ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Direct electrochemistry and electrocatalysis of horseradish peroxidase immobilized in hyaluronic acid and single walled carbon nanotubes composite film

Qi Wang and Jianbin Zheng

School of Science, Xidian University, 710071 Xi’an, China

E-mail: qwang@mail.xidian.edu.cn

Abstract: Direct electrochemistry and electrocatalysis of horseradish peroxidase (HRP) immobilized on a hyaluronic acid (HA)-single walled carbon nanotubes (SCNs) composite film coated glassy carbon electrode (GCE) was studied for the first time. HRP entrapped in the SCNs-HA composite film exhibited a pair of well-defined, quasi-reversible cyclic voltammetric peaks in a 0.1 M phosphate buffer solution (pH 7.0). Formal potential vs. standard calomel electrode (E°′) was −0.232 V, and E°′ was linearly dependent on the solution pH indicating that the electron transfer was proton-coupled. The current is linearly dependent on the scan rate, indicating that the direct electrochemistry of HRP in that case is a surface-controlled electrode process. UV-VIS spectrum suggested HRP retained its original conformation in the SCNs-HA film. Immobilized HRP showed excellent electrocatalysis in the reduction of hydrogen peroxide (H2O2).

Keywords: horseradish peroxidase - single walled carbon nanotubes - hyaluronic acid - direct electrochemistry - electrocatalysis

Full paper is available at www.springerlink.com.

DOI: 10.2478/s11696-010-0053-3

Chemical Papers 64 (5) 566–572 (2010)