ANALYTICAL AND BIOANALYTICAL CHEMISTRY, vol.383, no.6, pp.947-954, 2005 (SCI-Expanded)
A superoxide dismutase ( SOD) biosensor for determination of superoxide radicals has been developed by immobilization of superoxide dismutase within gelatin ( G) on a Pt electrode surface. The properties of the biosensor have been investigated and optimum conditions-enzyme concentration, glutaraldehyde concentration, and pH-were determined. The response of the G-SOD biosensor was proportional to O-2-(center dot-) concentration and the detection limit was 0.01 mmol L-1 at a signal-to-noise ratio of 3. The biosensor retained 89% and 60% of its sensitivity after use for three and four weeks, respectively. Immobilization of SOD on gelatin provides a biocompatible microenvironment around the enzyme and stabilizes the activity of the enzyme very efficiently. The superoxide dismutase biosensor was used to determine the antioxidant properties of acetylsalicylic acid-based drugs and the anti-radical activity of healthy and cancerous human brain tissues.