High performance zwitterionic hydrogels for ECG/EMG signals monitoring

Zwitterionic hydrogel is receiving growing interest due to their unique structure and properties. Nevertheless, overcoming the problem of weak mechanical strength and integrating multiple functions into one zwitterionic hydrogel is still a great challenge. Herein, we have designed an ion-conductive (3.0 S/m) zwitterionic hydrogel featured with many desirable properties of high strength (134 kPa), transparency (the average light transmission closes to 90%), flexibility (up to 287%), self-adhesion (187.5 N/m), low contact impedance (79 Ω) and fatigue resistance. The zwitterionic hydrogel exhibits good flexibility and fatigue resistance due to the combination of chemical cross-linking and hydrogen bonding in the structure. Additionally, it can adhere extensively to various substrate surfaces through intermolecular forces and detect small physical movements, simultaneously capturing the ECG and EMG signals of the body with precision and stability. It also demonstrates higher sensitivity (0.46) and lower RMS noise (6.83 μV) in static measurements than those of current commercial electrodes. We believe that the designed zwitterionic hydrogel has promising applications in the field of wearable biosensors.