Amperometric biosensor for in vivo glucose sensing based on glucose oxidase immobilized in a redox hydrogel.
A potentially implantable glucose sensor, based on glucose oxidase immobilized in a redox hydrogel, is considered. The redox hydrogel consisted of glucose oxidase immobilized in a cross-linkable poly(vinylpyridine) complex of [Os(bis-bipyridine)2Cl]+1/+2 that communicates electrically with the flavin adenine dinucleotide (FADH2) redox centres of the glucose oxidase. The implantable electrode consisted of a Teflon insulated platinum wire (0.25 mm diameter) which was coated at the tip with a cross-linked redox polymer/glucose oxidase film and covered with a thin layer of polycarbonate. In a three-electrode system at +400 mV (Ag/AgCl) the response to increasing glucose concentrations in isotonic phosphate buffer and human plasma was approximately 0.2-0.3 nA/mM, linear in the range between 0 and 15 mM glucose. No oxygen dependence was observed. To determine the in vivo performance, the electrode was implanted into the subcutaneous tissue of a dog. The sensor currents after an oral glucose load paralleled the plasma glucose measurements, with a time lag of 10 min. Three-day implantations in cultured cells showed that the electrode did not affect the growth and differentiation of cell monolayers.
Medical University of Lübeck, Department of Medicine, Germany.
B
B
Linke
W
W
Kerner
M
M
Kiwit
M
M
Pishko
A
A
Heller
D000818:Animals; D015374:Biosensing Techniques; D001786:Blood Glucose / Q000032:analysis*; D004285:Dogs; D004566:Electrodes; D004800:Enzymes, Immobilized; D005260:Female; D005949:Glucose Oxidase; D006367:HeLa Cells; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D011092:Polyethylene Glycols; D013242:Sterilization
D001786:Blood Glucose; D004800:Enzymes, Immobilized; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D011092:Polyethylene Glycols; D005949:Glucose Oxidase