A highly sensitive NADH biosensor using nitrogen doped graphene modified electrodes

摘要

The present work describes the fabrication of highly sensitive and selective beta-nicotinamide adenine dinucleotide (NADH) sensor using nitrogen doped graphene (NDG). NDG modified glassy carbon electrode (GCE) exhibits strong and stable electrocatalytic response towards NADH oxidation. A substantial (253 mV) decrease in the overpotential for NADH oxidation reaction (compared to GCE) is observed at NDG/GCE. NDG was prepared using hydrothermal procedure and characterized using spectroscopy and microscopy techniques. Furthermore, amperometric responses of NDG/GCE have high sensitivity towards NADH oxidation at lower oxidation potential and minimization of surface contamination. The fabricated NADH biosensor exhibited enhanced and reproducible sensitivity of 0.16 mu A/mu M (S/N = 3) with a response time of <3 s and the calculated limit of detection is 0.37 mu M. A linear dynamic range from 0.5-12 mu M was observed for the fabricated biosensor with a correlation coefficient (R-2) of 0.99. Moreover, the biosensor exhibited strong stability after prolonged usage. The oxidation peak potential at the NDG/GCE remained unchanged even after 15 days, with minimum surface contamination. Therefore, NDG materials are found useful and promising candidates for NADH detection and are attractive for dehydrogenase based biosensor. (C) 2016 Elsevier B.V. All rights reserved.