Guided Mode Resonant Filter Biosensor Using a Linear Grating Surface Structure

Abstract

Methods and compositions are provided for detecting biomolecular interactions. The use of labels is not required and the methods can be performed in a high-throughput manner. The invention also provides optical devices useful as narrow band filters.

1 . A biosensor comprising:
 (a) a grating layer comprising a one-dimensional or two-dimensional grating having a first surface, wherein the grating layer is comprised of a low refractive index material;   (b) an interfacial layer on the first surface of the grating layer;   (c) a high refractive index material layer on a surface of the interfacial layer opposite of the grating layer; and   (d) one or more specific binding substances immobilized on a surface of the high refractive index material layer opposite of the interfacial layer;   wherein, when the biosensor is illuminated a resonant grating effect is produced on the reflected radiation spectrum.   
     
     
         2 . The biosensor of  claim 1 , wherein the interfacial layer is comprised of a material selected from the group consisting of silicon oxide, silicon oxynitride, borosilicate glass, phosphosilicate glass, pyrex, glass, and a metal oxide. 
     
     
         3 . The biosensor of  claim 1 , wherein the interfacial layer is about 1 nm to about 200 nm thick. 
     
     
         4 . The biosensor of  claim 1 , wherein the one or more specific binding substances are detection label-free. 
     
     
         5 . The biosensor of  claim 1 , wherein, when the biosensor is illuminated a resonant grating effect is produced on a reflected radiation spectrum, and wherein the cross-sectional period of the grating layer is less than the wavelength of the resonant grating effect. 
     
     
         6 . The biosensor of  claim 1 , wherein the cross-sectional profile of the grating layer is triangular, sinusoidal, trapezoidal, rectangular, v-shaped, u-shaped, upside-down u-shaped, upside-down v-shaped, stepped or square. 
     
     
         7 . The biosensor of  claim 1 , wherein a narrow band of optical wavelengths is reflected from the biosensor when the biosensor is illuminated with a broad band of optical wavelengths. 
     
     
         8 . The biosensor of  claim 1 , wherein the low refractive index material comprises glass, plastic, polymer, or epoxy. 
     
     
         9 . The biosensor of  claim 1 , wherein the high refractive index material layer is zinc sulfide, titanium dioxide, indium tin oxide, tantalum oxide, or silicon nitride. 
     
     
         10 . The biosensor of  claim 1 , wherein the grating layer has a cross-sectional period of about 0.01 microns to about 1 micron and a depth of about 0.01 microns to about 1 micron. 
     
     
         11 . The biosensor of  claim 1 , wherein the one or more specific binding substances are arranged in an array of distinct locations. 
     
     
         12 . The biosensor of  claim 11 , wherein the distinct locations define a microarray spot of about 10 to 500 microns in diameter. 
     
     
         13 . The biosensor of  claim 1 , wherein the one or more specific binding substances are immobilized on the grating layer by physical adsorption or by chemical binding. 
     
     
         14 . The biosensor of  claim 1 , wherein the one or more specific binding substances are selected from the group consisting of nucleic acids, polypeptides, antigens, polyclonal antibodies, monoclonal antibodies, single chain antibodies (scFv), F(ab) fragments, F(ab) 2  fragments, Fv fragments, small organic molecules, cells, viruses, bacteria, polymers, peptide solutions, protein solutions, chemical compound library solutions, single-stranded DNA solutions, double-stranded DNA solutions, RNA solutions, and biological samples. 
     
     
         15 . The biosensor of  claim 14 , wherein the biological sample is selected from the group consisting of blood, plasma, serum, gastrointestinal secretions, homogenates of tissues or tumors, synovial fluid, feces, saliva, sputum, cyst fluid, amniotic fluid, cerebrospinal fluid, peritoneal fluid, lung lavage fluid, semen, lymphatic fluid, tears, and prostatic fluid. 
     
     
         16 . The biosensor of  claim 1 , wherein the biosensor is an internal surface of a liquid-containing vessel. 
     
     
         17 . The biosensor of  claim 16 , wherein the liquid-containing vessel is selected from the group consisting of a microtiter plate, a test tube, a petri dish and a microfluidic channel.