Flexible yet Durable\nMicroneedle Electrodes Based\non Nanowire-Embedded Polyimide for Precise Wearable Electrophysiological\nMonitoring

A precise recording of electrophysiological signals requires\nhigh-performance\nflexible bioelectrodes to build a robust skin interface. The past\ndecade has witnessed encouraging progress in the development of elastomeric\nelectrodes for wearable electrophysiological monitoring; however,\nit remains challenging to achieve excellent flexibility, conformal\ncontact, and high durability simultaneously. Herein, we report on\nan effective method to fabricate flexible yet durable microneedle\nelectrodes (MEs) based on vertically aligned gold nanowires (Au NWs)\nembedded polyimide (PI), which meet the above three design requirements.\nThe Au NWs embedded PI MEs could build conformal contact with human\nskin and maintain electrical stability with minimal contact impedance\nby effectively penetrating the stratum corneum of the skin. In comparison\nstudies, we found our MEs outperformed conventional gel or elastomeric\nsoft electrodes. We further integrated the vertical Au-NW MEs into\na wearable healthcare system and achieved wireless real-time recordings\nof electromyography (EMG) and electrocardiography (ECG) with high\nsignal-to-noise ratios (SNRs) and low motion artifacts. Our fabrication\nstrategy opens a new route to improve the durability and reliability\nof emerging nanomaterial-based soft bioelectrodes for long-term wearable\nhealthcare applications.