Direct voltammetry of copper, zinc-superoxide dismutase immobilized onto electrodeposited nickel oxide nanoparticles: fabrication of amperometric superoxide biosensor

چکیده مقاله

Direct electron transfer of immobilized copper, zinc-superoxide dismutase (SOD) onto electrodeposited nickeloxide
(NiOx) nanoparticle modified glassy carbon (GC) electrode displays a well defined redox process with formal
potential of 0.03 V in pH 7.4. Cyclic voltammetry was used for deposition of (NiOx) nanoparticles and immobilization
of SOD onto GC electrode. The surface coverage (G) and heterogeneous electron transfer rate constant (ks)
of immobilized SOD are 1.751011 molcm2 and 7.50.5 s1, respectively. The biosensor shows a fast amperometric
response (3 s) toward superoxide at a wide concentration range from 10 mM to 0.25 mM with sensitivity of
13.40 nAmM1cm2 and 12.40 nAmM1 cm2, detection limit of 2.66 and 3.1 mM based on anodically and cathodically
detection. This biosensor exhibits excellent stability, reproducibility and long life time.