Test sensors and methods of using the same

Abstract

A reagent composition containing GDH-PQQ as an enzyme-co-factor and screen-printed on working and counter electrodes of electrochemical biosensors, maintains activity of the enzyme reagents by proper selection of components. A preferred composition includes hydrophilic polymers, amorphous untreated silica, buffers, surfactants, and a mediator.

1 - 32 . (canceled) 
     
     
         33 . An electrochemical biosensor comprising:
 a substrate;   at least two electrodes disposed on the substrate;   a reagent composition deposited on the at least two electrodes, the composition comprising
 about 30 to about 200 mM of a buffer, 
 up to about 0.5 wt % of a surfactant, based on the total weight of the composition, 
 about 2 to about 10 wt % of a cellulose derivative, based on the total weight of the composition, 
 about 1 to about 6 wt % of amorphous untreated silica, based on the total weight of the composition, 
 about 10 to about 20 wt % of a mediator, based on the total weight of the composition, and 
 about 1 to about 8 units of an enzyme-cofactor for each milligram of the total weight of the composition, 
 wherein the composition has a viscosity of from about 60,000 to about 180,000 cps (mPa*s). 
   
     
     
         34 . The electrochemical biosensor of  claim 33  comprising about 50 to about 150 mM of the buffer. 
     
     
         35 . The electrochemical biosensor of  claim 33 , wherein the buffer is an acetate, citrate, or succinate buffer. 
     
     
         36 . The electrochemical biosensor of  claim 33 , further comprising about 5 to about 50 mM of CaCl 2 . 
     
     
         37 . The electrochemical biosensor of  claim 33 , wherein the surfactant is an alkyl aryl polyether alcohol. 
     
     
         38 . The electrochemical biosensor of  claim 33 , wherein the cellulose derivative is hydroxyethyl cellulose. 
     
     
         39 . The electrochemical biosensor of  claim 33 , wherein the mediator is potassium ferricyanide. 
     
     
         40 . The electrochemical biosensor of  claim 33 , wherein the enzyme is glucose dehydrogenase (GDH) and the co-factor is pyrrolo-quinoline quinone (PQQ). 
     
     
         41 . The electrochemical biosensor of  claim 33 , wherein the pH is between about 4.5 to about 6.5. 
     
     
         42 . An electrochemical biosensor comprising:
 a substrate;   at least two electrodes disposed on the substrate;   a reagent composition deposited on the at least two electrodes, the composition comprising
 about 30 to about 200 mM of a buffer, 
 up to about 0.5 wt % of a surfactant, based on the total weight of the composition, 
 about 2 to about 10 wt % of hydroxyethyl cellulose, based on the total weight of the composition, 
 about 1 to about 6 wt % of amorphous untreated silica, based on the total weight of the composition, 
 about 10 to about 20 wt % of a ferricyanide mediator, based on the total weight of the composition, and 
 about 1 to about 8 units of glucose dehydrogenase (GDH) and pyrrolo-quinoline quinone (PQQ) for each milligram of the total weight of the composition, 
 wherein the composition has a viscosity of from about 60,000 to about 180,000 cps (mPa*s). 
   
     
     
         43 . The electrochemical biosensor of  claim 42  comprising about 50 to about 150 mM of the buffer. 
     
     
         44 . The electrochemical biosensor of  claim 42 , further comprising about 5 to about 50 mM CaCl 2 . 
     
     
         45 . The electrochemical biosensor of  claim 42 , wherein the mediator is potassium ferricyanide. 
     
     
         46 . The electrochemical biosensor of  claim 42 , wherein the pH is between about 4.5 to about 6.5.