Advances of liquid metal hydrogel composites in biomedical applications

Liquid metals (LMs) and hydrogels each represent advanced frontiers in emerging biomaterials and biomedicine. In particular, LMs, which possess liquid and metallic properties at normal temperature and pressure, are a new type of conductive material that has gained increasing attention. When integrated into hydrogel polymers, LMs act exceptionally as an "active" filler and/or responsive element. The presence of LMs in these composites endows the liquid metal hydrogel composites (LMHGs) with intriguing properties such as self-healing, flexibility, responsiveness, and thermal and electrical conductivity. These properties significantly broaden their applications in various fields. This review introduces the featured performances of LMs, as well as emphatically summarizes advanced biomedical applications of LMHGs involving medical electronics, biomedical engineering, and soft electronics actuators. The present opportunities and challenges associated with the biological applications of LMHGs are also discussed. .