable distance between areas of the lamp surface and the chip surface, which in some instances, results in decreased uniformity of the DUV exposure to the chip. Cylindrical lamps disclosed herein may be mounted in a rectangular shiny (reflective) housing. In some instances, lamps disclosed herein include excimer lamps. Lamps disclosed herein emit a DUV light at wavelengths including but not limited to 126 nm, 152 nm, and 172 nm. In some instances lamps herein emit a DUV light at 172 nm. 
     In some instances, lamps disclosed herein comprise flat light emitting panel portion that provides an even exposure of DUV light to the target surface. In some instances, even exposure of DUV provides for a more uniform surface exposure over the chip than lamps that are not flat. In some instances, lamps disclosed herein comprise flat lamps capable of providing DUV exposure to a larger work surface, providing for larger chips or a greater number of chips to be processed simultaneously. For example, the lamp may comprise a flat light emitting surface that is 6 inches×6 inches or more. In some instances, the flat light emitting surface has a surface areas of at least 4, 16, 36, 64, 144, or more inches squared. 
     Lasers 
     Lasers described herein provide ERM via a process of optical amplification providing light having a focused light emission, allowing precise application of EMR to the functionalized surface. Useful wavelengths for lasers herein include but are not limited to 152 nm, 172 nm, and 193 nm. Exemplary lasers and their wavelengths include but are not limited to Ar 2  (126 nm), Kr 2  (146 nm), F 2  (157 nm), Xe 2  (172 and 175 nm), ArF (193 nm). Lasers used in methods described herein include excimer lasers and liquid immersion techniques. Excimer lasers herein include an F 2  excimer laser having a wavelength of 157 nm. In some instances, excimer lasers provide higher resolution, which is beneficial to certain applications. Liquid immersion techniques, also termed immersion lithography, enables use of optics with numerical apertures exceeding 1.0, and uses a liquid, such as ultra-pure, deionized water, to provide a refractive index above that of air. 
     Systems 
     Provided herein, in some instances, are systems for performing a surface functionalization method as described herein. In some instances, a surface functionalization system comprises a deposition device for application of one or more reagents to a surface. In some instances, a surface functionalization system comprises a device for treating a surface with a fluid, for example, a flow cell. In some instances, surface functionalization system comprises a device for moving a surface between a deposition device and a treatment device. In some instances, a surface functionalization system comprises a cleavage device comprising a source of EMR for cleaving a chemical bond at a surface and a shadow mask for positioning between the EMR source and a surface. 
     In some instances, surface functionalization methods described herein employ a system comprising a deposition device that deposits reagents necessary for surface functionalization. For example, active agents, passive agents, and/or wash solutions. In some instances, wherein a functionalized surface product provides a surface for oligonucleic acid synthesis, a deposition device deposits synthesis reagents. In some instances, a deposition device moves in the X-Y direction to align with a location of a surface and optionally moves in the Z direction to seal with a surface, forming a resolved reactor. 
     In some instances, a deposition device comprises a plurality of deposition heads, for example, from about 1 to about 50 deposition heads. In some instances, a deposition head deposits a reagent component that is different from another reagent deposited by another deposition head. In some cases, a deposition head comprises a plurality of nozzles, wherein each nozzle is optionally configured to correspond to a cluster on a surface. For example, for a surface having 256 clusters, a deposition head comprises 256 nozzles. In some cases, a nozzle deposits a reagent component that is different from another nozzle. 
     Further provided herein is an automated system for use with a functionalization method described herein that is capable of functionalizing one or more surfaces, comprising: a deposition device for spraying a microdroplet comprising a functionalization agent on a surface; a scanning transport for scanning the surface adjacent to the deposition device to selectively deposit the microdroplet at specified sites; a flow cell for treating the surface on which the microdroplet is deposited by exposing the surface to one or more selected fluids; a cleavage device comprising a source of EMR for cleaving a chemical bond at a surface and a shadow mask for positioning between the EMR source and a surface; and an alignment unit for aligning the surface correctly relative to the deposition device and cleavage device. In some instances, the source of EMR comprises a laser which does not require use of a shadow mask. In some instances, the system optionally comprises a treating transport for moving the surface between the deposition device and the flow cell for treatment in the flow cell, where the treating transport and said scanning transport are different elements. In other instances, the system does not comprise a treating transport. 
     In some instances, a deposition device deposits a functionalization agent onto a surface of a structure. In some instances, a deposition device deposits a functionalization agent to a resolved cluster, locus, well, post, and/or channel of a surface. In some cases, a deposition device deposits a drop having a diameter less than about 200 um, 100 um, or 50 um in a volume less than about 1000, 500, 100, 50, 40 or 20 pl. In some cases, a deposition device deposits between about 1 and 10000, 1 and 5000, 100 and 5000, or 1000 and 5000 droplets per second. 
     In some instances, during a functionalization method, a surface is positioned within or sealed within a flow cell. In some instances, a flow cell provides continuous or discontinuous flow of liquids such as those comprising reagents necessary for reactions within the surface, for example, wash solutions. In some instances, a flow cell provides continuous or discontinuous flow of a gas, such as nitrogen, for drying a surface typically through enhanced evaporation of a volatile substance. A variety of auxiliary devices are useful to improve drying and reduce residual moisture on a surface. Examples of such auxiliary drying devices include, without limitation, a vacuum source, depressurizing pump and a vacuum tank. In some cases, a surface functionalization system comprises one or more flow cells, such as 2, 3, 4, 5, 6, 7, 8, 9, 10, or 20 and one or more surfaces, such as 2, 3, 4, 5, 6, 7, 8, 9, 10 or 20. In some cases, a flow cell is configured to hold and provide reagents to a surface during one or more steps in a functionalization reaction. In some instances, a flowcell comprises a lid that slides over the top of a surface and is clamped into place to form a pressure tight seal around the edge of the surface. An adequate seal includes, without limitation, a seal that allows for about 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 atmospheres of pressure. In some cases, a flow cell lid is opened to allow for access to an application device such as a deposition device. In some cases, one or more steps of surface functionalization method are performed on a surface within a flow cell, without the transport of the surface. 
     In some instances, a surface functionalization system comprises one or more elements useful for downstream application of a functionalized surface. As an example, wherein a functionalized surface is prepared for oligonucleic acid synthesis support, a deposition device is configured to deposit oligonucleic acid reagents such as, nucleobases and coupling reagents. 
     Gene Synthesis 
     Provided herein are differentially functionalized surfaces configured to support the attachment and synthesis of oligonucleic acids. An example workflow is shown in  FIG. 8 . The workflow is divided generally into the following processes: (1) de novo synthesis of a single stranded oligonucleic acid library, (2) joining oligonucleic acids to form larger fragments, (3) error correction, (4) quality control, and (5) shipment. Prior to de novo synthesis, an intended nucleic acid sequence or group of nucleic acid sequences is preselected. For example, a group of genes is preselected for generation. 
     In an example workflow, a structure comprising a surface layer  801  is provided ( FIG. 8 ). In the example, chemistry of the surface is functionalized in order to improve the oligonucleic acid synthesis process. The surface itself may be in the form of a planar surface or contain variations in shape, such as protrusions or nanowells which increase surface area. In the workflow example, high surface energy molecules selected support oligonucleic acid attachment and synthesis. 
     In first step of the workflow example, a device, such as an oligonucleic acid synthesizer, is designed to release reagents in a step wise fashion such that multiple oligonucleic acids extend from an actively functionalized surface region, in parallel, one residue at a time to generate oligomers with a predetermined nucleic acid sequence. In some cases, oligonucleic acids are cleaved from the surface at this stage. Cleavage includes gas cleavage, e.g., with ammonia or methylamine. 
     The generated oligonucleic acid libraries are placed in a reaction chamber. In this exemplary workflow, the reaction chamber (also referred to as “nanoreactor”) is a silicon coated well containing PCR reagents lowered onto the oligonucleic acid library  803 . Prior to or after the sealing  804  of the oligonucleic acids, a reagent is added to release the oligonucleic acids from the surface. In the exemplary workflow, the oligonucleic acids are released subsequent to sealing of the nanoreactor  805 . Once released, fragments of single-stranded oligonucleic acids hybridize in order to span an entire long range sequence of DNA. Partial hybridization  805  is possible because each synthesized oligonucleic acid is designed to have a small portion overlapping with at least one other oligonucleic acid in the pool. 
     After hybridization, oligonucleic acids are assembled in a PCA reaction. During the polymerase cycles of the PCA reaction, the oligonucleic acids anneal to complementary fragments and gaps are filled in by a polymerase. Each cycle increases the length of various fragments randomly depending on which oligonucleic acids find each other. Complementarity amongst the fragments allows for forming a complete large span of double-stranded DNA  806 . 
     After PCA is complete, the nanoreactor is separated from the surface  807  and positioned for interaction with a surface having primers for PCR  808 . After sealing, the nanoreactor is subject to PCR  809  and the larger nucleic acids are amplified. After PCR  810 , the nanochamber is opened  811 , error correction reagents are added  812 , the chamber is sealed  813  and an error correction reaction occurs to remove mismatched base pairs and/or strands with poor complementarity from the double-stranded PCR amplification products  814 . The nanoreactor is opened and separated  815 . Error corrected product is next subject to additional processing steps, such as PCR, nucleic acid sorting, and/or molecular bar coding, and then packaged  822  for shipment  823 . 
     In some cases, quality control measures are taken. After error correction, quality control steps include, for example, interaction with a wafer having sequencing primers for amplification of the error corrected product  816 , sealing the wafer to a chamber containing error corrected amplification product  817 , and performing an additional round of amplification  818 . The nanoreactor is opened  819  and the products are pooled  820  and sequenced  821 . In some cases, nucleic acid sorting is performed prior to sequencing. After an acceptable quality control determination is made, the packaged product  822  is approved for shipment  823 . 
     In some instances, polymerase chain reaction (PCR)-based and non-polymerase-cycling-assembly (PCA)-based strategies can be used for chemical gene synthesis. In addition, non-PCA-based chemical gene synthesis using different strategies and methods, including enzymatic gene synthesis, annealing and ligation reaction, simultaneous synthesis of two genes via a hybrid gene, shotgun ligation and co-ligation, insertion gene synthesis, gene synthesis via one strand of DNA, template-directed ligation, ligase chain reaction, microarray-mediated gene synthesis, Blue Heron solid support technology, Sloning building block technology, RNA-mediated gene assembly, the PCR-based thermodynamically balanced inside-out (TBIO), two-step total gene synthesis method that combines dual asymmetrical PCR (DA-PCR), overlap extension PCR, PCR-based two-step DNA synthesis (PTDS), successive PCR method, or any other suitable method known in the art can be used in connection with the methods and compositions described herein, for the assembly of longer polynucleotides from shorter oligonucleotides. 
     In some instances, methods for the synthesis of oligonucleic acids on the surfaces described herein involve an iterative sequence of the following steps: application of a protected monomer to an actively functionalized surface of a surface feature to link with either the surface, a linker or with a previously deprotected monomer; deprotection of the applied monomer so that it can react with a subsequently applied protected monomer; and application of another protected monomer for linking. One or more intermediate steps include oxidation and/or sulfurization. In some cases, one or more wash steps precede or follow one or all of the steps. In particular, a method for oligonucleic acid synthesis on a functionalized surface of this disclosure is a phosphoramidite method comprising the controlled addition of a phosphoramidite building block, i.e. nucleoside phosphoramidite, to a growing oligonucleic acid chain in a coupling step that forms a phosphite triester linkage between the phosphoramidite building block and a nucleoside bound to the surface. In some instances, the nucleoside phosphoramidite is provided to the surface activated or with an activator. In some instances, nucleoside phosphoramidites are provided to the surface in a 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 25, 30, 35, 40, 50, 60, 70, 80, 90, 100-fold excess or more over the surface-bound nucleosides. In some instances, the addition of nucleoside phosphoramidite is performed in an anhydrous environment, for example, in anhydrous acetonitrile. Following addition and linkage of a nucleoside phosphoramidite in the coupling step, the surface is optionally washed. In some instances, the coupling step is repeated one or more additional times, optionally with a wash step between nucleoside phosphoramidite additions to the surface. In some instances, an oligonucleic acid synthesis method used herein comprises 1, 2, 3 or more sequential coupling steps. Prior to coupling, in many cases, the nucleoside bound to the surface is de-protected by removal of a protecting group, where the protecting group functions to prevent polymerization. A common protecting group is 4,4′-dimethoxytrityl (DMT). 
     Following coupling, phosphoramidite oligonucleic acid synthesis methods optionally comprise a capping step. In a capping step, a growing oligonucleic acid is treated with a capping agent. A capping step generally serves to block unreacted surface-bound 5′-OH groups after coupling from further chain elongation, preventing the formation of oligonucleic acids with internal base deletions. In some instances, inclusion of a capping step during oligonucleic acid synthesis decreases the error rate as compared to synthesis without capping. As an example, the capping step comprises treating the surface-bound oligonucleic acid with a mixture of acetic anhydride and 1-methylimidazole. Following a capping step, the surface is optionally washed. 
     In one aspect, systems and methods described herein are configured to synthesize a high density of oligonucleic acids on a substrate with a low error rate. In some cases, these bases are synthesized with a total average error rate of less than about 1 in 100; 200; 300; 400; 500; 1000; 1500; 2000; 5000; 10000; 15000; 20000 bases. In some instances, these error rates are for at least 50%, 60%, 70%, 80%, 90%, 95%, 98%, 99%, 99.5%, or more of the oligonucleic acids synthesized. In some instances, these at least 90%, 95%, 98%, 99%, 99.5%, or more of the oligonucleic acids synthesized do not differ from a predetermined sequence for which they encode. In some instances, the error rate for synthesized oligonucleic acids on a substrate using the methods and systems described herein is less than about 1 in 200. In some instances, the error rate for synthesized oligonucleic acids on a substrate using the methods and systems described herein is less than about 1 in 500. In some instances, the error rate for synthesized oligonucleic acids on a substrate using the methods and systems described herein is less than about 1 in 1,000. In some instances, the error rate for synthesized oligonucleic acids on a substrate using the methods and systems described herein is less than about 1 in 1,500. In some instances, the error rate for synthesized oligonucleic acids on a substrate using the methods and systems described herein is less than about 1 in 2,000. In some instances, the error rate for synthesized oligonucleic acids on a substrate using the methods and systems described herein is less than about 1 in 3,000. In some instances, the error rate for synthesized oligonucleic acids on a substrate using the methods and systems described herein is less than about 1 in 5,000. Individual types of error rates include mismatches, deletions, insertions, and/or substitutions for the oligonucleic acids synthesized on the substrate. The term “error rate” refers to a comparison of the collective amount of synthesized oligonucleic acid to an aggregate of predetermined oligonucleic acid sequences. In some cases, synthesized oligonucleic acids disclosed herein comprise a tether of 12 to 25 bases. In some instances, the tether comprises 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50 or more bases. 
     Oligonucleic acid libraries synthesized by methods described herein may comprise at least about 100, 121, 200, 300, 400, 500, 600, 750, 1000, 5000, 6000, 15000, 20000, 30000, 40000, 50000, 60000, 75000, 100000, 200000, 300000, 400000, 500000, 600000, 700000, 750000, 1000000, 2000000, 3000000, 4000000, 5000000, or more different oligonucleic acids. The different oligonucleic acids or may be related to predetermined/preselected sequences. It is understood that the library may comprise of a plurality of different subsections, such as about 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 24 subsections or more. Compositions and methods of the invention further allow construction of the above mentioned large synthetic libraries of oligonucleic acids with low error rates described above in short time frames, such us in less than three months, two months, one month, three weeks, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2 days or less. In some instances, oligonucleic acid libraries synthesized by methods described herein comprise loci, each having different oligonucleic acids than another loci, wherein each locus has a population at least about 75% uniform when measured by calculating amplitude of signal variation for oligonucleic acids extending from each locus divided by total signal intensity following white light illumination using an optical microscope. 
     Gene libraries synthesized by methods described herein may comprise at least about 50, 100, 200, 250, 300, 400, 500, 600, 750, 1000, 5000, 6000, 15000, 20000, 30000, 40000, 50000, 60000, 75000, 100000, 200000, 300000, 400000, 500000, 600000, 750000, 1000000, 2000000, 3000000, 4000000, 5000000, or more different genes. Compositions and methods of the invention further allow construction of the above mentioned large libraries of genes with low error rates described above in short time frames, such us in less than three months, two months, one month, three weeks, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2 days or less. Genes of the above mentioned libraries may be synthesized by assembling de novo synthesized oligonucleic acids by suitable gene assembly methods further described in detail elsewhere herein or otherwise known in the art. 
     In some instances, following addition of a nucleoside phosphoramidite, and optionally after capping and one or more wash steps, the surface bound growing nucleic acid is oxidized. The oxidation step comprises oxidizing the phosphite triester into a tetracoordinated phosphate triester, a protected precursor of the naturally occurring phosphate diester internucleoside linkage. In some cases, oxidation of the growing oligonucleic acid is achieved by treatment with iodine and water, optionally in the presence of a weak base such as a pyridine, lutidine, or collidine. In some instances, oxidation is done under anhydrous conditions using tert-Butyl hydroperoxide or (1S)-(+)-(10-camphorsulfonyl)-oxaziridine (CSO). In some methods, a capping step is performed following oxidation. A second capping step allows for surface drying, as residual water from oxidation that may persist can inhibit subsequent coupling. Following oxidation, the surface and growing oligonucleic acid is optionally washed. In some instances, the oxidation step is substituted with a sulfurization step to obtain oligonucleotide phosphorothioates, wherein any capping steps can be performed after the sulfurization. Many reagents are capable of the efficient sulfur transfer, including, but not limited to, 3-(Dimethylaminomethylidene)amino)-3H-1,2,4-dithiazole-3-thione, DDTT, 3H-1,2-benzodithiol-3-one 1,1-dioxide, also known as Beaucage reagent, and N,N,N′N′-Tetraethylthiuram disulfide (TETD). 
     In order for a subsequent cycle of nucleoside incorporation to occur through coupling, a protected 5′ end of the surface bound growing oligonucleic acid must be removed so that the primary hydroxyl group can react with a next nucleoside phosphoramidite. In some instances, the protecting group is DMT and deblocking occurs with trichloroacetic acid in dichloromethane. 
     In some cases, following oligonucleic acid synthesis, oligonucleic acids are released from their bound surface and pooled. In some instances, the pooled oligonucleic acids are assembled into a larger nucleic acid, such as a gene. In some instances, larger oligonucleic acids are generated through ligation reactions to join the synthesized oligonucleic acids. One example of a ligation reaction is polymerase chain assembly (PCA). 
     In some instances, a surface is functionalized with a hydrophobic set of molecules, where the hydrophobic set of molecules is configured to hold an extracted oligonucleic acid molecule. In some cases, a hydrophobic feature corresponds to a well, and an oligonucleic acid molecule is held in the feature during an assembly process, for example, during PCA. In some cases, a hydrophobic feature corresponds to a well and an assembled oligonucleic acid is stored within the well. 
     In some instances, error correction is performed on synthesized oligonucleic acids and/or assembled products. An example strategy for error correction involves site-directed mutagenesis by overlap extension PCR to correct errors, which is optionally coupled with two or more rounds of cloning and sequencing. In certain instances, double-stranded nucleic acids with mismatches, bulges and small loops, chemically altered bases and/or other heteroduplexes are selectively removed from populations of correctly synthesized nucleic acids. In some instances, error correction is performed using proteins/enzymes that recognize and bind to or next to mismatched or unpaired bases within double-stranded nucleic acids to create a single or double-strand break or to initiate a strand transfer transposition event. Non-limiting examples of proteins/enzymes for error correction include endonucleases (T7 Endonuclease I,  E. coli  Endonuclease V, T4 Endonuclease VII, mung bean nuclease, Cell,  E. coli  Endonuclease IV, UVDE), restriction enzymes, glycosylases, ribonucleases, mismatch repair enzymes, resolvases, helicases, ligases, antibodies specific for mismatches, and their variants. Examples of specific error correction enzymes include T4 endonuclease 7, T7 endonuclease 1, S1, mung bean endonuclease, MutY, MutS, MutH, MutL, cleavase, CELI, and HINF1. In some cases, DNA mismatch-binding protein MutS ( Thermus aquaticus ) is used to remove failure products from a population of synthesized products. In some instances, error correction is performed using the enzyme Correctase. In some cases, error correction is performed using SURVEYOR endonuclease (Transgenomic), a mismatch-specific DNA endonuclease that scans for known and unknown mutations and polymorphisms for heteroduplex DNA. 
     Computer Systems 
     In various aspects, any of the systems described herein are operably linked to a computer and are optionally automated through a computer either locally or remotely. In various instances, the methods and systems of the invention further comprise software programs on computer systems and use thereof. Accordingly, computerized control for the synchronization of the dispense/vacuum/refill functions such as orchestrating and synchronizing the material deposition device movement, dispense action and vacuum actuation are within the bounds of the invention. In some instances, the computer systems are programmed to interface between the user specified base sequence and the position of a material deposition device to deliver the correct reagents to specified regions of the surface. 
     The computer system  900  illustrated in  FIG. 9  may be understood as a logical apparatus that can read instructions from media  911  and/or a network port  905 , which can optionally be connected to server  909  having fixed media  912 . The system, such as shown in  FIG. 9  can include a CPU  901 , disk drives  903 , optional input devices such as keyboard  915  and/or mouse  916  and optional monitor  907 . Data communication can be achieved through the indicated communication medium to a server at a local or a remote location. The communication medium can include any means of transmitting and/or receiving data. For example, the communication medium can be a network connection, a wireless connection or an internet connection. Such a connection can provide for communication over the World Wide Web. It is envisioned that data relating to the present disclosure can be transmitted over such networks or connections for reception and/or review by a party  922  as illustrated in  FIG. 9 . 
       FIG. 10  is a block diagram illustrating a first example architecture of a computer system  1000  that can be used in connection with example instances of the present invention. As depicted in  FIG. 10 , the example computer system can include a processor  1002  for processing instructions. Non-limiting examples of processors include: Intel Xeon™ processor, AMD Opteron™ processor, Samsung 32-bit RISC ARM 1176JZ(F)-S v1.0™ processor, ARM Cortex-A8 Samsung S5PC100™ processor, ARM Cortex-A8 Apple A4™ processor, Marvell PXA 930™ processor, or a functionally-equivalent processor. Multiple threads of execution can be used for parallel processing. In some instances, multiple processors or processors with multiple cores can also be used, whether in a single computer system, in a cluster, or distributed across systems over a network comprising a plurality of computers, cell phones, and/or personal data assistant devices. 
     As illustrated in  FIG. 10 , a high speed cache  1004  can be connected to, or incorporated in, the processor  1002  to provide a high speed memory for instructions or data that have been recently, or are frequently, used by processor  1002 . The processor  1002  is connected to a north bridge  1006  by a processor bus  1008 . The north bridge  906  is connected to random access memory (RAM)  1010  by a memory bus  1012  and manages access to the RAM  1010  by the processor  902 . The north bridge  1006  is also connected to a south bridge  1014  by a chipset bus  1016 . The south bridge  1014  is, in turn, connected to a peripheral bus  1018 . The peripheral bus can be, for example, PCI, PCI-X, PCI Express, or other peripheral bus. The north bridge and south bridge are often referred to as a processor chipset and manage data transfer between the processor, RAM, and peripheral components on the peripheral bus  1018 . In some alternative architectures, the functionality of the north bridge can be incorporated into the processor instead of using a separate north bridge chip. 
     In some instances, the system  1000  includes an accelerator card  1022  attached to the peripheral bus  1018 . The accelerator can include field programmable gate arrays (FPGAs) or other hardware for accelerating certain processing. For example, an accelerator can be used for adaptive data restructuring or to evaluate algebraic expressions used in extended set processing. 
     Software and data are stored in external storage  1024  and can be loaded into RAM  1010  and/or cache  1004  for use by the processor. The system  1000  includes an operating system for managing system resources; non-limiting examples of operating systems include: Linux, Windows™, MACOS™, BlackBerry OS™, iOS™, and other functionally-equivalent operating systems, as well as application software running on top of the operating system for managing data storage and optimization in accordance with example instances of the present invention. 
     In this example, the system  1000  also includes network interface cards (NICs)  1020  and  921  connected to the peripheral bus for providing network interfaces to external storage, such as Network Attached Storage (NAS) and other computer systems that can be used for distributed parallel processing. 
       FIG. 11  is a diagram showing a network  1100  with a plurality of computer systems  1102   a , and  1102   b , a plurality of cell phones and personal data assistants  1102   c , and Network Attached Storage (NAS)  1104   a , and  1104   b . In example instances, systems  1102   a ,  1102   b , and  1102   c  can manage data storage and optimize data access for data stored in Network Attached Storage (NAS)  1104   a  and  1104   b . A mathematical model can be used for the data and be evaluated using distributed parallel processing across computer systems  1102   a , and  1102   b , and cell phone and personal data assistant systems  1102   c . Computer systems  1102   a , and  1102   b , and cell phone and personal data assistant systems  1102   c  can also provide parallel processing for adaptive data restructuring of the data stored in Network Attached Storage (NAS)  1104   a  and  1104   b .  FIG. 11  illustrates an example only, and a wide variety of other computer architectures and systems can be used in conjunction with the various instances of the present invention. For example, a blade server can be used to provide parallel processing. Processor blades can be connected through a back plane to provide parallel processing. Storage can also be connected to the back plane or as Network Attached Storage (NAS) through a separate network interface. 
     In some example instances, processors can maintain separate memory spaces and transmit data through network interfaces, back plane or other connectors for parallel processing by other processors. In other instances, some or all of the processors can use a shared virtual address memory space. 
       FIG. 12  is a block diagram of a multiprocessor computer system  1200  using a shared virtual address memory space in accordance with an example embodiment. The system includes a plurality of processors  1202   a - f  that can access a shared memory subsystem  1204 . The system incorporates a plurality of programmable hardware memory algorithm processors (MAPs)  1206   a - f  in the memory subsystem  1204 . Each MAP  1206   a - f  can comprise a memory  1208   a - f  and one or more field programmable gate arrays (FPGAs)  1210   a - f . The MAP provides a configurable functional unit and particular algorithms or portions of algorithms can be provided to the FPGAs  1210   a - f  for processing in close coordination with a respective processor. For example, the MAPs can be used to evaluate algebraic expressions regarding the data model and to perform adaptive data restructuring in example instances. In this example, each MAP is globally accessible by all of the processors for these purposes. In one configuration, each MAP can use Direct Memory Access (DMA) to access an associated memory  1208   a - f , allowing it to execute tasks independently of, and asynchronously from, the respective microprocessor  1202   a - 1202   f . In this configuration, a MAP can feed results directly to another MAP for pipelining and parallel execution of algorithms. 
     The above computer architectures and systems are examples only, and a wide variety of other computer, cell phone, and personal data assistant architectures and systems can be used in connection with example instances, including systems using any combination of general processors, co-processors, FPGAs and other programmable logic devices, system on chips (SOCs), application specific integrated circuits (ASICs), and other processing and logic elements. In some instances, all or part of the computer system can be implemented in software or hardware. Any variety of data storage media can be used in connection with example instances, including random access memory, hard drives, flash memory, tape drives, disk arrays, Network Attached Storage (NAS) and other local or distributed data storage devices and systems. 
     In example instances, the computer system can be implemented using software modules executing on any of the above or other computer architectures and systems. In other instances, the functions of the system can be implemented partially or completely in firmware, programmable logic devices such as field programmable gate arrays (FPGAs) as referenced in  FIG. 12 , system on chips (SOCs), application specific integrated circuits (ASICs), or other processing and logic elements. For example, the Set Processor and Optimizer can be implemented with hardware acceleration through the use of a hardware accelerator card, such as accelerator card  922  illustrated in  FIG. 9 . 
     The following examples are set forth to illustrate more clearly the principle and practice of instances disclosed herein to those skilled in the art and are not to be construed as limiting the scope of any claimed instances. Unless otherwise stated, all parts and percentages are on a weight basis. 
     EXAMPLES 
     Example 1: Differential Functionalization of a Surface 
     A structure comprising a 1000 Å layer of silicon dioxide on its top surface was differentially functionalized using a first set of molecules comprising a passive agent (an agent that lacks a reactive group for nucleoside coupling) and a second set of molecules comprising an active agent (an agent that includes an reactive group for nucleoside coupling). The top surface of the structure was coated with the first set of molecules comprising (tridecafluoro-1, 1, 2, 2-tetrahydrooctyl)trichlorosilane using a YES-1224P vapor deposition oven system (Yield Engineering Systems) with the following parameters: 1 torr, 60 min, 70° C. vaporizer. The thickness of the first coated layer was measured using an ellipsometer (J. A. Woollam) to be about 8 Å. The contact angle was measured to be about 115 degrees using a Kruss GmbH instrument. 
     The passively coated surface was patterned by application of deep ultraviolet (DUV) light to the top surface of the surface through a quartz mask with chrome patterns, where the mask was positioned on top of the structure so that only distinct regions of the top surface of the surface were exposed to the DUV light. DUV light was applied using a Hamamatsu L12530 EX-mini Compact Excimer Lamp Light Source for a total of 60 seconds. The excimer lamp delivers 50 mW/cm 2  power at 172 nm wavelength sufficient to cleave the fluoro-silane passive layer from the exposed region of the silicon surface. The contact angle was measured as before and was less than 10 degrees. Water was applied to the structure and only exposed areas were wetted, while the original fluoropolymer areas not exposed to deep UV light repelled the water. 
     The passively patterned surface was rinsed with water and subsequently coated with 3-glycidoxypropyltrimethoxysilane (GOPS) by vapor deposition as before (YES). The contact angle was measured at around 65 degrees.  FIG. 13  is a graphical representation of the contact angles measured on the same areas of the surface after fluoro-silane coating (trace A; about 115 degrees), DUV light exposure (trace B; less than about 10 degrees) and after GOPS deposition (trace C; about 65 degrees). 
     Example 2: Oligonucleic Acid Synthesis Using a Differentially Functionalized Surface 
     The structure having a differentially functionalized surface of Example 1 was used as a support for the synthesis of 50-mer oligonucleic acids. The structure was assembled into a flow cell and connected to an Applied Biosystems ABI394 DNA Synthesizer. Synthesis of the 50-mer oligonucleic acids was performed using the methods of Table 2. 
     
       
         
           
               
               
               
               
             
               
                 TABLE 2 
               
               
                   
               
               
                 General DNA Synthesis Process Name 
                 New Process step 
                 Time 
                 Step # 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                 WASH (Acetonitrile Wash Flow) 
                 Acetonitrile System Flush 
                 4 
                 1 
               
               
                   
                 Acetonitrile to Flowcell 
                 23 
                 2 
               
               
                   
                 N2 System Flush 
                 4 
                 3 
               
               
                 DNA BASE ADDITION 
                 Activator Manifold Flush 
                 1.7 
                 4 
               
               
                 (Phosphoramidite + Activator Flow) 
                 Activator to Flowcell 
                 6 
                 5 
               
               
                   
                 Incubate 
                 1 
                 6 
               
               
                   
                 Activator + 
                 6 
                 7 
               
               
                   
                 Phosphoramidite to 
               
               
                   
                 Flowcell 
               
               
                   
                 Activator to Flowcell 
                 0.5 
                 8 
               
               
                   
                 Activator + 
                 2.5 
                 9 
               
               
                   
                 Phosphoramidite to 
               
               
                   
                 Flowcell 
               
               
                   
                 Activator to Flowcell 
                 0.5 
                 10 
               
               
                   
                 Activator + 
                 2.5 
                 11 
               
               
                   
                 Phosphoramidite to 
               
               
                   
                 Flowcell 
               
               
                   
                 Activator to Flowcell 
                 0.5 
                 12 
               
               
                   
                 Activator + 
                 2.5 
                 13 
               
               
                   
                 Phosphoramidite to 
               
               
                   
                 Flowcell 
               
               
                   
                 Incubate for 25 sec 
                 25 
                 14 
               
               
                 WASH (Acetonitrile Wash Flow) 
                 Acetonitrile System Flush 
                 4 
                 15 
               
               
                   
                 Acetonitrile to Flowcell 
                 15 
                 16 
               
               
                   
                 N2 System Flush 
                 4 
                 17 
               
               
                 DNA BASE ADDITION 
                 Activator Manifold Flush 
                 1.7 
                 18 
               
               
                 (Phosphoramidite + Activator Flow) 
                 Activator to Flowcell 
                 5 
                 19 
               
               
                   
                 Activator + 
                 12 
                 20 
               
               
                   
                 Phosphoramidite to 
               
               
                   
                 Flowcell 
               
               
                   
                 Incubate for 25 sec 
                 25 
                 21 
               
               
                 WASH (Acetonitrile Wash Flow) 
                 Acetonitrile System Flush 
                 4 
                 22 
               
               
                   
                 Acetonitrile to Flowcell 
                 15 
                 23 
               
               
                   
                 N2 System Flush 
                 4 
                 24 
               
               
                   
                 Acetonitrile System Flush 
                 4 
                 25 
               
               
                 OXIDATION (Oxidizer Flow) 
                 Oxidizer to Flowcell 
                 12 
                 26 
               
               
                 WASH (Acetonitrile Wash Flow) 
                 Acetonitrile System Flush 
                 4 
                 27 
               
               
                   
                 N2 System Flush 
                 4 
                 28 
               
               
                   
                 Acetonitrile System Flush 
                 4 
                 29 
               
               
                   
                 Acetonitrile to Flowcell 
                 10 
                 30 
               
               
                   
                 Acetonitrile System Flush 
                 4 
                 31 
               
               
                   
                 Acetonitrile to Flowcell 
                 10 
                 32 
               
               
                   
                 N2 System Flush 
                 4 
                 33 
               
               
                   
                 Acetonitrile System Flush 
                 4 
                 34 
               
               
                   
                 Acetonitrile to Flowcell 
                 23 
                 35 
               
               
                   
                 N2 System Flush 
                 4 
                 36 
               
               
                 DEBLOCKING (Deblock Flow) 
                 Deblock to Flowcell 
                 30 
                 37 
               
               
                 WASH (Acetonitrile Wash Flow) 
                 Acetonitrile System Flush 
                 4 
                 38 
               
               
                   
                 N2 System Flush 
                 4 
                 39 
               
               
                   
                 Acetonitrile System Flush 
                 4 
                 40 
               
               
                   
                 Acetonitrile to Flowcell 
                 12 
                 41 
               
               
                   
                 N2 System Flush 
                 4 
                 42 
               
               
                   
                 Acetonitrile System Flush 
                 5 
                 43 
               
               
                   
                 Acetonitrile to Flowcell 
                 12 
                 44 
               
               
                   
               
            
           
         
       
     
     Synthesized oligonucleic acids were extracted from the surface and analyzed on a BioAnalyzer chip. Oligonucleic acid products were PCR amplified, cloned and Sanger sequenced.  FIG. 14  is a digital image capture of the surface of the structure after oligonucleic acid synthesis, where the oligonucleic acid synthesis extends from layers coated with active agent. The areas of the surface comprising synthesized oligonucleic acids appear clear (oligonucleic acid synthesis occurred only on GOPS covered areas and not on fluorosilane covered areas). The areas of the surface which are dark correspond to the fluoro-silane layer that was not exposed to DUV light.  FIG. 14  (part A) is a digital image capture of the surface at a 5× objective and  FIG. 14  (part B) is a digital image capture of the surface at a 50× objective. The arrow in  FIG. 14  (part B) indicates the width of the band at 50 um. 
     Example 3: Differential Functionalization of a Surface to Generate a Pattern of Distinct Loci within Clusters 
     A structure comprising a 1000 Å layer of silicon dioxide on its top surface was differentially functionalized using a first set of molecules comprising a passive agent (an agent that lacks a reactive group for nucleoside coupling) and a second set of molecules comprising an active agent (an agent that includes an reactive group for nucleoside coupling). The top surface of the silicon surface was coated with the first set of molecules comprising (tridecafluoro-1, 1, 2, 2-tetrahydrooctyl)trichlorosilane as described in Example 1. The passively coated surface was patterned by application of DUV light to the top surface of the structure through a quartz mask with chrome patterns, where the mask was positioned on top of the structure so that only distinct regions of the top surface of the structure were exposed to the DUV light. DUV light was applied using a Hamamatsu L12530 EX-mini Compact Excimer Lamp Light Source for a total of 60 seconds at about 1 cm distance with an nitrogen gas backfill. The surface was patterned to have a plurality of clusters, with each cluster having 121 reaction sites or loci for oligonucleic acid synthesis. The passively patterned surface was rinsed with water and subsequently deposited with 3-glycidoxypropyltrimethoxysilane (GOPS) by vapor deposition as before (YES) to coat each of the loci. 
     Example 4: Oligonucleic Acid Synthesis on Distinct Loci of a Differentially Functionalized Surface 
     The differentially functionalized surface of Example 3 was used as a support for the synthesis of 50-mer oligonucleic acids. The structure was assembled into a flow cell and connected to an Applied Biosystems ABI394 DNA Synthesizer. Synthesis of the 50-mer oligonucleic acids was performed using the methods of Table 2. Synthesized oligonucleic acids were extracted from the surface and analyzed on a BioAnalyzer chip. Oligonucleic acid products were PCR amplified, cloned and Sanger sequenced. 
       FIG. 15  is a digital image capture of the surface of the structure after oligonucleic acid synthesis. The areas of the surface comprising synthesized oligonucleic acids appear clear. The areas of the surface which are dark correspond to the fluorosilane layer that was not exposed to DUV light. 
     Example 5: Comparison of Surface Functionalization Methods 
     Surfaces were differentially functionalized with an active and passive layer using a reverse photoresist process, a forward photoresist process, and a process employing deep UV light. The steps of each surface preparation method are listed in Table 3. For each method, the passive and active layers were deposited by chemical vapor deposition. Each prepared surface was used as a support for the synthesis of oligonucleic acids on areas of active functionalization. 
     
       
         
           
               
               
               
             
               
                 TABLE 3 
               
               
                   
               
               
                 Reverse photoresist (PR) 
                 Forward photoresist (PR) 
                 Deep UV 
               
               
                   
               
             
            
               
                 1) Wet clean (optional) 
                 1) Wet clean (optional) 
                 1) Wet clean (optional) 
               
               
                 2) Dry clean (O2 plasma) 
                 2) Dry clean (O2 plasma) 
                 2) Dry clean (O2) 
               
               
                 3) Deposition of active layer 
                 3) PR coat 
                 3) Deposition of passive layer 
               
               
                 4) PR coat 
                 4) PR Exposure 
                 4) Deep UV exposure 
               
               
                 5) PR Exposure 
                 5) PR development and bake 
                 5) Deposition of active layer 
               
               
                 6) PR development and bake 
                 6) Dry clean (O2) 
                 6) Activation of active layer 
               
               
                 7) Dry clean (O2) 
                 7) Deposition of passive layer 
               
               
                 8) Deposition of passive layer 
                 8) PR strip 
               
               
                 9) PR strip 
                 9) Deposition of active layer 
               
               
                 10) Activation of active layer 
                 10) Activation of active layer 
               
               
                   
               
            
           
         
       
     
       FIG. 16  shows digital image captures of surfaces differentially functionalized with an active and passive layer by the different process steps outlined in Table 3. Each photograph shows a surface after oligonucleic acid synthesis on a layer of active agent.  FIG. 16  (part A) shows 10× and 50× magnifications of a surface functionalized using a forward photoresist process as described in Example 5.  FIG. 16  (part B) shows 10× and 50× magnifications of a surface functionalized using a reverse photoresist process as described in Example 5.  FIG. 16  (part C) shows 10× and 50× magnifications of a surface functionalized using a deep UV process as described in Example 5. In the images, areas of the surface comprising synthesized oligonucleic acids appear as clear while generally circular areas of the surface. In contrast, areas coated with the passive layer appear darker in the images. 
     DNA intensity profiles were generated oligonucleic acids synthesized on surfaces differentially functionalized by the various process steps outlined in Table 3.  FIG. 17A  shows an intensity profile for oligonucleic acids synthesized on a surface functionalized using a forward photoresist process as described in Example 5. The X axis on the plot corresponds to the distance across each locus and the Y axis on the plot corresponds to the intensity of the signal. The plot has a top line, a middle line  1601 , and a bottom line, corresponding to blue, green, and red wavelength recordings using a Nikon DS Fi2 camera. Each line represents an intensity signal obtained from a different light sensor on the camera. The middle line  1601  is a recording of light emissions from about 500 nm to about 530 nm in wavelength. The middle line  1601  was resulted in generation of the most effective contrast for measuring the sample oligonucleotides on the surface. White light was generated using a Nikon Eclipse L200 microscope. 
       FIG. 17B  shows an intensity profile for oligonucleic acids synthesized on a surface functionalized using a reverse photoresist process as described in Example 5. The X axis on the plot corresponds to the distance across each locus and the Y axis on the plot corresponds to the intensity of the signal. The plot has a top line, a middle line  1602 , and a bottom line, corresponding to blue, green, and red wavelength recordings using a Nikon DS Fi2 camera. Each line represents an intensity signal obtained from a different light sensor on the camera. The middle line  1602  is a recording of light emissions from about 500 nm to about 530 nm in wavelength. The middle line  1602  was resulted in generation of the most effective contrast for measuring the sample oligonucleotides on the surface. White light was generated using a Nikon Eclipse L200 microscope. 
       FIG. 17C  shows an intensity profile for oligonucleic acids synthesized on a surface functionalized using a deep UV process as described in Example 5. The X axis on the plot corresponds to the distance across each locus and the Y axis on the plot corresponds to the intensity of the signal. The plot has a top line, a middle line  1603 , and a bottom line, corresponding to blue, green, and red wavelength recordings using a Nikon DS Fi2 camera. Each line represents an intensity signal obtained from a different light sensor on the camera. The middle line  1603  is a recording of light emissions from about 500 nm to about 530 nm in wavelength. The middle line  1603  was resulted in generation of the most effective contrast for measuring the sample oligonucleotides on the surface. White light was generated using a Nikon Eclipse L200 microscope. 
     In the forward resist process, the photoresist (PR) was coated prior to active layer coating. In the reverse process, PR was deposited after active layer coating and residues remaining on the surface created a non-homogeneous layer of synthesized oligonucleic acids. The surface patterned with deep UV had the highest percentage of uniformity among synthesized oligonucleic acid strands. The percentage of non-uniformity was about 31% for the reverse PR process, about 39% for the forward PR process, and about 23% for the deep UV process (and likewise the percent of uniformity was about 69% for the reverse PR process, about 61% for the forward PR process, and about 77% for the deep UV process). The non-uniformity was calculated by dividing the amplitude of signal variation by the total signal intensity. As shown in the trace highlighted in  FIGS. 17A-17C , the signal variation was greater for oligonucleic acids synthesized on surfaces prepared using the forward and reverse photoresist processes than for the oligonucleic acids synthesized on surfaces prepared using the deep UV process. 
     Example 6: Patterning a Functionalized Material on a Surface 
     A patterned functionalized surface was created on fluorinated silicon plates using a Ushio MinExcimer deep UV (DUV) lamp ( FIG. 21 ) and quartz mask with Suss MA-6 mask aligner. The quartz mask allows some of the UV light to go through at 172 nm. A chrome or dielectric cover is used to create shadows on the chip. The mask was held in place by loading the mask into the mask aligner and the vision system was aligned on the alignment fiducial of the mask. The chip was loaded into the alignment system and the mask was aligned over the chip using screws on the mask aligner and visualizing the chip and the mask with a microscope. A controlled atmosphere was created between the mask and the substrate using a backfill of nitrogen gas. The mask was then brought into close contact with the chip. Once the mask was aligned correctly over the chip, the microscope was removed and the DUV lamp was moved into place over the mask. A controlled atmosphere was also created between the mask and the lamp using nitrogen backfill. DUV light was applied to activate the chip surface chemistry. The chip was exposed to DUV for about 100 seconds using the Ushio MinExcimer lamp, providing approximately 10 mW/cm 2 . Ozone created by the low wavelength light was purged using the nitrogen backfill and ozone exhaust. After DUV exposure, 3-glycidoxypropyltrimethoxysilane (GOPS) was deposited onto the surface of the chip and the surface was activated for DNA synthesis. 
     The apparatus used for patterning is shown in  FIGS. 18-19 .  FIG. 18  depicts a lamp power unit  1801  which powers the illumination unit  1804  which provides the DUV light. The mask his held in the mask holder  1803 . Ozone is eliminated from the system using a nitrogen backfill  1805  and an ozone exhaust  1802 . In some instances, the ozone exhaust  1702  is optional.  FIG. 19  depicts an illumination unit  1901 , a plate with window  1903  for location of the illumination unit on the modified mask plate, and a nitrogen backfill for the space between the light source and the mask  1902 . A tubing loop with punched holes blowing nitrogen is introduced around the substrate during loading, alignment and exposure to remove oxygen and prevent ozone formation around the exposed area. 
     Alignment of the loci was confirmed using fiducials  2201 . ( FIG. 22 ) The diameter of the loci after the process was completed varied from about 51 μm to about 58 μm. This variation in loci diameter was observed over the surface of the chip with differences observed between the center of the chip and the edges of the chip. DNA yield and quality (error rate) on the surface was determined to be similar to standard chips (data not shown). NGS was done on the DNA spots and an error rate was determined to be similar to that observed with standard chips. 
     In a separate run, surfaces were prepared using the cylinder UV lamp in pattern for extending oligonucleic acids in parallel lines on the surface. Oligonucleic acid extension was observed wherein each line was about 3 um in width, and having a 6 um pitch (image capture not shown). Measurements for line width in one image capture included 2.90 um, 3.08 um, and 2.71 um. 
     Example 7: Patterning a Surface Using a Flat Lamp 
     A patterned functionalized surface was created on a fluorinated silicon dioxide coated plate using a flat ultraviolet lamp (Hamamatsu deep UV (DUV) lamp,  FIG. 20 ) and quartz mask with a mask aligner. The quartz mask allows UV light to go through at 172 nm. The lamp has a flat shape that allows the surface to be exposed to the DUV light with increased uniformity across the plate surface. The mask is held in place by loading the mask into the mask aligner and the vision system is aligned on the alignment fiducial of the mask. The plate is loaded into the alignment system and the mask is aligned over the chip using screws on the mask aligner and visualizing the plate and the mask with a microscope. A controlled atmosphere is created between the mask and the substrate using a purge combined with a backfill of nitrogen gas. The mask is then brought into close contact with the chip. Once the mask is aligned correctly over the chip, the microscope is removed and the DUV lamp is moved into place over the mask. A controlled atmosphere is also created between the mask and the lamp using the purge and nitrogen backfill. DUV light is applied to activate the chip surface chemistry. The chip is exposed to DUV for about 20 seconds using the lamp, providing approximately 50 mW/cm 2 . Ozone created by the low wavelength light is purged using the nitrogen backfill and ozone exhaust. 
     A TOF-SIMS analysis of an area 150 um×150 um was performed to analyze surface chemistry. Referring to  FIG. 23 , the bottom chart is a background reference reading from a silicon dioxide coated plate; the top chart is a reading from a silicon dioxide coated plate having fluorosilane layer coated on top; and the middle chart is a reading taken after DUV exposure to a previously fluorinated section of the chip. As can be seen in the chart, fluorosilane is not detected in the DUV treated section. The X axis is for Intensity counts and the Y axis is for Mass (u). 
     Example 8: Patterning Oligonucleic Acids on a Surface 
     A SOI wafer is provided and prepared prior to application of a set of molecules by a wet or dry cleaning process. The wafer is deposited with 3-glycidoxypropyltrimethoxysilane (GOPS) and nucleotide extension reactions are performed to extend from the surface oligonucleic acids at least 20 bases in length. A protecting group having a trityl group is applied to the terminal end of the oligonucleic acids. The layer of active agent and oligonucleic acid platform is subsequently patterned by removing the layers from defined regions of the surface via exposure to EMR at 172 nm. A shadow mask is positioned over the surface so that only the defined regions are exposed to EMR through openings in the shadow mask. The layer of active agent and platform oligonucleic acids coated on the exposed regions of the surface is cleaved from the surface and washed away with a wash solution. After the surface is patterned, the exposed regions of the surface are exposed to tridecafluoro-1,1,2,2-tetrahydrooctyl)trichlorosilane or tridecafluoro-1,1,2,2-tetrahydrooctyl)trimethoxysilane. The platform oligonucleic acids de-protected and extension of a predetermined sequence of oligonucleic acids 100 bases in length is performed. The resultant surface will comprise a cluster of loci within a diameter of 1.15 mm wherein each loci has a width of 10 um. The loci each comprise an oligonucleic acid which is different from that extending on another locus. Each cluster will comprise about 121 loci and the loci will collectively encode predetermined sequence for a single preselected nucleic acid, e.g., a gene. 
     Example 9: Patterning a Surface Using a Large Flat Lamp 
     A patterned functionalized surface is created on a fluorinated silicon plate using a flat ultraviolet lamp (Quark deep UV (DUV) lamp) and quartz mask with a mask aligner. The quartz mask allows UV light to go through at 172 nm. A chrome or dielectric cover is used to create shadows on the chip. The lamp has a flat shape that allows the surface to be exposed to the DUV light with increased uniformity across the chip surface over an increased surface area. The mask is held in place by loading the mask into the mask aligner and the vision system is aligned on the alignment fiducial of the mask. The plate is loaded into the alignment system and the mask is aligned over the chip using screws on the mask aligner and visualizing the chip and the mask with a microscope. A controlled atmosphere is created between the mask and the substrate using a purge combined with a backfill of nitrogen gas. The mask is then brought into close contact with the chip. Once the mask is aligned correctly over the chip, the microscope is removed and the DUV lamp is moved into place over the mask. A controlled atmosphere is also created between the mask and the lamp using the purge and nitrogen backfill. DUV light is applied to activate the chip surface chemistry. The chip is exposed to DUV for about 35 seconds using the lamp, providing approximately 30 mW/cm 2 . Ozone created by the low wavelength light is purged using the nitrogen backfill and ozone exhaust. After DUV exposure, 3-glycidoxypropyltrimethoxysilane (GOPS) is deposited onto the surface of the chip and the surface is activated for DNA synthesis. 
     Example 10: Patterning a Surface Using a Laser 
     A patterned functionalized surface is created on a fluorinated silicon plate using a laser. The plate is aligned to a reference to guide the laser and a controlled atmosphere is created between the plate and the laser using a purge and nitrogen backfill system. The laser is applied using pulses while moving the chip synchronized with the laser pulses to create a pattern of exposed areas on the chip to activate the chip surface chemistry. After DUV exposure, 3-glycidoxypropyltrimethoxysilane (GOPS) is deposited onto the surface of the chip and the surface is activated for DNA synthesis. 
     Example 11: Preparing a Nylon Substrate 
     A nylon surface is created using a molecular layer deposition of nylon for functionalization and nucleic acid synthesis. A nylon film is deposited on a tape made from another synthetic material. (Alternatively, a nylon tape or silicon wafer is used.) The surface is then dosed with glutaryl chloride for 10 seconds (room temperature ampoule, 10 sccm N 2  carrier). The surface is purged 5 Torr N 2  for 20 seconds, evacuated for 5 seconds, purged 5 Torr N 2  for 20 seconds, and evacuated for 5 seconds. The surface is then dosed with ethylenediamine for 5 seconds (room temperature ampoule, 0 sccm N 2  carrier). The surface is purged 5 Torr N 2  for 20 seconds, evacuated for 5 seconds, purged 5 Torr N 2  for 20 seconds, and evacuated for 5 seconds. These steps are repeated for 30 cycles. 
     Example 12: Patterning a Nylon Surface Using a Flat Lamp 
     A patterned functionalized nylon is exposed to emissions from a flat UV lamp, a Hamamatsu deep UV (DUV) lamp, and quartz mask with mask aligner. The quartz mask allows UV light to go through at 172 nm. A chrome or dielectric cover is used to create shadows on the tape. The Hamamatsu lamp has a flat shape that allows the surface to be exposed to the DUV light with increased uniformity across the chip surface. The mask is held in place by the mask aligner and aligned over the tape using screws on the mask aligner and visualizing the chip and the mask with a microscope. Once the mask is aligned correctly over the chip, the microscope is removed and the DUV lamp is moved into place over the mask. DUV light is applied to activate the chip surface chemistry. After DUV exposure, the surface is activated for DNA synthesis. Increased DNA yields are observed using the nylon surface than those observed using a two-layered surface. 
     Example 13: Patterning a Nylon Surface Using a Laser 
     A patterned functionalized surface is created on a nylon flexible surface using a laser. The nylon flexible surface is aligned to a reference to guide the laser and a controlled atmosphere was created between the tape and the laser using a purge and nitrogen backfill system. The laser is applied using pulses while moving the tape synchronized with the laser pulses to create a pattern of exposed areas on the tape to activate the chip surface chemistry. After DUV exposure, the surface is activated for DNA synthesis. 
     Example 14: Patterning Passive Agent Using Microcontact Printing 
     Polydimethylsiloxane (PDMS) stamps are made using a UV photolithography process. A silicon wafer coated with photoresist is exposed to UV light through a mask, creating a pattern on the silicon wafer. The exposed wafer is then exposed to a solution of developer creating a master which is used to cast the PDMS stamp. The PDMS prepolymer is mixed with a curing agent and poured onto the prepared master. The cured stamp is then peeled from the template and is ready for inking. The finished stamp is about 100 μm to about 1 cm thick and the raised portions of the stamp range from about 1 μm to about 500 μm. 
     Stamps are inked with a solution containing a passive agent, tridecafluoro-1, 1, 2, 2-tetrahydrooctyl)trichlorosilane. After inking, the passive agent solution is transferred to a silicon plate. Care is taken to not deform the stamp while stamping the microchip. Each inked stamp is used to pattern three microchips before reloading the stamp. 
     Example 15: Patterning Active Agent Using Microcontact Printing 
     Polydimethylsiloxane (PDMS) stamps are made using a UV photolithography process. A silicon wafer coated with photoresist is exposed to UV light through a mask, creating a pattern on the silicon wafer. The exposed wafer is then exposed to a solution of developer creating a master which is used to cast the PDMS stamp. The PDMS prepolymer is mixed with a curing agent and poured onto the prepared master. The cured stamp is then peeled from the template and is ready for inking. The finished stamp is about 100 μm to about 1 cm thick and the raised portions of the stamp range from about 1 μm to about 500 μm. Stamps are inked with a solution containing an active agent, 3-glycidoxypropyltrimethoxysilane (GOPS). After inking, the active agent solution is transferred to a silicon plate. Care is taken to not deform the stamp while stamping the microchip. Each inked stamp is used to pattern three microchips before reloading the stamp. 
     Example 16: Gene Assembly Using PCA from Reaction Mixtures Transferred from a Device for Oligonucleotide Synthesis 
     A PCA reaction mixture is prepared as described in Table 4 using a population of oligonucleic acids synthesized using the protocol of Example 2 and surface preparation procedures consistent with EMR based protocols in Examples 3-14. 
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 4 
               
               
                   
                   
               
               
                   
                 PCA 
                 1 (×100 ul) 
                 final conc. 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                 H2O 
                 62.00 
                   
               
               
                   
                 5x Q5 buffer 
                 20.00 
                 1x 
               
            
           
           
               
               
               
               
               
            
               
                   
                 10 mM dNTP 
                 1.00 
                 100 
                 uM 
               
               
                   
                 BSA20 mg/ml 
                 5.00 
                 1 
                 mg/m l 
               
               
                   
                 Oligo mix 50 nM each 
                 10.00 
                 5 
                 nM 
               
            
           
           
               
               
               
               
            
               
                   
                 Q5 pol 2 U/ul 
                 2.00 
                 2 u/50 ul 
               
               
                   
                   
               
            
           
         
       
     
     Drops of about 400 nL were dispensed using a Mantis dispenser (Formulatrix, MA) on top of a cluster of loci which have been cleaved from the surface. A nanoreactor is chip is manually mated with the oligonucleotide device to pick up the droplets having the PCA reaction mixture. The droplets are picked up into the individual nanoreactors in the nanoreactor chip by releasing the nanoreactor from the oligonucleotide synthesis device immediately after pick-up. The nanoreactors are sealed with a Heat Sealing Film/Tape cover (Eppendorf) and placed in a suitably configured thermocycler that is constructed using a thermocycler kit (OpenPCR). 
     Alternatively, a pin-based system is used to contact a cluster of loci which have been cleaved from the surface. In such an arrangement, a pin having water on the tip contacts a cluster, transfers it to a well in a plate, such as a 96 or 384 well plate having PCA buffer in each well. 
     The following temperature protocol is used on the thermocycler: 
     1 cycle: 98 C, 45 seconds 
     40 cycles: 98 C, 15 seconds; 63 C, 45 seconds; 72 C, 60 seconds; 
     1 cycle: 72 C, 5 minutes 
     1 cycle: 4 C, hold 
     An aliquot of 0.50 ul is collected from individual wells and the aliquots are amplified in plastic tubes, in a PCR reaction mixture (Table 5) and according to the following thermocycler program, using a forward and a reverse primer: 
     Thermocycler: 
     1 cycle: 98 C, 30 seconds 
     30 cycles: 98 C, 7 seconds; 63 C, 30 seconds; 72 C, 90 seconds 
     1 cycle: 72 C, 5 minutes 
     1 cycle: 4 C, hold 
     
       
         
           
               
               
               
               
             
               
                   
                 TABLE 5 
               
               
                   
                   
               
               
                   
                 PCR 
                 1 (×25 ul) 
                 final conc. 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                   
                 H2O 
                 17.50 
                   
               
               
                   
                 5x Q5 buffer 
                 5.00 
                 1x 
               
            
           
           
               
               
               
               
               
            
               
                   
                 10 mM dNTP 
                 0.50 
                 200 
                 uM 
               
               
                   
                 F-primer 20 uM 
                 0.63 
                 0.5 
                 uM 
               
               
                   
                 R-primer 20 uM 
                 0.63 
                 0.5 
                 uM 
               
            
           
           
               
               
               
               
            
               
                   
                 BSA 20 mg/ml 
                 0.00 
                   
               
               
                   
                 Q5 pol 2 U/ul 
                 0.25 
                 1 u/50 ul 
               
               
                   
                 template (PCA assembly) 
                 0.50 
                 1 ul/50 ul rxn 
               
               
                   
                   
               
            
           
         
       
     
     While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is intended that the following claims define the scope of the invention and that methods and structures within the scope of these claims and their equivalents be covered thereby.