Thermoelectric hydrogels for self-powered wearable biosensing

Although the flourishing of the Internet of Things and artificial intelligence has accelerated the development of wearable smart bioelectronics, heavy reliance on external power remains a problem that needs to be solved. Thermoelectric materials have emerged as a promising solution, efficiently converting body heat into electrical energy to provide a stable and unrestricted power supply for wearables. Moreover, in the field of wearable thermoelectric biosensing, where flexibility is highly demanded, hydrogels with excellent electrical conductivity, flexibility and biocompatibility through structural and compositional optimization have become ideal materials for constructing biosensors and meet the diverse application needs of wearable bioelectronics. This article systematically reviews the latest research progress on thermoelectric gels for self-powered wearable biosensing, including the principles of thermoelectric operation, as well as the preparation, design, and application of thermoelectric hydrogels. The current state of thermoelectric gel-based wearable applications in the fields of temperature sensing, strain sensing, temperature-strain synergistic sensing, respiratory monitoring, and sweat analysis are displayed in the article. Finally, the paper summarizes the current challenges and prospects of thermoelectric gels in self-powered wearable bioelectronics, encouraging the rapid application and realization of thermoelectric gel-based smart wearables.