A Silicon Recording Probe with Integrated Ag/Agcl Reference Electrode for In-Situ PH Sensing

This paper presents a silicon recording probe with integrated in-situ Ag/AgCl reference electrode (ISA/ARE) for simultaneous pH sensing and electrophysiology recordings for the application neuroscience. The preparation of in-situ silver layer and its chlorination are realized by a constant current electrochemical plating method. The repeatable Ag/AgCl layer with stable potential has been verified by X-ray diffraction and electrochemical measurements. Meanwhile, the pH sensitivity of the combination of Iridium oxide (IrO
x
) electrodes and ISA/ARE is 54.7mV/pH. The area of ISA/ARE is only 7000µm
²
, which is highly compatible with the preparation process of silicon probes, and is suitable for integration into the front of micro shanks as an in-situ detection reference. In short, the unique fabrication method to realize miniaturized and integrated in-situ reference electrode is of great significance to biosensors.