Engineering Liquid Metal Nanoparticles for Wearable Devices

Liquid metals (LMs) are emerging as highly promising materials for wearable devices owing to their exceptional properties, such as high electrical and thermal conductivity, biocompatibility, flexibility, and unique surface characteristics. Through surface engineering with ligands, polymers, and nanomaterials, LMs can be processed into stable bioinks with enhanced oxidation resistance, adhesion, and multifunctionality. These bioinks are further integrated into microneedle and patch-based wearables via fabrication strategies, including photolithography, micromolding, 3D printing, screen and inkjet printing, and direct writing. Such integration enables diverse biomedical applications, ranging from physiological signal monitoring and sweat or temperature sensing to wound healing, antibacterial therapy, and controlled drug delivery. Despite these advances, challenges remain in application maturity, long-term stability, biocompatibility, and scalable manufacturing. Accordingly, this review summarizes these challenges and outlines future directions for LM-based wearable biomedical devices.