Biosensor

Abstract

In a biosensor that detects introduction of a sample liquid into an analyte feed passage using a detecting electrode, a means of improving accuracy of detection is provided. The biosensor has: an electrode system including measuring electrode ( 2 ), counter electrode ( 3 ), and detecting electrode ( 4 ) on first electrically insulated board ( 1 ); analyte feed passage ( 7 ) for introducing the sample liquid; and reagent layer ( 5 ) used for quantifying a substrate contained in the sample liquid. The means is characterized in that detecting electrode ( 4 ) is spaced from measuring electrode ( 2 ) by a distance sufficient for the sample liquid to sufficiently cover measuring electrode ( 2 ) before the sample liquid reaches detecting electrode ( 4 ).

1 . A biosensor for quantifying a substrate contained in a sample liquid comprising: 
 a first electrically insulated board and a second electrically insulated board;    an electrode system having at least a measuring electrode, a counter electrode, and a detecting electrode;    an analyte feed passage for introducing the sample liquid over said electrode system; and    a reagent used for quantifying the substrate contained in the sample liquid;    wherein said electrode system, said analyte feed passage, and said reagent exist between said first electrically insulated board and said second electrically insulated board;    wherein said electrode system is formed on one of all and part of an inner surface of at least one of said first electrically insulated board and said second electrically insulated board; and    wherein said detecting electrode is spaced from said measuring electrode by a distance sufficient for the sample liquid to sufficiently cover said measuring electrode before the sample liquid reaches said detecting electrode.    
     
     
         2 . The biosensor as set forth in  claim 1 , wherein said detecting electrode is shaped to project so that a central portion thereof is positioned nearest to said measuring electrode in said analyte feed passage.  
     
     
         3 . The biosensor as set forth in  claim 1 , wherein said detecting electrode is shaped so that a central portion thereof is positioned nearest to said measuring electrode and both edges thereof are positioned farther to said measuring electrode than the central portion in said analyte feed passage.  
     
     
         4 . The biosensor as set forth in  claim 1 , wherein said detecting electrode is shaped to project in a direction of an inlet of said analyte feed passage in a central position within said analyte feed passage.  
     
     
         5 . The biosensor as set forth in any one of claims  2  through  4 , wherein said detecting electrode positioned within said analyte feed passage has one of a V-shape, a U-shape, and a convex shape.  
     
     
         6 . The biosensor as set forth in any one of claims  1  through  5 , wherein said analyte feed passage has a width ranging from 0.5 to 2.0 mm.  
     
     
         7 . The biosensor as set forth in any one of claims  1  through  6 , wherein said analyte feed passage has a height ranging from 0.05 to 0.3 mm.  
     
     
         8 . The biosensor as set forth in any one of claims  1  through  7 , wherein said electrode system is divided by providing a slit in an electrically conductive layer formed on one of all and part of an inner surface of at least one of said first electrically insulated board and said second electrically insulated board.  
     
     
         9 . The biosensor as set forth in  claim 8 , wherein said slit is formed by machining the electrically conductive layer using laser.  
     
     
         10 . The biosensor as set forth in any one of claims  1  through  9 , wherein an air vent in communication with said analyte feed passage is formed.