Ionic conductive soluble starch hydrogels for biocompatible and anti-freezing wearable sensors

Hydrogel sensors have been widely researched for their good biocompatibility and mechanical properties similar to those of human skin, enabling the monitoring and transmission of a wide range of signals, thus promoting the development of flexible wearable electronic devices. However, long-term direct contact between hydrogel sensors and human skin can cause bacterial infection phenomena, and endowing hydrogel materials with antimicrobial properties is an important challenge in sensing applications. Here, an antimicrobial hydrogel was researched and explored via a freeze–thaw method introducing soluble starch, polyhexamethylene biguanide hydrochloride, glycerin, lithium chloride, and polyvinyl alcohol. The hydrogel expressed remarkable frost resistance, water retention, fatigue resistance, stability, sensitivity, responsiveness, electrical conductivity. The hydrogel exhibited an inhibitory loop resistant to Escherichia coli and Bacillus subtilis and emerged an inhibitory stability over 7 days. Simultaneously, the hydrogel expressed biocompatibility without tissue contamination, inflammation and other adverse phenomena under the skin of mice for 14 days. Furthermore, the hydrogel could record the signals of deformation during the process of the human motion. Therefore, the simple strategy is promising for medical fields including human motion detection, physiological signal recording and medical health detection.