ENHANCEMENT OF BIOSENSOR SENSITIVITY IN AQUEOUS AND ORGANIC-SOLVENTS USING A COMBINATION OF POLY(PYRROLE-AMMONIUM) AND POLY(PYRROLE-LACTOBIONAMIDE) FILMS AS HOST MATRICES

A new amphiphilic lactobionamide functionalized by a pyrrole group has been synthesized and electrochemically characterized. This functional ization has allowed the preparation of poly(pyrrole-lactobionamide) fi lms by oxidative electropolymerization in aqueous and organic electrol ytes. The electrochemical immobilization of glucose oxidase (GOx) and polyphenol oxidase (PPO) is carried out in polymeric 'bilayer' and 'tr ilayer' matrices based on poly(pyrrole-ammonium) and poly(pyrrole-lact obionamide) films. The amperometric response of GOx-based biosensors t o glucose in phosphate buffer was based on the oxidation at + 0.6 V vs . SCE of the generated H2O2. A marked enhancement of the biosensor sen sitivity (+ 60%) was observed for a trilayer matrix illustrating the b eneficial effect of the polymerized lactobionamide groups. The amperom etric response of PPO-based biosensors to catechol in chloroform was b ased on the reduction at - 0.25 V vs. SCE of the generated o-quinone. In the same way, the presence of poly(pyrrole-lactobionamide) as a pol ymeric additive induces a gnat enhancement of the biosensor sensitivit y (+ 350%) in anhydrous chloroform. (C) 1998 Elsevier Science S.A. All rights reserved.