Département de chimie moléculaire

Horseradish peroxidase (HRP) was immobilized on redox buckypapers followed by electropolymn. of pyrrole-modified Con A enabling the subsequent addnl. immobilization of the glycoprotein glucose oxidase (GOx). Biocatalytic buckypapers were formed using pyrene-modified 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) or bis-Pyr-ABTS, a redox mediator, as a cross-linker. ABTS-functionalized buckypaper enhances the electron transfer of the bioelectrocatalytic redn. of H2O2 by HRP. Since H2O2 is produced during glucose oxidn. by GOx in the presence of oxygen, the bienzymic GOx-HRP biocathode achieves the complete redn. of oxygen into water. A clearly improved performance of the biocathode was obtained by using an improved biocompatible immobilization strategy, enabling the prevention of enzyme loss while ensuring both diffusion of glucose and O2 and the local prodn. of H2O2. These freestanding flexible oxygen-reducing biocathodes can operate under physiol. conditions and show a high onset potential at 0.60 (±0.01) V. In the presence of glucose (5 mM), such biocathodes exhibit a stable c.d. output of 1.1 (±0.1) mA cm-2 at 0.1 V under continuous one-hour discharge. Furthermore, a marked increase in lifetime was obsd., the biocathode displaying 64{%} of its initial electrocatalytic activity after 15 days. [on SciFinder(R)]