Xanthan gum-toughened nanocomposite conductive hydrogel for wearable sensors and smart livestock monitoring

Highly stretchable strain sensors based on conductive polymer hydrogels are rapidly becoming promising candidates for various wearable skin and smart monitoring devices. However, due to the inherent limitations of low adhesion and large hysteresis, existing strain sensors are not able to realize their full potential in applications. In this study, we harnessed the self-polymerization capability of polydopamine (PDA) to encapsulate silica (SiO 2 ) and load Fe 3+ onto the surface of PDA, resulting in the formation of SiO 2 @PDA-Fe nanoparticles. We incorporated polyacrylamide (PAM), SiO 2 @PDA-Fe nanoparticles, MXene, and xanthan gum (XG) into the system, thereby creating a multifunctional conductive hydrogel (SiO 2 @PDA-Fe/MXene/XG/PAM) characterized by excellent self-adhesion, impressive mechanical properties (1680 % strain), lack of cytotoxicity, anti-swelling, photothermal capabilities, and antimicrobial effects. Furthermore, the hydrogel strain sensor constructed from SiO 2 @PDA-Fe/MXene/XG/PAM exhibits outstanding sensing properties, including high sensitivity (GF = 3.14), durability, and stability over 2500 cycles. This sensor was employed for human motion detection, effectively adapting to the complex movements of various joints while delivering stable and reliable physiological signal data. It also serves as a wearable medical patch to monitor vital signs such as Electrocardiogram (ECG) and Electromyography (EMG). Additionally, we designed a pressure sensor capable of detecting whether piglets are pressed by sows, offering a reliable concept to enhance piglet survival rates, which holds significant potential for practical applications.