Polymeric Nanoshell-Stabilized Liquid Metal for Bactericidal Photonanomedicine

Liquid metals (LMs), typically gallium and its alloys, are emerging functional materials for nanotechnology, yet the applications of LM nanoparticles (LMNPs) in biomedical areas are still in their infancy. This predicament occurs primarily because LMNPs are generally synthesized with inadequately protected surfaces rendering rapid uncontrollable oxidation in physiological conditions. Herein, we show that depositing a polymeric supra-nanoparticle shell on LMNPs through sonochemical assembly can alleviate their oxidation kinetics and maintain their designed functionalities, even during hyperthermia processing. The LMNPs with polymer encapsulation promise to be excellent candidate materials for stable, biocompatible, and reusable photothermal converters under near-infrared (NIR) laser irradiation, showing doubled photothermal conversion efficiency compared with unprotected ones. Besides, they are employed, alone or synergistically with a hydrogel matrix, as potent photothermal bactericidal agents, both in vitro and in vivo. Specifically, the LMNPs-embedded agarose hydrogel allows the disinfection and concurrently accelerated healing of full-thickness skin wounds. The nanoshell-enabled heat resistance of LMNPs is expected to broaden the horizons of LM-based nano/biomedicine, potentially against superbugs and cancer.