An array of poly-l-histidine functionalized multi-walled carbon nanotubes on 4-aminothiophenol self-assembled monolayer and the application for sensitively glucose sensing

Abstract

Novel approachs to functionalize carboxylated multi-walled carbon nanotubes (CMWCNTs) array with poly-l-histidine (PLH) on a self-assembled monolayer (SAM) of 4-aminothiophenol (4ATP) were developed for the first time. With help of π–π interaction and chelation of the side imidazole groups in poly-l-histidine, the array showed efficient electron transfer and mild biocompatibility. By immobilizing glucose oxidase (GOx) to AuNPs electrodeposited on the array, a high-powered glucose biosensor with excellent electrocatalytic performance was fabricated and applied for glucose determination in human serum samples. The prepared biosensor exhibited highly sensitive response to glucose under the operating voltage of 600 mV with sensitivity of 96.04 μA mM−1 cm−2, linear range of 0.005–6.5 mM, lowest detection limit (LOD) of 0.7 μΜ (S/N = 3) and Michaelis constant (KM) of 3.92 mM. Compared with other glucose sensors previously reported, this work showed higher sensitivity, lower detection limit and wider linear range. Furthermore, the developed array may provide a promising platform for various biosensors fabrication.