Patent ID: 7498145
Filing Date: 2009-03-03
Classification: G01N,Y10S

Abstract:
1. A method for measuring the concentration of an analyte, which comprises: (i) obtaining a sensor chip comprising: an optical waveguide layer configured to propagate a light within the layer by total reflection of the light, an antibody-immobilized layer, having an immobilized antibody, formed on at least a part of a surface of the optical waveguide layer, a frame member adhered on a surface of the optical waveguide layer, surrounding the antibody-immobilized layer, for constituting a cell, and a liquid-repelling film formed on a part of the optical waveguide layer except where a frame member is located, said film having a surface level higher than the antibody-immobilized layer and lower than the frame member to form a reaction hole that exposes at least one part of the antibody-immobilized layer; (ii) immobilizing the analyte and an enzyme-labeled antibody, which is labeled with a labeling enzyme, on the antibody-immobilized layer in the reaction hole of the sensor chip; (iii) precipitating a color-developed enzyme reaction product by allowing a coloring reagent and the labeling enzyme on the antibody-immobilized layer to react; (iv) reflecting totally a light impinged on the sensor chip from the outside at an interface between the optical waveguide layer and the antibody-immobilized layer; (v) detecting a change in reflection light intensity caused absorption of an evanescent wave by the color-developed enzyme reaction product at the antibody-immobilized layer; and (vi) measuring a concentration of the analyte based on the change of the reflection light intensity.