Single-Walled Carbon Nanotubes Decorated with Dendrimer-Encapsulated Platinum Nanoparticles as Catalytic Immobilization Matrix for Amperometric Sensing of Glutamate

Abstract

Herein, we report the functional decoration of single-walled carbon nanotubes (swCNTs) with Pt dendrimer-encapsulated nanoparticles (Pt DENs) (dia. (1.78 +/- 0.18) nm) for the amperometric sensing of glutamate. The functional decoration of swCNTs was carried out via electrochemical grafting of Pt DENs onto swCNTs, and subsequent cross-linking of glutamate oxidase (GluOx) enzymes to the grafted Pt DENs on swCNT surfaces. The critical role of Pt DENs as catalytic immobilization matrix allowed both the immobilization of GluOx enzymes while maintaining the enzymatic activity of GluOx, and the electrocatalytic oxidation of H2O2 generated enzymatically in the presence of glutamate. Taking advantage of Pt DENs as catalytic immobilization matrix, the resulting swCNTs films, denoted as GluOx/Pt DEN/swCNTs, were applied as amperometric sensing platforms that display superior analytical characteristics, including sensitivity, selectivity, stability, and reproducibility, to the non-catalytic counterpart (i.e., GluOx/swCNTs), which led to the promising application of GluOx/Pt DEN/swCNTs to the practical analysis of glutamate in real samples.