High resolution electrophysiological activity imaging of in-vitro neuronal networks

A prototype of a high density microelectrode array (MEA) for in-vitro recording of the electrophysiological activity of neuronal cell cultures has been developed. Based on standard CMOS technologies and dedicated post processing steps, it integrates 64×64 gold electrodes of 20×20 μm², organized in a pixel array on a surface of 2.56×2.56 mm². Each pixel has a dimension of 40×40 μm², resulting in an electrode separation of 40 μm. The on-chip integrated logic allows to randomly select each pixel individually, enabling the read out at high sampling rate of the whole active area or of limited zones of high neuronal activity. Additionally, each pixel integrates an amplifier circuit for local signal amplification with programmable gain and filtering. Simulation results and a first electrical characterisation in phosphate solution are presented in this paper