Patent ID: 8101423

Claim:
A method of detecting binding of one or more specific binding substances to their respective binding partners comprising: (a) illuminating a biosensor with light and detecting a first peak wavelength value (PWV), wherein the biosensor comprises: (i) a two-dimensional grating; (ii) a substrate that supports the two-dimensional grating; wherein the refractive index of the two-dimensional grating is greater than the refractive index of the substrate; and (iii) one or more specific binding substances immobilized on the surface of the two-dimensional grating opposite of the substrate; wherein the one or more specific binding substances do not comprise detection labels, wherein when the biosensor is illuminated a resonant grating effect is produced on a reflected radiation spectrum, and wherein the depth and cross-sectional period of the two-dimensional grating are less than the wavelength of the resonant grating effect; (b) applying one or more binding partners to the biosensor, wherein the binding partners do not comprise detection labels; and (c) illuminating the biosensor with light and detecting a second PWV; wherein, if the one or more specific binding substances have bound to their respective binding partners, then the second PWV is shifted as compared to the first PWV.