Fabrication of a Low-cost Multi-electrode Neural Probe for Brain Signal Recording

A neural probe made from a thin semiconductor material using an affordable microfabrication method is fabricated and characterized based on conventional measurements. The 4 microelectrodes with a surface area of 30 x 100 mu m2, as well as the tracks and pads of the probe were constructed using a thin layer of gold (Au) material, with an insulating layer of SU-8 used to cover the corresponding tracks. To assess the performance of the fabricated probe, both Electrochemical Impedance Spectroscopy (EIS) and artificial stimulation methods were used to characterize its properties. The microelectrode dimensions were specifically chosen to provide low impedance characteristics, which are necessary for the acquisition of Local Field Potential (LFP) signals. The invivo LFP data were obtained from male zebra finch presented with auditory stimuli. By properly filtering the extracellular recordings and analyzing the data, the obtained results were validated by comparing them with the signals acquired with a commercial neural electrode.