Liquid metals: Preparation, surface engineering, and biomedical applications

Liquid metals (LMs) with high thermal/electrical conductivity, extraordinary fluidity, and excellent biocompatibility have garnered considerable attention in the last decade. Especially, gallium (Ga)-based and bismuth (Bi)-based low-melting-point (near-physiological temperature) LMs have attracted tremendous attention from various biomedical applications. For example, the large specific surface area of LM NPs, excellent optical absorption (especially in the NIR) and magnetic induction heating properties of LMs have rendered them as excellent candidates for drug delivery platforms and photothermal/magnetocaloric applications in cancer therapy. In addition, LMs also possess advantages in imaging (e.g., PA imaging, CT imaging, and MRI), enabling the integration of diagnosis and treatment. Secondly, the efficient release of Ga3+ from Ga-based LMs in the humoral microenvironment and their magnetically responsive shape transformation characteristics make them suitable as novel antibacterial agents. Thirdly, the tunable hardness/stiffness and high conductivity/thermal properties of LMs support their application in the manufacture of wearable electronics and implantable biomedical devices. Due to the wide application potential of LMs in the biomedical fields, the preparation and surface engineering of LMs with different sizes and morphologies play an important role, which determine their properties and characteristics. This review aims to comprehensively discuss and provide a timely summary of the strategies for on-demand preparation and surface functionalization of LMs, including properties such as composition, size, morphology, and surface engineering. In addition, the biomedical applications owing to the adjustable structure and properties of LMs are also comprehensively summarized, such as cancer therapy, antibacterial treatment, and biomedical devices. Finally, the challenges associated with LMs and future perspectives are also briefly discussed in the end. (C) 2022 Elsevier B.V. All rights reserved.

Automated summary

Liquid metals (LMs), especially gallium (Ga)-based and bismuth (Bi)-based low-melting-point (near-physiological temperature) LMs, have attracted considerable attention in biomedical applications. They have great potential in drug delivery, photothermal/magnetocaloric applications, imaging, antibacterial treatment, and manufacturing of wearable electronics and implantable biomedical devices. The preparation and surface engineering of LMs play a crucial role in determining their properties and characteristics.