Sensitive Superoxide Biosensor Based on Silicon Carbide Nanoparticles

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 (k_s) and surface coverage (Γ) of immobilized SOD are 11.0±0.4 s^?1 and 1.42×10^?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.