Development of planar microelectrode array for extracellular characterization of action potentials in sinoatrial node cells

In this research work we prototyped a planar microelectrode arrays that utilize SU-8 as the insulating material for non-invasive chronically characterization of action potentials from SA node cells. The microelectrode arrays are fabricated to form a microchannel based extracellular action potential characterization system which comprises a 2 by 50 linear microelectrode array for acquiring the action potentials with the principle of capacitive coupling and a full customized CMOS analog bio-signal readout ASIC for bio-signal conditioning and processing. The prototyped multi-channel mixed signal fully-customized CMOS biosensor analog front-end serves as the low magnitude action potential signal readout circuitry, which is comprised of analog signal buffers, high gain amplifier and control/interface. The concept of using epoxy-based photoresist SU-8 as the insulator instead of the conventional silicon nitride or silicon dioxide is due to the high insulation property and bio-compatibility of the SU-8 material. This biocompatible planar microelectrode arrays with microchannels provides the biological scientists powerful tools for the long term non-invasive study of action potentials from SA node cells to screen libraries of chemical compounds for new drug candidates.