Abstract

Carbon nanotube (CNT) can be considered as one of the best materials for enzyme nanobiosensor. In this study, we investigated comprehensively electron transfer properties in three kinds of carbon nanotubes for finding the best supporting material for comprising of the electrochemistry and electrocatalysis of enzymes in nano-dimension. Choline oxidase was selected as a sample enzyme for evaluating the performance of the electrodes. The enzyme was absorbed on modified SWCNT, MWCNT and Bamboo-like CNTs electrode in ionic liquid. Electron transfer and electroanalytical responses were investigated by Metrohm Autolab. Functionalization was studied by Raman spectroscopy and FTIR and also, the morphological evaluation was conducted by SEM. Raman spectroscopy showed that Bamboo-like CNTs had better properties in loading enzyme and other electrochemical properties for electron transfer. FTIR spectroscopy showed that Bamboo-like CNTs had high covalent binding on the surface wall of nanotubes. High loading of the enzyme was detected in Bamboo-like CNTs in comparison to two other nano-tubes by SEM. The electrochemical and amperometric response showed that Bamboo-like CNTs had a better response in different scan rates, wide linear range and detection limit. ChOx/RTIL/Bamboo-like CNTs/GC electrodes showed the high amounts of enzyme loading, high enzyme-substrate affinity, low detection limit, best sensitivity and wider linear range.