Electrochemical sensing based on redox mediation at carbon nanotubes.
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 approximately 35 times (at -0.10 V) while reducing the response time from approximately 70 s for CHIT-AZU to approximately 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.
Zhang
Maogen
M
Department of Chemistry, University of Texas at San Antonio, San Antonio, Texas 78249, USA.
Gorski
Waldemar
W
D001399:Azure Stains / Q000737:chemistry; D048271:Chitosan / Q000737:chemistry; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods*; D037742:Nanotubes, Carbon / Q000737:chemistry*; D010084:Oxidation-Reduction
D001399:Azure Stains; D037742:Nanotubes, Carbon; D048271:Chitosan; C045363:Azure C