A Novel Nanoscale Electrode for Biosensing

Abstract

Nanoscale electrodes are becoming increasingly popular in Scanning Electrochemical Microscopy (SECM) due to their unique inherent properties. However, their preparation with current methods is laborious and not cost-effective, hindering the effective use of SECM in nanoscale detection and imaging. We have developed a novel and cost-effective nanoscale SECM electrode preparation method with electrochemically grown gold nanowires. Our method allows simple diameter tuning of nanowires and their direct interfacing with tungsten wires, enabling facile electrode preparation. The method is very cost-efficient as salt solutions of target noble metals are used in growing nanowires directly from tapered tungsten wires. The selective detection of target molecule is achieved by attaching DNA aptamers on the electrode surface. DNA aptamers are terminated with Methylene Blue redox molecules and an electronic signal is recorded with standard voltammetry due to target induced conformal change in the aptamers. The aptamer-based nanowire electrodes were successfully utilized in the detection of picomolar concentration ATP molecules.