Stretchable Microneedle Array Electrode for Movement-Resistant Electroencephalogram Monitoring

To achieve long-term stable electroencephalogram (EEG) acquisition, avoiding motion-induced unstable contact between electrodes and skin is important. This work introduces a stretchable microneedle array (SMNA) electrode for movement-resistant EEG recording. The SMNA consists of a rigid epoxy microneedle array and an intrinsically stretchable styrene-ethylene-butylene-styrene (SEBS) substrate. The hard microneedles can penetrate the stratum corneum to realize low contact impedance, while the stretchable substrate can closely fit the curved scalp and adapt to the movement of the skin, reducing electrode displacement and detachment caused by movement. SMNA electrodes are assembled with customized polyurethane stretchable circuit boards to obtain 32-channel SMNA electrode patches, which enable 8 hours of high-quality EEG signal recording. After the long-term EEG monitoring, there was no skin damage, and the imprint left by the microneedles could be restored within 20 minutes.