Combined detection of nitrite and bioelectrical activity using microelectrode arrays and a phosphate buffered saline solution

This paper presents the manufacturing of a microelectrode array, on printed circuit boards (PCB) and on silicon substrate, composed of 60 to 64 gold microelectrodes (between 4 µm and 70 µm each in diameter). The sensor has a measurement total area of 0.5 cm in radius, one reference electrode (1 mm 2 in area) and 28.4 mm wide and 28.4 mm long. These microelectrodes were used for checking and logging of extracelullar local field potential of cell culture and nitrite measurement in a phosphate buffered saline solution (electrolytical aqueous medium). In addition, an apparatus to shield from electromagnetic interference for connecting the arrays was designed to allow the capture of electrochemical reactions or electronic signals by the microelectrodes, for example: nitrite or cardiac potential measurement, respectively. Finally, biocompatibility tests of the array structures were performed. The preliminary electrical and biocompatibility testing, along with the collected data, has shown promising results pointing to the development of an accurate sensor after the completion of this study. The sensor has potentially a broader range of applications with only a few adaptations and due its good accuracy it can be a very useful resource for many chemical and biological applications.