Controlled fabrication of glucose and catechol microbiosensors via electropolymerized biotinylated polypyrrole films

The functionalization of microelectrodes has been carried out by oxidative polymerization of a biotinyl pyrrole monomer in acetonitrile. The resulting biotinylated polymer was used for the sim-pie and reagentless anchoring of avidin and biotinylated enzymes via avidin-biotin bridges. Thus, the immob ilization of five layers of glucose oxidase was performed on various platin um electrodes (surfaces: 0.165 and 0.448 mm(2)). The amperometric response of the microbiosensors to glucose was recorded at 0.6 V vs Ag/AgCl and the analytical performances (sensitivity and I-max)were proportional to the mic roelectrode surface. In addition, the immobilization of four and seven laye rs of polyphenol oxidase on carbon fiber mi croelectrodes (diameter 8 mum) has led to amperometric biosensors for catechol exhibiting analytical chara cteristics proportional to the number of enzyme layers. Moreover, these two kinds of micro-biosensor present apparent K-M values similar to those dete rmined for the free enzymes in bulk solution.