Low-Cost, Low-Impedance Polyimide Based Micro-Needle Array (PI-MNA): A Minimally Invasive Flexible Dry Electrode for Surface Bio-Potential Monitoring

In this work, we propose a minimally invasive dry flexible electrode device containing a micro-needle array entirely based on polyimide (PI-MNA) for surface bio-potential sensing and monitoring. Owing to the spiky tips, extensibility and biocompatibility, the gold-coated PI needles are able to penetrate high resistivity stratum corneum to realize low-impedance and nontoxic skin-electrode contact without tedious skin-preparation and severe invasiveness. The PI-MNA was mainly fabricated via twice of conformal moulding technique without any costly or complicated process. A specific data processing system was developed for PI-MNAs, and satisfactory bio-potentials was recorded.