Array of gold ultramicroelectrodes for the simultaneous electrochemical detection of nitric oxide and peroxynitrite

Abstract

We report here on the design of assembled arrays of ultramicroelectrodes (UMEs) for the simultaneous and dynamic sensing of nitric oxide (NO) and peroxynitrite (ONOO–) released by cultured cells.The arrayed microelectrodes were designed in such a way to solve the sensitivity problem posed by the low concentrations of the target analytes: over 200 UMEs were short-circuited using photolithographic techniques and divided into two sections. Our results show that the short-circuited electrodes behave as typical UMEs over our experimental timescale whilst showing enhanced sensitivity. One section of arrayed UMEs was oriented toward the chemical modification of the electrodes surfaces to obtain selective NO-sensor with the desired selectivity against interfering analytes. To do so, we developed new combination of electropolymerisable membranes for the selective detection of NO, adapted to the arrayed configuration. The second section of arrayed UMEs was devoted to the selective detection of ONOO–. These disposable microelectrode platforms are then integrated within cell culture wells and plates, resulting in an easy-to-handle tool for cellular biology.