Electrochemical Characterization of Glucose Bioanodes Based on Tetramethylferrocene-Modified Linear Poly(ethylenimine)

Tetramethylferrocene-modified linear(polyethylenimine) (FcMe4-C3-LPEI) was cross-linked with ethylene glycol diglycidyl ether (EGDGE) in the presence of glucose oxidase (GOx) to form enzymatic glucose bioanodes capable of generating 1.034 ± 0.039 mA/cm2 with 3 mm glassy carbon electrodes and 15.1 ± 0.8  mA/cm2 with 0.5 × 0.5 cm carbon felt electrodes at 25 °C. FcMe4-C3-LPEI/GOx films were characterized by varying the amount of EGDGE, pH, and electrode material. The electrochemical potential was shown to vary with the amount of EGDGE used to cross-link the film, from 0.068 ± 0.016 V to 0.122 ± 0.003 V vs SCE using 4 mol% to 32 mol% EGDGE respectively. A similar trend occurred upon varying pH from 0.073 ± 0.004 V vs SCE at pH 4.0 to 0.118 ± 0.003 at pH 8.0. The optimized materials described herein have direct practical use as enzymatic bioanodes and as glucose biosensors.