Soft and Moldable Mg-Doped Liquid Metal for Conformable Skin Tumor Photothermal Therapy

As a class of emerging multifunctional soft materials, gallium-based liquid metal (LM) amalgams, metal/nonmetal particles dispersed in an LM environment, suggest a combination of intriguing properties. In this article, Mg particles in gallium-indium alloy for making new conceptual biomedical materials, which can adapt to any irregular skin surface, are introduced, and superior photothermal effect with a 61.5% photothermal conversion (PTC) increase with respect to that of the LM is realized. The formation of a new intermetallic phase Mg₂Ga₅ and adjustable surface roughness, which guarantees a rapid temperature increase when illuminated by laser, are found to be responsible for the photothermal effect enhancement. The obtained soft metallic mixtures also possess excellent thermal conductivity, favorable formability, together with benign biocompatibility. The potential use of the currently produced LM mixtures for conformable photothermal therapy (PTT) of skin tumors, which is hard to precisely heat otherwise via conventional ways, is explored. The soft Mg-GaIn mixtures can adapt to irregular tumor shapes to achieve conformable and minimal invasive tumor treatment. In vivo experiments on skin-tumor-bearing mice show obvious tumor growth suppression and life span extension after PTT treatment. As a novel functional PTC material, the Mg-GaIn mixtures exhibit promising potentials in the coming clinical cancer theranostics.