Amperometric glucose biosensor based on electroconductive hydrogels

Fabrication of an enzyme amperometric biosensor for glucose via electropolymerization of pyrrole in the presence of glucose oxidase onto a hydrogel coated platinum electrode is hereby established as a viable biotransducer fabrication method. Platinum micro- (φ=25 mm) and macro- (φ=100 μm) electrodes were electrochemically activated and chemically modified with 3-aminopropyl-trimethoxysilane (APTMS), functionalized with acryloyl(polyethyleneglycol)-N-hydroxysuccinamide (ACRL-PEG-NHS), dipped into a polyHEMA based hydrogel cocktail and UV cross-linked. Electropolymerization of Py in the presence of GOx produced glucose responsive biotransducers that showed; (i) a 4-fold reduction in sensitivity compared with directly electropolymerized PPy films, (ii) an electropolymerization charge density dependence of biotransducer sensitivity and enzyme activity that was maximal at 1.0 mC/cm² with an apparent K_M of 33 mM, (iii) interference screening of ascorbic acid and (iv) a temporal increase in sensitivity with storage over a 17 days period. This method has the ability to precisely and quantitatively add enzyme catalytic bioactivity to metal or semiconductor biointerfaces for applications in biosensors, bioelectronics and bionics.