Electrochemical characterization of enzyme electrodes mediated by ferrocene-containing acrylamide-acrylic acid copolymers

Electron transfer between a ferrocene-based redox polymer and active site of glucose oxidase (GOD) is demonstrated. Crosslinked copolymers of acrylamide and acrylic acid with 11 bonds side chains containing ferrocene at the ends were synthesized. GOD and this redox polymer were co-reticulated on a glassy carbon electrode surface using glutaraldehyde and bovine serum albumin (BSA). BSA-based immobilization was highly effective to stabilize electrochemical response of the redox polymer. Four copolymers with different ferrocene contents were prepared, and electron transfer process of each polymer was explored. The (DRCR)-C-1/2* values were estimated to be around 10(-9) mol cm(-2) s(-1/2), Electrochemical behavior of the redox polymer was found to be almost based on semi-infinite diffusion process. Thin hydrogel showed intermediate behavior between surface redox and diffusion-controlled processes. Catalytic electrochemistry of the enzyme electrodes was also investigated. The enzyme electrode with high ferrocene content revealed high catalytic current and low catalytic efficiency, i(cat)/i(redox).