Evaluation of a carbon nanotube-titanate nanotube nanocomposite as an electrochemical biosensor scaffold

Abstract

A significant aspect of this work is the development of a multi-wall carbon nanotube (MWCNT)-titanate nanotube (TNT) nanocomposite to serve as a biocompatible scaffold with high conductivity on a biosensor surface. Unlike other scaffolds consisting of MWCNTs alone or TNTs alone, the MWCNT–TNT nanocomposite synergistically provides excellent biocompatibility, good electrical conductivity, low electrochemical interferences and a high signal-to-noise ratio. For comparison, after characterising a scaffold consisting of MWCNTs alone, TNTs alone and a MWCNT–TNT nanocomposite using several spectroscopic techniques, the analytical performance of a horseradish peroxidase (HRP) electrochemical biosensor was evaluated using cyclic voltammetry and differential pulse voltammetry. The scaffold consisting of MWCNTs alone displayed a high background charging current, a low signal-to-noise ratio and distinct electrochemical interference from its surface functional groups. In contrast, the direct electrochemistry and the catalytic capability of HRP at MWCNT–TNT modified biosensors towards H2O2 was demonstrated to be ~51% and ~144% enhanced, respectively, compared to those at TNT modified biosensors. Meanwhile, MWCNT–TNT nanocomposite modified HRP biosensors also exhibited higher sensitivity (4.42μAmM−1) than TNT modified HRP biosensors (1.48μAmM−1). The above superior performance was attributed to the improved properties of MWCNT–TNT nanocomposite as biosensor scaffold compared to its two individual components by complementing each component and synergistically sustaining the characteristic features of each component.