"Wired" enzyme electrodes for amperometric determination of glucose or lactate in the presence of interfering substances.
Glucose oxidase (GOX) or lactate oxidase (LOX) were immobilized in an osmium-based three-dimensional redox hydrogel that electrically connected the enzyme's redox centers to electrodes. The enzyme "wiring" hydrogel was formed by cross-linking poly(1-vinylimidazole) (PVI) complexed with Os-(4,4'-dimethylbpy)2Cl (termed PVI15-dmeOs) with poly(ethylene glycol) diglycidyl ether (peg). Glucose and lactate sensors exhibited typical limiting current densities of 250 and 500 microA/cm2, respectively. When the electrodes were poised at 200 mV (SCE), the currents resulting from electrooxidation of ascorbate, urate, acetaminophen, and L-cysteine were negligible. When a Nafion film was employed, the linear range was extended from 6 to 30 mM glucose and from 4 to 7 mM lactate. The redox potential of the gel-forming polymer was 95 mV (SCE). Glucose and lactate measurements performed in bovine calf serum correlated well with a substrate calibration in phosphate buffer.
Ohara
T J
TJ
Department of Chemical Engineering, University of Texas at Austin 78712-1062.
Rajagopalan
R
R
Heller
A
A
D000818:Animals; D015374:Biosensing Techniques; D001786:Blood Glucose / Q000032:analysis; D002138:Calibration; D002417:Cattle; D004800:Enzymes, Immobilized; D005947:Glucose / Q000032:analysis*; D005949:Glucose Oxidase / Q000378:metabolism; D007773:Lactates / Q000032:analysis* / Q000097:blood; D019344:Lactic Acid; D006899:Mixed Function Oxygenases / Q000378:metabolism; D010084:Oxidation-Reduction
D001786:Blood Glucose; D004800:Enzymes, Immobilized; D007773:Lactates; D019344:Lactic Acid; D006899:Mixed Function Oxygenases; D005949:Glucose Oxidase; C021497:lactate 2-monooxygenase; D005947:Glucose