TEST SENSORS AND METHODS OF USING THE SAME
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.