Patent ID: 8372630

Claim:
A method of manufacturing an optical glucose sensor chip, comprising: preparing a glucose sensing membrane-forming coating solution that comprises: a color reagent substrate; a first enzyme that oxidizes or reduces glucose; a second enzyme that generates a material which makes the color reagent substrate exhibit color by a reaction with a product obtained by the oxidation or reduction of glucose; a nonionic cellulose derivative; an ionic polymer selected from the group consisting of a polymer containing a cationic group which is an amino group, guanidino group or biguanide group, and a polymer containing an anionic group which is a phosphate group or sulfonate group; and a buffer; by using any of: (a) a method in which either the first enzyme or the second enzyme is mixed in advance with an aqueous solution containing the ionic polymer and the buffer, and the mixed solution is added to and mixed with the other enzyme, the color reagent substrate and the nonionic cellulose derivative; (b) a method in which the first and second enzymes are respectively mixed in advance with an aqueous solution containing the ionic polymer and the buffer, and the respective prepared mixed solutions are added to and mixed with the color reagent substrate and the nonionic cellulose derivative; or (c) a method in which both the first and second enzymes are mixed in advance with an aqueous solution containing the ionic polymer and the buffer, and the prepared mixed solution is added to and mixed with the color reagent substrate and the nonionic cellulose derivative; forming a pair of optical elements on a substrate for introducing light into the substrate and for emitting the light from the substrate; and applying the glucose sensing membrane-forming coating solution to a substrate area positioned between the optical elements, followed by drying to form a glucose sensing membrane.