A Novel Nanoscale Scanning Electrochemical Microscope Electrode and Its Utilization as Aptamer Based Biosensor

A. Guver, P. Milas, M. Guy, V. Yigit, M.T. Sigindere, T. Yildirim, I. Unlu, K. Green, B. Ozturk
Morgan State University,
United States

Keywords: SECM, nanowire, nanoscale, electrode, aptamer, ATP


Ultramicroelectrodes (UMEs) have been the standard choice of electrodes in most Scanning Electrochemical Microscopy (SECM) experiments and their charge transfer kinetics have been well characterized. Nanoscale electrodes are becoming increasingly popular in 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, cost effective nanoscale SECM electrode preparation method with electrochemically grown gold and platinum nanowires. Our method enables 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 aptamer. The aptamer-based nanowire electrodes were successfully utilized in the detection of picomolar concentration ATP molecules. Results of high spatial resolution scanning images of single live astrocyte cells for detection ATP release sites will be presented.