Edible temperature-responsive-adhesive thermogalvanic hydrogel for self-powered multi-sited fatigue monitoring

Abstract

Most traffic accidents are caused by driver fatigue, so achieving effective monitoring of fatigue status is particularly important. However, current detection methods mainly rely on complex biosensors that lack independence from power supply and adaptive adhesion, and have a risk of ingestion, especially for infants. Here, we propose an edible thermogalvanic hydrogel with I⁻/I₃⁻ as a redox pair for self-powered physiological monitoring by coupling thermogalvanic and piezoresistive effects. The gelatin/glycerol (Gel/GL) hydrogel exhibits excellent thermo-reversible gelling and temperature-responsive adhesion that can ensure on-demand reliable adhesion to skin for capturing physiological signals under hot compress and facilitate easy removal under cold compress due to the decomplexation and re-entanglement of gelatin chains. Moreover, a low-cost passive patch based on this self-adaptable thermogalvanic gel has been invented to simultaneously monitor breathing, blinking, yawning, and pulse at the canthus, philtrum and radial artery of the human body by acquiring thermoelectric signals correlated with physiological action, achieving a self-powered accurate surveillance of fatigue status, which can provide timely reminders based on fatigue levels. This work is beneficial for improving driving safety and exhibits the potential of the designed hydrogel for application in intelligent transportation.