All-fibrous multimodal sensor patch for synchronous monitoring of biomechanical and bioelectrical signals

Monitoring physiological signals is essential for individual healthcare. Muscles, which are the primary components responsible for human movement, produce biomechanical and bioelectrical signals during contraction and relaxation. However, the simultaneous monitoring of these two types of signals remains challenging. In this work, a four-layered all-fibrous multimodal sensor patch (FMSP) is developed, comprising a structured pressure sensor unit and an electrophysiological electrode unit. This patch utilizes a pressure sensor to monitor force myography (FMG) signal and an electrophysiological electrode to track electromyogram (EMG) signal, enabling simultaneous monitoring of both during muscle activity. The pressure sensor, featuring a micro-hump structure on the fibrous membrane surface, achieves a high sensitivity of 148.1 kPa⁻¹ and a broad monitoring range of 0.054 to 200 kPa. Additionally, an adhesive fibrous membrane enables the electrophysiological electrode to maintain a high adhesion strength of 67.6 kPa. This ensures a stable and low skin-electrode interface impedance and demonstrates a high signal-to-noise ratio (SNR) of 21.8 dB for the EMG signal, significantly improving upon commercial gel electrodes. The FMSP can synchronously monitor both FMG and EMG signals during arm movements, distinguishing between different bending angles and lifting weights. This multimodal sensor patch shows promising applications in muscle health monitoring, wearable intelligent sensing, and human-machine interfaces.