Bio-electrodes Based on Poly(methy1 methacrylate) (PMMA) for Neural Sensing

Flexible and Implantable electrodes are proposed in neural sensing and muscle stimulation, particularly for peripheral nerve injuries. Functional stimulation have been used for decades in restoring muscle functions after injuries, and assist the nerve recovery process, which is often slow. Conventional electrodes are fabricated from precious metals such as platinum and gold. They are functional, but these materials also suffer from various drawbacks including the high cost, poor mechanical mismatch at the interface between the electrode tip and the soft human tissue, thus, leading to a high inter-facial impedance. This high impedance affects the quality of the signal to noise ratio (SNR) resulting in a poor recording for the neural activity. On the long term, these electrode materials can possibly damage the soft tissues due to their stiff nature. Therefore, several research activities were triggered to develop less expensive, easy to fabricate, biocompatible and flexible electrode materials that would offer solutions to the preceding problems. This work describes the synthesis of flexible and low-cost bio-electrodes based on Poly(methyl methacrylate) (PMMA) supported on silicone. The objective is to investigate their potential as candidates for sensing and recording peripheral neural signals. The synthesized electrodes were evaluated for their electrochemical properties when various mass ratios were used during the preparation process. The initial experimental results showed an impedance of 0.99 k□ for the bio-electrode sample. The impedance of these electrodes at 1 kHz was equal to 1.6 MΩ. Upon evaluation and comparison with the literature, the results appear to be very promising specifically when compared with polypyrrole (PPy)-conductive polymer and Iridium -based electrodes