Seed-mediated growth of platinum nanoparticles on carbon nanotubes for the fabrication of electrochemical biosensors

Abstract

Platinum nanoparticles (PtNPs) were prepared by seed-mediated growth method with Au nanoparticles (AuNPs) playing the role of seeds. Carbon nanotubes (CNTs) and AuNPs were first dropped onto the surface of glassy carbon (GC) electrode, and then the electrode was immersed into growth solution which contains H 2PtCl 6 and ascorbic acid. PtNPs were successfully grown onto the CNT surface due to the chemical reduction of Pt(IV). The electrode modified with AuNP seed/PtNP/CNT film displayed excellent electrochemical response to H 2O 2 at 0.45 V versus saturated calomel electrode (SCE) with sensitivity much larger than that of PtNP/CNT and AuNP seed/PtNP modified electrodes. Glucose oxidase was selected as a model enzyme and electrodeposited onto the AuNP seed/PtNP/CNT modified electrode in the presence of a detergent. The resulting biosensor enabled selective determination of glucose with high sensitivity of 4.49 μA mM −1, quick response time about 2 s, low-detection limit of 0.5 μM and wide linear range from 1 μM to 4 mM with a correlation coefficient 0.9998. Thus, the modified electrode proved to be a nice electrochemical biosensing platform for the fabrication of oxidase-based biosensors.