Enzymatic reagent inks for use in test strips having a predetermined calibration code
First Claim
1. An enzyme ink composition, comprising an enzyme capable of selectively recognizing glucose in a blood sample, a mediator, and a first and a second fumed silica, wherein the first fumed silica comprises a BET measured surface area of about 130 to 170 m2/g and a carbon content of about 0.8 to about 1.23 weight percent and the second fumed silica comprises a BET measured surface area of about 270 to 330 m2/g and a carbon content of about 1.4 to about 2.6 weight percent.
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Abstract
The invention provides an enzyme ink useful in test strips that provides a test strip bias, at the low and high glucose ends, falling within a desired target range. The ink of the invention permits an improved method for the production of single calibration code strip lots with good yields.
10 Citations
12 Claims
- 1. An enzyme ink composition, comprising an enzyme capable of selectively recognizing glucose in a blood sample, a mediator, and a first and a second fumed silica, wherein the first fumed silica comprises a BET measured surface area of about 130 to 170 m2/g and a carbon content of about 0.8 to about 1.23 weight percent and the second fumed silica comprises a BET measured surface area of about 270 to 330 m2/g and a carbon content of about 1.4 to about 2.6 weight percent.
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6. An enzyme ink, comprising about 0.3 percent by mass of an antifoam compound, about 0.6 percent by mass of polyvinyl alcohol, about 0.6 percent by mass citric acid, about 1.9 percent by mass trisodium citrate, about 0.6 percent by mass polyvinylpyrrolidone-vinyl acetate copolymer, about 3.27 percent by mass hydroxyethyl cellulose, about 3.6 percent by mass of a first fumed silica with a BET measured surface area of about 130 to 170 m2/g and a carbon content of about 0.8 to about 1.23 weight percent, about 1.3 percent by mass of a second fumed silica with a BET measured surface area of about 270 to 330 m2/g and a carbon content of about 1.4 to about 2.6 weight percent, about 0.03 percent by mass potassium hexacyanoferrate III, about 23 percent by mass of potassium ferricyanide;
- about 2.1 percent by mass glucose oxidase and about 62.4 percent by mass water.
- 7. A test strip comprising at least two co-planar electrodes, wherein at least one of the electrodes comprises an enzyme ink composition comprising an enzyme capable of selectively recognizing glucose in a blood sample, a mediator, and a first and a second fumed silica, wherein the first fumed silica comprises a BET measured surface area of about 130 to 170 m2/g and a carbon content of about 0.8 to about 1.23 weight percent and the second fumed silica comprises a BET measured surface area of about 270 to 330 m2/g and a carbon content of about 1.4 to about 2.6 weight percent.
Specification