Label-Free High-Throughput Optical Technique for Detecting Biomolecular Interactions
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 method of detecting the binding of one or more specific binding substances to their respective binding partners comprising:
(a) applying one or more binding partners to a biosensor comprising: (i) a linear grating layer having a depth and a period comprised of a material having a high refractive index; (ii) a low refractive index material layer that supports the linear grating layer; and (iii) one or more specific binding substances immobilized on the surface of the linear grating layer opposite of the low refractive index material layer; wherein, when the biosensor is illuminated a resonant grating effect is produced on a transmitted radiation spectrum, and wherein the depth and the period of the linear grating layer are less than the wavelength of the resonant grating effect;
(b) illuminating the biosensor with light; and
(c) detecting a minimum in the spectrum of transmitted wavelength of light from the biosensor;
wherein, if the one or more specific binding substances have bound to their respective binding partners, then the minimum in the spectrum of transmitted wavelength of light is shifted.
2 . The method of claim 1 , wherein the one or more specific binding substances and their binding partners are detection label-free.
3 . The method of claim 1 , wherein the one or more binding partners comprise one or more tags comprising biotin, succinimidyl-6-[a-methyl-a-(2-pyridyl-dithio) toluamido] hexanoate (SMPT), dimethylpimelimidate (DMP), or histidine.
4 . The method of claim 3 , wherein the one or more tags are reacted with streptavidin, horseradish peroxidase, or streptavidin coated nanoparticles, before the step of illuminating the biosensor with light.
5 . The method of claim 1 , wherein the low refractive index material layer comprises glass, plastic, or epoxy.
6 . The method of claim 1 , wherein the linear grating layer is comprised of zinc sulfide, titanium dioxide, indium tin oxide, tantalum oxide, or silicon nitride.
7 . The method of claim 1 , wherein the one or more specific binding substances are arranged in an array of distinct locations on the linear grating layer.
8 . The method of claim 1 , wherein the amount of the one or more binding partners is determined.
9 . The method of claim 1 , wherein the biosensor is illuminated from its top surface or from its bottom surface.
10 . A detection system comprising:
(a) a biosensor comprising (i) a linear grating layer having a depth and a period comprised of a material having a high refractive index; (ii) a low refractive index material layer that supports the linear grating layer; and (iii) one or more specific binding substances immobilized on the surface of the linear grating layer opposite of the low refractive index material layer; wherein, when the biosensor is illuminated a resonant grating effect is produced on a transmitted radiation spectrum, and wherein the depth and the period of the linear grating layer is less than the wavelength of the resonant grating effect;
(b) a light source that directs light to the biosensor; and
(c) a detector that detects light transmitted through the biosensor.
11 . The detection system of claim 10 , wherein the low refractive index material layer comprises glass, plastic, or epoxy.
12 . The detection system of claim 10 , wherein the linear grating layer is comprised of zinc sulfide, titanium dioxide, indium tin oxide, tantalum oxide, or silicon nitride.
13 . The detection system of claim 10 , wherein the one or more specific binding substances are arranged in an array of distinct locations on the linear grating layer.
14 . The detection system of claim 10 , wherein the amount of the one or more binding partners is determined.
15 . The detection of claim 10 , wherein the light source illuminates the biosensor from its top surface or from its bottom surface.