Dendritic platinum-decorated gold nanoparticles for non-enzymatic glucose biosensing

A bimetallic amperometric sensor comprising a dendritic Pt shell formed on rod-shaped Au cores (Au_rod@Pt) for the rapid estimation of glucose by direct electro-oxidation under physiological conditions is reported. The materials were characterized by XRD, TEM, UV-vis, and cyclic voltammetry. The sensor was constructed by immobilizing Au_rod@Pt bimetallic nanoparticles, in a Nafion film, on a glassy carbon electrode (Nafion/Au_rod@Pt/GCE). The results showed that Au_rod@Pt nanoparticles provided significantly higher sensitivity compared to dendritic Pt. X-ray absorption spectroscopy and X-ray photoelectron spectroscopy suggested that electron transfer, from the Au core to dendritic Pt, resulted in significant enhancement of electrocatalytic activity, due to reduction in Pt absorption of glucose oxidation intermediates and Cl^- ions. In addition, Nafion/Au_rod@Pt/GCE was found to exhibit a low working potential, fast amperometric response, high sensitivity, good reproducibility, good long term stability, and a high specificity to glucose with negligible interference from uric acid, ascorbic acid, acetamidophenol, or chloride ions.