Electrochemical Biosensor Utilizing Nitrogen Incorporated Nanodiamond Ultra-Microelectrode Array

Abstract

A nitrogen incorporated nanodiamond ultra-microelectrode array was fabricated using silicon microfabrication technology and microwave PECVD process. 400 ultra-microelectrodes, which are arranged in a square array, project above the surrounding plane of the SiO2 insulation layer. Each ultra-microelectrode has a radius of 5µm and a spacing of 100µm, in order to avoid an overlap of individual diffusion layers. Dopamine (DA), which is an important catecholamine neurotransmitter, can be detected by the UMEA using steady state cyclic voltammetry with a linear dynamic range of 100µM-1mM. Even though Ascorbic acid (AA) interferes with DA detection under real physiological conditions, we are able to extract the calibration curve for different DA concentrations in the presence of 1mM AA without the need of any surface modification.