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.
Department of Chemistry, University of Texas at San Antonio, San Antonio, Texas 78249, USA.
Maogen
M
Zhang
Waldemar
W
Gorski
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