WO2005031349A2

WO2005031349A2 - Label-free methods for performing assays using a colorimetric resonant reflectance optical biosensor

Info

Publication number: WO2005031349A2
Application number: PCT/US2004/030893
Authority: WO
Inventors: Bo Lin; Brian T. Cunningham; Peter Li
Original assignee: Sru Biosystems, Inc.
Priority date: 2003-09-22
Filing date: 2004-09-22
Publication date: 2005-04-07
Also published as: EP1673632A2; US7264973B2; AU2004276749B2; CA2539187C; US20040132214A1; NZ577455A; WO2005031349A3; CA2539187A1; JP2007506107A; CN1879018A; AU2004276749A1

Abstract

The instant invention provides compositions and methods for determining cell interactions that are faster than conventional methods and that require the use of fewer reagents than conventional methods.

Description

LABEL-FREE METHODS FOR PERFORMING ASSAYS USING A COLORIMETRIC RESONANT REFLECTANCE OPTICAL BIOSENSOR

PRIORITY This application is a continuation-in-part of U.S. Application Ser. No. 10/237,641, filed Sept. 9, 2002, which is a continuation-in-part of U.S. Application Ser. No. 10/227,908, entitled "Amine Chemical Surface Activation Process And Test Method For A Plastic Colorimetric Resonant Biosensor," filed August 26, 2002, and U.S. Application Ser. No. 10/180,374, entitled "Colorimetric Resonant Biosensor Microarray Readout Instrument," filed June 26, 2002, and U.S. application Ser. No. 10/180,647, entitled "Colorimetric Resonant Biosensor Microtiter Plate Readout Instrument" filed June 26, 2002, which are continuations-in-part of U.S. Application Ser. No. 10/059,060, filed January 28, 2002 and U.S. Application Ser. No. 10/058,626, filed January 28, 2002, which are continuations-in-part of U.S. application Ser. No. 09/930,352, filed August 15, 2001, which claims the benefit of U.S. provisional application 60/244,312 filed October 30, 2000; U.S. provisional application 60/283,314 filed April 12, 2001; and U.S. provisional application 60/303,028 filed July 3, 2001, all of which are incorporated herein by reference in their entirety. TECHNICAL AREA OF THE INVENTION The invention relates to methods for detecting biomolecular interactions. The detection can occur without the use of labels and can be done in a high-throughput manner. The invention also relates to optical devices. BACKGROUND OF THE INVENTION With the completion of the sequencing of the human genome, one of the next grand challenges of molecular biology will be to understand how the many protein targets encoded by DNA interact with other proteins, small molecule pharmaceutical candidates, and a large host of enzymes and inhibitors. See e.g., Pandey & Mann, "Proteomics to study genes and genomes," Nature, 405, p. 837-846, 2000; Leigh Anderson et al, "Proteomics: applications in basic and applied biology," Current Opinion in Biotechnology, 11, p. 408-412, 2000; Patterson, "Proteomics: the industrialization of protein chemistry," Current Opinion in Biotechnology, 11, p. 413- 418, 2000; MacBeath & Schreiber, "Printing Proteins as Microarrays for High- Throughput Function Determination," Science, 289, p. 1760-1763, 2000; De Wildt et al., "Antibody arrays for high-throughput screening of antibody-antigen interactions," Nature Biotechnology, 18, p. 989-994, 2000. To this end, tools that have the ability to simultaneously quantify many different biomolecular interactions with high sensitivity will find application in pharmaceutical discovery, proteomics, and diagnostics. Further, for these tools to find widespread use, they must be simple to use, inexpensive to own and operate, and applicable to a wide range of analytes that can include, for example, polynucleotides, peptides, small proteins, antibodies, and even entire cells. Biosensors have been developed to detect a variety of biomolecular complexes including oligonucleotides, antibody-antigen interactions, hormone-receptor interactions, and enzyme-substrate interactions. In general, biosensors consist of two components: a highly specific recognition element and a transducer that converts the molecular recognition event into a quantifiable signal. Signal fransduction has been accomplished by many methods, including fluorescence, interferometry (Jenison et al, "Interference-based detection of nucleic acid targets on optically coated silicon," Nature Biotechnology, 19, p. 62-65; Lin et al, "A porous silicon-based optical interferometric biosensor," Science, 278, p. 840-843, 1997), and gravimetry (A. Cunningham, Bioanalytical Sensors, John Wiley & Sons (1998)). Of the optically-based fransduction methods, direct methods that do not require labeling of analytes with fluorescent compounds are of interest due to the relative assay simplicity and ability to study the interaction of small molecules and proteins that are not readily labeled. Direct optical methods include surface plasmon resonance (SPR) (Jordan & Corn, "Surface Plasmon Resonance Imaging Measurements of Electrostatic Biopolymer Adsorption onto Chemically Modified Gold Surfaces," Anal. Chem., 69:1449-1456 (1997)), grating couplers (Morhard et al, "Immobilization of antibodies in micropatterns for cell detection by optical diffraction," Sensors and Actuators B, 70, p. 232-242, 2000), ellipsometry (Jin et al, "A biosensor concept based on imaging ellipsometry for visualization of biomolecular interactions," Analytical Biochemistry, 232, p. 69-72, 1995), evanascent wave devices (Huber et al, "Direct optical immunosensing (sensitivity and selectivity)," Sensors and Actuators B, 6, p. 122-126, 1992), and reflectometry (Brecht & Gauglitz, "Optical probes and transducers," Biosensors and Bioelectronics, 10, p. 923-936, 1995). Theoretically predicted detection limits of these detection methods have been determined and experimentally confirmed to be feasible down to diagnostically relevant concentration ranges. However, to date, these methods have yet to yield commercially available high-throughput instruments that can perform high sensitivity assays without any type of label in a format that is readily compatible with the microtiter plate-based or icroarray-based infrastructure that is most often used for high-throughput biomolecular interaction analysis. Therefore, there is a need in the art for methods that can achieve these goals. SUMMARY OF THE INVENTION

In one embodiment the invention provides a vessel comprising a colorimetric resonant reflectance optical biosensor. The colorimetric resonant reflectance optical biosensor comprises an internal surface of the vessel. One or more specific binding substances are immobilized at two or more distinct locations on the internal surface of the vessel that comprises a colorimetric resonant reflectance optical biosensor. The vessel can comprise a microtiter well, test tube, petri dish or microfluidic channel. Another embodiment of the invention provides a microtiter plate comprising one or more microtiter wells, wherein a bottom surface of the one or more microtiter wells comprises a colorimetric resonant reflectance optical biosensor. One or more specific binding substances are immobilized at two or more distinct locations on the bottom surface of each microtiter well. Yet another embodiment of the invention provides a method of detecting binding of one or more types of cells to one or more specific binding substances. The method comprises applying the one or more types of cells to an internal surface of a vessel, wherein the internal surface of the vessel comprises a colorimetric resonant reflectance optical biosensor, wherein one or more specific binding substances are immobilized at two or more distinct locations on the internal surface of the vessel that comprises a colorimetric resonant reflectance optical biosensor. The vessel is illuminated with light and one or more peak wavelength values (PWVs) are determined for each distinct location. If the one or more cells have bound to one or more specific binding substances, then the PWV is shifted at the distinct location to which the one or more cells are bound. The vessel can be a microtiter well, microtiter plate, test tube, petri dish or microfluidic channel. The one or more specific binding substances can be arranged in an array of distinct locations on the internal surface of the vessel that comprises a colorimetric resonant reflectance optical biosensor. The distinct locations can define an array of spots of about 50-500 microns in diameter. The one or more specific binding substances can be immobilized on the internal surface of the vessel that comprises a colorimetric resonant reflectance optical biosensor by a method selected from the group consisting of physical adsorption, chemical binding, electrochemical binding, electrostatic binding, hydrophobic binding and hydrophilic binding. The one or more specific binding substances are selected from the group consisting of nucleic acids, peptides, protein solutions, peptide solutions, single or double stranded DNA solutions, RNA solutions, RNA-DNA hybrid solutions, solutions containing compounds from a combinatorial chemical library, antigen, polyclonal antibody, monoclonal antibody, single chain antibody (scFv), F(ab) fragment, F(ab')₂ fragment, Fv fragment, small organic molecule, cell, virus, bacteria, polymer and biological sample. Still another embodiment of the invention provides a method of detecting binding of one or more cells to one or more specific binding substances. The method comprises immobilizing one or more specific binding substances to two or more distinct locations on an internal surface of a vessel, wherein the internal surface of the vessel comprises a colorimetric resonant reflectance optical biosensor. The vessel is illuminated with light. One or more peak wavelength values (PWVs) are detected for each distinct location. One or more cells are applied to the internal surface of the vessel. The vessel is illuminated with light. One or more peak wavelength values (PWVs) are determined for each distinct location. The PWVs taken before the cells are added are compared to the PWVs that are taken after the cells are added. If the one or more cells have bound to a specific binding substance, then the PWV is shifted at the distinct location to which the cells are bound. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 A shows a cross-sectional view of a biosensor wherein light is shown as illuminating the bottom of the biosensor; however, light can illuminate the biosensor from either the top or the bottom. Figure IB shows a diagram of a biosensor wherein light is shown as illuminating the bottom of the biosensor; however, light can illuminate the biosensor from either the top or the bottom; Figure 2 shows an embodiment of a colorimetric resonant reflection biosensor comprising a one-dimensional grating made according to the methods and compositions of the invention. Figure 3A-B shows a grating comprising a rectangular grid of squares (Figure 3A) or holes (Figure 3B). Figure 4 shows a biosensor cross-section profile utilizing a sinusoidally varying grating profile. Figure 5 shows a resonant reflection or transmission filter structure consisting of a set of concentric rings. Figure 6 shows a resonant reflective or transmission filter structure comprising a hexagonal grid of holes (or a hexagonal grid of posts) that closely approximates the concentric circle structure of Figure 5 without requiring the illumination beam to be centered upon any particular location of the grid. Figure 7 shows a graphic representation of how adsorbed material, such as a protein monolayer, will increase the reflected wavelength of a biosensor that comprises a three-dimensional grating. Figure 8 shows three types of surface activation chemistry (Amine, Aldehyde, and Nickel) with corresponding chemical linker molecules that can be used to covalently attach various types of biomolecule receptors to a biosensor. Figure 9A-C shows methods that can be used to amplify the mass of a binding partner such as detected DNA or detected protein on the surface of a biosensor. Figure 10 shows resonance wavelength of a biosensor as a function of incident angle of detection beam. Figure 11 shows an example of the use of two coupled fibers to illuminate and collect reflected light from a biosensor. Figure 12 shows an example of the use of a beam splitter to enable illuminating and reflected light to share a common collimated optical path to a biosensor. Figure 13 shows a schematic diagram of a detection system. Figure 14 demonstrates an example of a biosensor that occurs on the tip of a fiber probe for in vivo detection of biochemical substances. Figure 15 shows dependence of peak resonance wavelength on the concentration of BSA dissolved in PBS, which was then allowed to dry on a biosensor surface. Figure 16A-B. Figure 16A shows results of streptavidin detection at various concentrations for a biosensor that has been activated with NH₂ surface chemistry linked to a biotin receptor molecule. Figure 16B shows a schematic demonstration of molecules bound to a biosensor. Figure 17A-B. Figure 17A shows an assay for detection of anti-goat IgG using a goat antibody receptor molecule. BSA blocking of a detection surface yields a clearly measurable background signal due to the mass of BSA incorporated on the biosensor. A 66 nM concentration of anti-goat IgG is easily measured above the background signal. Figure 17B shows a schematic demonstration of molecules bound to a biosensor. Figure 18A-B. Figure 18A shows a nonlabeled ELISA assay for interferon- gamma (INF-gamma) using an anti-human IgG INF-gamma receptor molecule, and a neural growth factor (NGF) negative control. Figure 18B shows a schematic demonstration of molecules bound to a biosensor. Figure 19A-B. Figure 19A shows detection of a 5-amino acid peptide (MW = 860) and subsequent cleavage of a pNA label (MW = 130) using enzyme caspase-3. Figure 19B shows a schematic demonstration of molecules bound to a biosensor. Figure 20A-B. Figure 20A shows resonant peak in liquid during continuous monitoring of the binding of three separate protein layers. Figure 20B shows a schematic demonstration of molecules bound to a biosensor. Figure 21A-B. Figure 21 A shows endpoint resonant frequencies mathematically determined from the data shown in Figure 21. Figure 2 IB shows a schematic demonstration of molecules bound to a biosensor. Figure 22A-B. Figure 22A shows kinetic binding measurement of IgG binding. Figure 22B shows a schematic demonstration of molecules bound to a biosensor. Figure 23A-B. Figure 23A shows kinetic measurement of a protease that cleaves bound protein from a biosensor surface. Figure 23B shows a schematic - demonstration of molecules bound to a biosensor. Figure 24 shows a plot of the peak resonant wavelength values for test solutions. The avidin solution was taken as the baseline reference for comparison to the Avidin+BSA and Avidin+b-BSA solutions. Addition of BSA to avidin results in only a small resonant wavelength increase, as the two proteins are not expected to interact. However, because biotin and avidin bind strongly (Kd = 10^"15M), the avidin+b-BSA solution will contain larger bound protein complexes. The peak resonant wavelength value of the avidin+b-BSA solution thus provides a large shift compared to avidin+BSA.

Figure 25 shows the PWV shift-referenced to a sensor with no chemical functional groups immobilized, recorded due to the attachment of NH₂, NH₂ + (NHS- PEG), and NH + (NHS-PEG-Biotin) molecules to the sensor surface. The error bars indicate the standard deviation of the recorded PWV shift over 7 microtiter plate wells. The data indicates that the sensor can differentiate between a clean surface, and one with immobilized NH₂, as well as clearly detecting the addition of the NHS-PEG (molecular weight approximately 2000 Daltons) molecule. The difference between surface immobilized NHS-PEG and NHS-PEG-Biotin (molecular weight approximately 3400 Dalton) is also measurable.

Figure 26A-C shows the PWV shift response as a function of time for biosensor wells when exposed to various concentrations of anti-biotin IgG (0-80 mg/ml) and allowed to incubate for 20 minutes. The NHS-PEG surface (Figure 26B) provides the lowest response, while the amine-activated surface (Figure 26A) demonstrates a low level of nonspecific interaction with the anti-biotin IgG at high concentrations. The NHS-PEG-Biotin surface (Figure 26C) clearly demonstrates strong specific interaction with the anti-biotin IgG-providing strong PWV shifts in proportion to the concentration of exposed anti-biotin IgG.

Figure 27 shows the PWV shift magnitudes after 20 minutes from Figure 26C plotted as a function of anti-biotin IgG concentration in Figure 26. A roughly linear correlation between the IgG concentration and the measured PWV shift is observed, and the lowest concentration IgG solution (1.25 mg/ml, 8.33 nM) is clearly measurable over the negative control PBS solution. Figure 28 shows the results of a cell morphology assay utilizing chondrocyte cells grown on the colorimetric resonant reflectance optical biosensor. The cells were observed to remain attached to the surface of the biosensor throughout the assay; the observed decrease in PWV upon addition of 2mg/ml trypsin to the biosensor wells containing the chondrocyte cells indicates a change in chondrocyte cell morphology. Figure 29 shows the results of a cell adhesion assay using kidney tumor cells. Trypsin was added to six biosensor wells containing kidney tumor cells grown on the surface of the biosensor. Two wells were utilized as replicate samples for each of the three trypsin concentrations. Upon addition of the trypsin, a decrease in PWV is observed indicating the detachment of the cells from the surface of the sensor. Figure 30 shows an example of a system for angular scanning of a biosensor. Figure 31 shows an example of a biosensor used as a microarray. Figure 32A-B shows two biosensor formats that can incorporate a colorimetric resonant reflectance biosensor. Figure 32A shows a biosensor that is incorporated into a microtiter plate. Figure 32B shows a biosensor in a microarray slide format. Figure 33 shows an array of arrays concept for using a biosensor platform to perform assays with higher density and throughput. Figure 34A-B. Figure 34A shows a measure resonant wavelength shift caused by attachment of a strepavidin receptor layer and subsequent detection of a biotinylated IgG. Figure 34B shows a schematic demonstration of molecules bound to biosensor. Figure 35A-B. Figure 35 A shows the spotting of rabbit, chicken, goat, and human IgG on a colorimetric resonant reflectance biosensor microarray. Figure 35B shows the result of flowing anti-human-IgG over the sensor surface, indicating greater binding between the human-IgG and the anti-human-IgG. Figure 36A-B. With Poly-T immobilized on the sensor surface, Figure 36A shows the different degrees of hybridization affinities between the immobilized oligonucleotides with Poly-T, Poly- A, and T7-promoter. Figure 36-B shows the endpoint data with error bars. Figure 37 shows an example of the specificity with which protein-DNA interactions, in this case between T7-promoter DNA and T7 RNA polymerase, can be detected. Figure 38 shows a schematic diagram of at cell-protein interaction assay. Figure 39 shows the results from a cell-protein interaction assay. DETAILED DESCRIPTION OF THE INVENTION A colorimetric resonant reflectance optical biosensor allows biochemical interactions to be measured on the biosensor's surface without the use of fluorescent tags, colorimetric labels or any other type of tag or label. A biosensor surface contains an optical structure that, when illuminated with collimated white light, is designed to reflect only a narrow band of wavelengths. The narrow wavelength band is described as a wavelength "peak." The "peak wavelength value" (PWV) changes when materials, such as biological materials, are deposited or removed from the biosensor surface. A readout instrument is used to illuminate distinct locations on a biosensor surface with collimated white light, and to collect collimated reflected light. The collected light is gathered into a wavelength spectrometer for determination of PWV. A biosensor structure can be incorporated into standard disposable laboratory items such as microtiter plates by bonding the structure (biosensor side up) into the bottom of a bottomless microtiter plate cartridge. Incorporation of a biosensor into common laboratory format cartridges is desirable for compatibility with existing microtiter plate handling equipment such as mixers, incubators, and liquid dispensing equipment. The functional advantages of each of the assay methods defined in this disclosure arise from the properties of a colorimetric resonant reflectance biosensor. First, biochemical interactions are measured without the use of labels. Second, many interactions can be monitored simultaneously. Third, the biosensor is incorporated into a standard microtiter plate for isolation and liquid containment of parallel assays. For the majority of assays currently performed for genomics, proteomics, pharmaceutical compound screening, and clinical diagnostic applications, fluorescent or colorimetric chemical labels are commonly attached to the molecules under study so they may be readily visualized. Because attachment of a label substantially increases assay complexity and possibly alters the functionality of molecules through conformational modification or epitope blocking, various label-free biosensor technologies have emerged. Label-free detection phenomenologies include measuring changes in mass, microwave transmission line characteristics, microcantilever deflection, or optical density upon a surface that is activated with a receptor molecule with high affinity for a detected molecule. The widespread commercial acceptance of label-free biosensor technologies has been limited by their ability to provide high detection sensitivity and high detection parallelism in a format that is inexpensive to manufacture and package. For example, biosensors fabricated upon semiconductor or glass wafers in batch photolithography, etch and deposition processes are costly to produce and package if the biosensor area is to be large enough to contain large numbers of parallel assays. Similarly, the requirement of making electrical connections to individual biosensors in an array poses difficult challenges in terms of package cost and compatibility with exposure of the biosensor to fluids. Definitions

Colorimetric resonant reflectance optical biosensor:

"Colorimetric resonant reflectance optical biosensors," alternatively referred to herein as biosensors, are defined herein as subwavelength structured surface (SWS) biosensors and surface-relief volume diffractive (SRVD) biosensors. See, e.g., U.S. Application 10/059,060 entitled "Resonant Reflection Microarray" and U.S. Ser. No. 10/180,374, and U.S. Ser. No. 10/180,647.

Entire Specific Binding Substance:

"Entire specific binding substance," as used herein, refers to substantially the entirety of a molecule of interest, such that, for example, the cleavage of substantially an entire specific binding substance from the surface of a colorimetric resonant reflectance optical biosensor yields the substantially complete, native specific binding substance.

Microtiter Plate:

"Microtiter plate," as used herein, is defined as a microtiter or multiwell plate of 2, 6, 8, 24, 48, 96, 384, 1536 or 3456 well formats, or any other number of wells.

Test Reagent:

"Test reagent," as used herein, is defined as any enzyme or chemical compound and solutions thereof. Non-limiting examples of enzymes are proteases, lipases, nucleases, lyases, peptidases, hydrolases, ligases, kinases and phosphatases. In addition to the enzymes, chemical compounds and solutions thereof, "test reagent" also refers to buffer blanks thereof. A buffer blank refers to reagents or solutions identical in composition to those added to the other recited test reagents, with the enzyme component omitted. Semi-Permeable Internal Sleeve:

A "semi-permeable internal sleeve," alternatively referred to as "insert" or "sleeve" herein, is defined as a porous material that is capable of supporting cell growth. A semi-permeable internal sleeve is permeable to proteins or other molecules secreted, shed or otherwise ejected from the cell grown on the sleeve surface but impermeable to a whole cell. A semi-permeable internal sleeve is generally held a short distance from the surface of a biosensor to which specific binding substances are bound or the growth media or buffer on the surface of a biosensor such that free diffusion of the secreted, shed or otherwise ejected moieties can occur through the sleeve. A semi-permeable internal sleeve can reside on any kind of colorimetric resonant reflectance optical biosensor, as defined above, within or without a well of a microtiter plate.

A semi-permeable internal sleeve that is "held in contact" with a surface of a biosensor or the surface of growth media or buffer on the surface of a biosensor is defined herein as (1) being positioned such that the sleeve is in close proximity to, but not in direct physical contact with the surface of the biosensor; (2) being positioned such that the sleeve is in physical contact with the surface of the buffer or growth media that is positioned on the biosensor surface; or (3) being positioned or connected in any manner such that diffusion of molecules secreted, shed or otherwise ejected from the cells through the semi-permeable internal sleeve is facilitated and, preferably, unhindered. "Held in contact" is also referred to as sitting or fitting "adjacent to the biosensor surface."

The types of material used as semi-permeable internal sleeve can be, for example, polyethylene terephthalate (PET) or polytetrafluoroethylene (PTFE) such as the material used within commercially available cell culture inserts (BD Falcon, Millipore).

Inhibition activity: "Inhibition activity" is defined herein as the ability of a molecule or compound to slow or stop another molecule from carrying out catalytic activity. For example, a compound that has inhibition activity of a protease inhibits the protease from cleaving a protein. Such inhibition activity is carried out "against" the catalytic molecule. "Inhibition activity" also means the ability of a molecule or compound to substantially inhibit or partially inhibit the binding of a binding partner to a specific binding substance.

Nucleic acid: "Nucleic acid" is defined herein as single or double stranded polymers of natural or non-natural nucleotides or derivatives thereof, linked by 3',5' phosphodiester linkages.

Ohgonucleotide: "Oligonucleotide" is defined herein as a single or double stranded polymer sequence of natural or non-natural nucleotides or derivatives thereof joined by phosphodiester bonds. "Oligonucleotide" generally refers to short polynucleotides of a length approximately 20 bases or less, beyond which they are preferentially referred to a polynucleotides.

Protein: "Protein" is defined herein as a linear polymer of natural or non-natural amino acids or derivatives thereof joined by peptide bonds in a specific sequence.

Peptide: "Peptide" is defined herein as any of a class of molecules that hydrolyze into amino acids and form the basic building blocks of proteins. Generally refers to a short polypeptide or protein fragment. Combinatorial chemical library: "Combinatorial chemical library" is defined herein as a diverse set of molecules resulting from the combination of their constituent building block materials in myriad ways. Cell membrane: "Cell membrane" is defined herein as the external, limiting lipid bilayer membrane of cells. Tissue: "Tissue" is defined herein as a group of cells, often of mixed types and usually held together by extracellular matrix, that perform a particular function. Also, in a more general sense, "tissue" can refer to the biological grouping of a cell type result from a common factor; for example, connective tissue, where the common feature is the function or epithelial tissue, where the common factor is the pattern of organization. Receptor: "Receptor" is defined herein as a membrane-bound or membrane-enclosed molecule that binds to, or responds to something more mobile (the ligand), with high specificity. Ligand: "Ligand" is defined herein as a molecule that binds to another; in normal usage a soluble molecule, such as a hormone or neurotransmitter, that binds to a receptor. Also analogous to "binding substance" herein. Cytokine:

"Cytokine" is defined herein as proteins released by cells and that affect the behavior of other cells. Similar to "hormone", but the term tends to be used as a generic word for interleukins, lymphokines and several related signaling molecules such as TNF and interferons.

Chemokine:

"Chemokine" is defined herein as small secreted proteins that stimulate chemotaxis of leucocytes.

Extracellular Matrix Material:

"Extracellular Matrix Material" is defined herein as any material produced by cells and secreted into the surrounding medium, but usually applied to the non- cellular portion of animal tissues.

Antigen:

"Antigen" is defined herein as a substance inducing an immune response. The antigenic determinant group is termed an epitope, and the epitope in the context of a carrier molecule (that can optionally be part of the same molecule, for example, botulism neurotoxin A, a single molecule, has tliree different epitopes. See Mullaney et al., Infect Immun 2001 Oct; 69(10): 6511-4) makes the carrier molecule active as an antigen. Usually antigens are foreign to the animal in which they produce immune reactions.

Polyclonal antibody: "Polyclonal antibody" is defined herein as an antibody produced by several clones of B-lymphocytes as would be the case in a whole animal. Usually refers to antibodies raised in immunized animals.

Claims

WE CLAIM:

1. A vessel comprising a colorimetric resonant reflectance optical biosensor, wherein the colorimetric resonant reflectance optical biosenseor comprises an internal surface of the vessel, wherein one or more specific binding substances are immobilized at two or more distinct locations on the internal surface of the vessel that comprises a colorimetric resonant reflectance optical biosensor.

2. The vessel of claim 1, wherein the vessel comprises a microtiter well, test tube, petri dish or microfluidic channel.

3. A microtiter plate comprising one or more microtiter wells, wherein a bottom surface of the one or more microtiter wells comprises a colorimetric resonant reflectance optical biosensor, wherein one or more specific binding substances are immobilized at two or more distinct locations on the bottom surface of each microtiter well.

4. A method of detecting binding of one or more types of cells to one or more specific binding substances comprising:

(a) applying the one or more types of cells to an internal surface of a vessel, wherein the internal surface of the vessel comprises a colorimetric resonant reflectance optical biosensor, wherein one or more specific binding substances are immobilized at two or more distinct locations on the internal surface of the vessel that comprises a colorimetric resonant reflectance optical biosensor;

(b) illuminating the vessel with light;

(c) detecting one or more peak wavelength values (PWV) for each distinct location; - 79 - wherein, if the one or more cells have bound to one or more specific binding substances, then the PWV is shifted at the distinct location to which the one or more cells are bound.

5. The method of claim 4, wherein the vessel is a microtiter well, microtiter plate, test tube, petri dish or microfluidic channel.

6. The method of claim 4, wherein the one or more specific binding substances are arranged in an array of distinct locations on the internal surface of the vessel that comprises a colorimetric resonant reflectance optical biosensor.

7. The method of claim 6, wherein the distinct locations define an array of spots of about 50-500 microns in diameter.

8. The method of claim 4, wherein the one or more specific binding substances are immobilized on the internal surface of the vessel that comprises a colorimetric resonant reflectance optical biosensor by a method selected from the group consisting of physical adsorption, chemical binding, electrochemical binding, electrostatic binding, hydrophobic binding and hydrophilic binding.

9. The method of claim 4, wherein the one or more specific binding substances are selected from the group consisting of nucleic acids, peptides, protein solutions, peptide solutions, single or double stranded DNA solutions, RNA solutions, RNA-DNA hybrid solutions, solutions containing compounds from a combinatorial chemical library, antigen, polyclonal antibody, monoclonal antibody, single chain antibody (scFv), F(ab) fragment, F(ab')₂ fragment, Fv fragment, small organic molecule, cell, virus, bacteria, polymer and biological sample.

10. A method of detecting binding of one or more cells to one or more specific binding substances comprising: - 80 - (a) immobilizing one or more specific binding substances to two or more distinct locations on an internal surface of a vessel, wherein the internal surface of the vessel comprises a colorimetric resonant reflectance optical biosensor;

(b) illuminating the vessel with light;

(c) detecting one or more peak wavelength values (PWVs) for each distinct location;

(d) applying one or more cells to the internal surface of the vessel;

(e) illuminating the vessel with light;

(f) detecting one or more peak wavelength values (PWVs) for each distinct location;

(g) comparing the PWVs of step (c) to the PWVs of step (f);

wherein, if the one or more cells have bound to one or more specific binding substances, then the PWV is shifted at the distinct location to which the cells are bound.

11. The method of claim 10, wherein the vessel is a microtiter well, microtiter plate, test tube, petri dish or microfluidic channel. - 81 -

12. The method of claim 10, wherein one or more specific binding substances are arranged in an array of distinct locations on the internal surface of the vessel that comprises a colorimetric resonant reflectance optical biosensor.

13. The method of claim 12, wherein the distinct locations define an array spot of about 50-500 microns in diameter.

14. The method of claim 10, wherein the one or more specific binding substances are immobilized on the internal surface of the vessel that comprises a colorimetric resonant reflectance optical biosensor by a method selected from the group consisting of physical adsorption, chemical binding, electrochemical binding, electrostatic binding, hydrophobic binding and hydrophilic binding.

15. The method of claim 10, wherein the specific binding substance is selected from the group consisting of nucleic acids, peptides, protein solutions, peptide solutions, single or double stranded DNA solutions, RNA solutions, RNA-DNA hybrid solutions, solutions containing compounds from a combinatorial chemical library, antigen, polyclonal antibody, monoclonal antibody, single chain antibody (scFv), F(ab) fragment, F(ab')₂ fragment, Fv fragment, small organic molecule, cell, virus, bacteria, polymer and biological sample.

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