Electrochemical detection of DNA hybridization based on three-dimensional ZnO nanowires/graphite hybrid microfiber structure

Abstract

In the present work, zinc oxide (ZnO) nanowire (NWs)/graphite microfiber hybrid electrodes were used for the detection of DNA hybridization. ZnO NWs were in-situ synthesized onto graphite fibers using the hydrothermal technique, and the result was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) as well as transmission electron microscope (TEM). An electrochemical sensor for the analysis of DNA hybridization was developed based on immobilizing DNA probes onto the ZnO NWs/graphite microfiber electrodes surface via electrostatic interaction. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS) were used to corroborate the fabrication of the sensor. Based on the results, ZnO NWs/graphite microfiber hybrid electrodes showed a great hybridization capacity for the determination of target DNA. A wide dynamic detection range from 1.0 × 10−14 M to 1.0 × 10−7 M with an ultralow detection limit of 3.3 × 10−15 M was achieved for detecting the target DNA. Moreover, it showed good selectivity and stability during the detection process.