Sensitive superoxide biosensor based on silicon carbide nanoparticles

Abstract

Direct electron transfer of immobilized superoxide dismutase (Cu, Zn-SOD) onto silicon carbide (SiC) nanoparticles displays a pair of well defined and nearly reversible redox peaks with formal potential (E°') of -0.03 V in pH 7.4. The heterogeneous electron transfer rate constant (ks) and surface coverage (Γ) of immobilized SOD are 11.0±0.4 s-1 and 1.42x10-11 mol cm-2. Biosensor shows fast amperometric response (3s) with sensitivity and detection limit of 1.416 nA μM-1, 1.66 μM, and 1.375 nA μM-1, 2.1 μM for cathodically or anodically detection of superoxide, respectively. This biosensor also exhibits good stability, reproducibility and long life-time. © 2010 Wiley-VCH Verlag GmbH&Co. KGaA, Weinheim.