Abstract
Direct electrochemistry of glucose oxidase (GOx) at an electrochemically reduced graphene oxide-multiwalled carbon nanotubes hybrid (ERGO-MWCNT) modified glassy carbon electrode (GCE) has been reported. The pi-pi stacking interaction operating between the MWCNT and graphene oxide (GO) has been revealed by UV-Vis absorption spectroscopy. GOx was well immobilized onto the ERGO-MWCNT hybrid film, as a result direct electrochemistry of GOx has been achieved. Compared with pristine MWCNT, 2.1 fold higher peak current and very low peak to peak separation (Delta E-p) of 26 mV were observed at the hybrid film, demonstrating faster electron transfer between GOx and the modified electrode surface. Moreover, the modified film exhibited high electrocatalytic activity towards glucose via reductive detection of oxygen consumption and in the presence of mediator. The proposed biosensor exhibits low detection limit of 4.7 mu M with wide linear range of 0.01-6.5 mM and acquires excellent storage and operational stabilities. The accurate glucose determination in human blood serum and good recoveries achieved in spiked urine samples revealed their great potential in the practical applications. (C) 2012 Elsevier B.V. All rights reserved.