High-density gold nanoparticles on multi-walled carbon nanotube films: a sensitive electrochemical nonenzymatic platform of glucose

In this study, a simple electrochemical method for grafting high-density gold nanoparticles (GNPs) on Congo red functionalised multi-walled carbon nanotube (MWNT–CR) films was reported. The GNP-decorated MWNT–CR composite (GNP–MWNT–CR), prepared by the constant potential deposition of GNPs on MWNT–CR films, had a compact and uniform nanostructure with a large surface area. Electrochemical characterisations showed that the GNP–MWNT–CR film exhibited excellent catalytic activity towards the direct electrochemical oxidation of glucose in basic media, with a much higher sensitivity than MWNT films, GNP films and GNP-coated MWNT films (GNP–MWNT). Under optimal working conditions, the oxidation current of glucose at the GNP–MWNT–CR film increased linearly with its concentration in the range 5.0 µM–37.0 mM with a low detection limit of 0.5 µM (S/N = 3). This glucose electrochemical sensor was applied to the determination of glucose in human serum samples and the results were satisfied.