High-density microelectrode arrays for electrophysiololgical activity imaging of neuronal networks

This work presents a new approach to high-density microelectrode arrays for spatially and temporally resolved images of in-vitro neuronal networks electrophysiological activity. Based on active pixel sensor technology (APS), the first chip design consists in an array of 64 x 64 (4096) pixels on an active area of 2.56 x 2.56 mm(2). Each pixel has a dimension of 40 x 40 mum(2) integrating a gold microelectrode of 20 x 20 mum(2). An in-pixel differential amplifier locally amplifies the extracellular potential, minimising the electrode-measuring circuit distance. The integrated circuit has a programmable gain and filtering for noise-speed trade-off. The network activity image is obtained by addressing the desired pixels at high sampling frequency and sequentially reading the chip output.