Recyclable hydrogel for human-machine interface of multi-mode human vital signal acquisition

Ionic conductive hydrogels have emerged as one of the most promising alternatives to wearable sensors for human motion detecting, owing to their unique advantages in biocompatibility, conductivity and flexibility. However, the current hydrogel electronics still face the limitations of non-reusability and single-signal detection capability. Here, an ionic conductive hydrogel based on polyvinyl alcohol, sodium alginate fibers, and collagen was prepared by simulating the network structure and ion conduction mechanism of organisms for dual-mode signal acquisition of human motion and electrophysiological signals. Through the synergistic regulation of sodium alginate fibers and collagen, the hydrogels exhibit skin-like mechanical properties with low modulus, high toughness, and fatigue resistance to maximize the wearing comfort and motion detection capabilities of hydrogel wearable sensors. Furthermore, the hydrogel conductors with ion-transporting behavior close to organisms can be used as epidermal electrodes to collect the epidermis biopotential containing important human physiological information. As a result, through the rational design and assembly of wearable devices, hydrogels can be used to not only continuously and accurately identify whole-body motion signals, but also collect different electrophysiological signals such as electromyogram and electrocardiogram signals. Notably, the hydrogel based on the non-covalent cross-linked structure is completely recyclable, which can be arbitrarily reconstituted into new electronic devices while retaining the original function, improving the reusability of the hydrogels and reducing electronic waste.