Electrochemical Sensing Based on Redox Mediation at Carbon Nanotube

• Published in: Analytical chemistry (Washington) Vol. 77; no. 13; p. 3960
• Main Authors: Zhang, Maogen, Gorski, Waldemar
• Format: Journal Article
• Language: English
• Published: Washington American Chemical Society 01-07-2005
• Subjects: Biochemistry; Dyes; Enzymes; Nanotubes; Sensors
• ISSN: 0003-2700; 1520-6882

An electrochemical sensing platform was developed based on the integration of redox mediators and carbon nanotubes (CNT) in a polymeric matrix. To demonstrate the concept, a redox mediator Azure dye (AZU) was covalently attached to polysaccharide chains of chitosan (CHIT) and interspersed with CNT to form composite films for the amperometric determination of Beta-nicotinamide adenine dinucleotide (NADH). The incorporation of CNT into CHIT-AZU matrix facilitated the AZU-mediated electrooxidation of NADH. In particular, CNT decreased the overpotential for the mediated process by an extra 0.30 V and amplified the NADH current by ~35 times (at -0.10 V) while reducing the response time from ~70 s for CHIT-AZU to ~5 s for CHIT-AZU/CNT films. These effects were discussed in terms of the AZU/CNT synergy, which improved charge propagation through the CHIT-AZU/CNT matrix. The concept of CNT-facilitated redox mediation in polymeric matrixes has a potential to be of general interest for expediting redox processes in electrochemical devices such as sensors, biosensors, and biological fuel cells and reactors. [PUBLICATION ABSTRACT]