Bioactive electroconductive hydrogels yield novel biotransducers for glucose

A class of bioactive, stimuli-responsive co-joined interpenetrating networks of inherently conductive polymers and highly hydrated hydrogels are being developed for implantable biodevice interfaces and for electric field induced release of elutable drugs. A novel microfabricated multidisc electrode array biotransducer intended for trauma management has been coated with poly(HEMA)-polypyrrole and characterized by cyclic voltammetry and chronoamperometry using ferrocene monocarboxylic acid (FcCOOH) as a probe molecule. Electrodeposition of polypyrrole (700 mV vs. Ag/AgCl) to 100 mC/cm ² onto the hydrogel coated microdisc electrode array resulted in large and unstable background currents relative to uncoated electrodes. Overoxidation of polypyrrole (0-1.2 V vs. Ag/AgCl, 20 cylces, 100 mV/s) eliminates background current. Dose-response curves with FcCOOH showed that the transducer has good reproducibility with molecules of facile electrochemical properties. Polypyrrole provides interference screening of endogenous interferents in biosensor applications with a 12:1 rejection ratio. GOx was immobilized via electropolymerization of polypyrrole into hydrogel coated MDEA 5037s to yield biotransducers with sensitivity of 0.045 μA mM ^-1 cm ^-2. Changes to improve biotransducer sensitivity are proposed.