Improvement in Sensing Performance of H2O2 Biosensor Electrodes through Modification of Anatase TiO2 Nanorods and Pretreatment of Electrochemical Reduction

Abstract

Electrochemical biosensors are essential health monitors that aid in the detection and diagnosis of diseases. In this research, anatase titanium dioxide (TiO 2 ) nanorods (TNR-A) were synthesized on a titanium (Ti) substrate in three stages, namely, hydrothermal, alkali, and heat treatments, and utilized as a modified electrode (TNR-A/Ti). The pretreatment of electrochemical reduction was adopted to increase the Ti 3+ amount in TiO 2 nanorod surfaces of the electrodes, thus improving electron transfer. The electrodes were characterized by X-ray diffractometry (XRD), fieldemission scanning electron microscopy (FESEM), and X-ray photoelectron spectroscopy (XPS). The electrodes after pretreatment (Ti 3+ -TNR-A/Ti) showed a better electrochemical response to hydrogen peroxide (H 2 O 2 ), indicating that pretreatment improves the performance of electrodes. The assembled biosensor electrode (Nafion/HRP/Ti 3+ -TNR-A/Ti) exhibited a sensitivity of 6096.4 µA•mM −1 •cm −2 , a detection limit of 0.008 µM, a linearity of 0.04-700 µM, and an apparent Michaelis-Menten constant K app M of 0.0027 µM, which are higher than those in previous research studies on TiO 2 or similarly nanostructured modified biosensor electrodes. This research could provide a potential competent method that can be used to modify electrodes for high-performance amperometric biosensors.