Micro-electrode arrays for multi-channel motor unit EMG recording

We report an array of micro-electrodes, which can record multi-channel motor unit (MU) electromyogram (EMG) signals with a high spatial resolution. As a basic structure of the electrode, we fabricated an array of 200-μm-square Si-pyramids with the height of 200 μm by Tetramethylammonium hydroxide (TMAH), in order for robust MU-EMG recordings without conductive gel. Platinum (Pt) was used as the electrode material and parylene-C was used as the insulator for the Pt-electrode. The fabricated μEMG electrode array, which was connected to a recording system, clearly detected MU-EMG action potentials from a human forearm. In addition, different MU-EMG signals between the μEMG electrodes were detected by crooking the fingers. These results indicate that the μEMG array device becomes a powerful tool for medical applications including myoelectric prosthetic technologies.