Biosensor

Abstract

In a biosensor comprising an electrically insulating base plate, an electrode system including a working electrode and a counter electrode formed on the base plate, and a reaction layer formed on or in the vicinity of the electrode system, at least surface of the reaction layer is made porous, so as to provide a biosensor of good response characteristic in which a reaction layer containing an enzyme dissolves quickly into a small amount of a sample solution and the enzyme reaction is effectively utilized.

1 . A biosensor comprising an electrically insulating base plate, an electrode system including a working electrode and a counter electrode formed on the base plate, and a reaction layer formed on or in the vicinity of the electrode system, at least a surface of the reaction layer being porous.  
     
     
         2 . The biosensor according to  claim 1 , wherein the reaction layer contains at least an enzyme and an aggregate of fine particles having an average diameter of not smaller than 0.1 μm and not larger than 1 μm.  
     
     
         3 . The biosensor according to  claim 1 , wherein the fine particles are made of a material selected from the group consisting of a polymer compound, ceramic, glass, diamond and carbon.  
     
     
         4 . The biosensor according to  claim 1 , wherein the reaction layer further contains an electron mediator.  
     
     
         5 . The biosensor according to  claim 1 , wherein a layer containing an electron mediator is formed in the vicinity of the reaction layer.  
     
     
         6 . The biosensor according to  claim 1 , wherein the reaction layer contains cholesterol esterase, a surfactant and at least one of cholesterol oxidase and cholesterol dehydrogenase, and a layer containing an electron mediator is formed in the vicinity of the reaction layer.