A Recyclable Biomimetic Flexible Sensor Based on Gallium-Based Liquid Metal for Real-Time ECG Signal Monitoring

Gallium-based liquid metal (Ga-LM) has high electrical conductivity, excellent deformability, recyclability, and biocompatibility, simultaneously satisfying the core requirements of stretchable ECG sensors: high signal-to-noise ratio (SNR), low interfacial impedance, and conformability. A recyclable biomimetic flexible sensor based on Ga-LM was prepared in this study. Nanofiber membranes were fabricated as flexible substrates via electrospinning. Concurrently, conductive inks were obtained by mechanical shearing and ultrasonication. The biomimetic spider-web-structured sensor was ultimately constructed by printing the conductive ink onto the flexible substrate. Experimental results showed that the flexible sensor exhibited a relative resistance change of less than 50% after 700 tensile cycles, demonstrating excellent tensile and electrical stability. The sensor exhibited high recyclability, with an average Ga-LM recovery rate of 95.88%, and demonstrated self-healing capability. In addition, the sensor had favorable biocompatibility, and its air and moisture permeability supported skin-contact wearable applications. In real-time ECG signal monitoring, the sensor achieved a high SNR of 34.88 dB, comparable to that of traditional sensors while offering advantages in flexibility, recyclability, durability, and wearability. This study offers new insights into ECG-monitoring smart clothing, where biomimetic design and material recycling facilitate the sustainable development of flexible sensors.