title: Optical biosensor assay (OBA).
abstract: We describe a new biosensor immunoassay involving optical diffraction to detect clinically important analytes in human body fluids. A silicon wafer is used as a support for immobilization of antigen or antibody. The protein-coated surface is illuminated through a photo mask to create distinct periodic areas of active and inactive protein. When the surface is incubated with a positive sample, antigen-antibody binding occurs only on the active areas. Upon illumination with a light source such as a laser, the resulting biological diffraction grating diffracts the light. A negative sample does not result in diffraction because no antigen-antibody binding occurs to create the diffraction grating. The presence or absence of a diffraction signal differentiates between positive and negative samples, and the intensity of the signal provides a quantitative measure of the analyte concentration. The technique is demonstrated with a quantitative assay of choriogonadotropin in serum.
authors.affiliation: Adeza Biomedical Corp., Sunnyvale, CA 94089.
authors.forename: Y G
authors.initials: YG
authors.lastname: Tsay
authors.forename: C I
authors.initials: CI
authors.lastname: Lin
authors.forename: J
authors.initials: J
authors.lastname: Lee
authors.forename: E K
authors.initials: EK
authors.lastname: Gustafson
authors.forename: R
authors.initials: R
authors.lastname: Appelqvist
authors.forename: P
authors.initials: P
authors.lastname: Magginetti
authors.forename: R
authors.initials: R
authors.lastname: Norton
authors.forename: N
authors.initials: N
authors.lastname: Teng
authors.forename: D
authors.initials: D
authors.lastname: Charlton
mesh_terms: D015374:Biosensing Techniques; D001826:Body Fluids / Q000737:chemistry; D006063:Chorionic Gonadotropin / Q000032:analysis / Q000276:immunology; D006801:Humans; D007118:Immunoassay; D055095:Optics and Photonics
chemical_list: D006063:Chorionic Gonadotropin