Interfacial Polydentate Complexation with Phytic Acid Enables Oxidation-Resistant Liquid Metal Nanoparticles

Abstract

Liquid metal nanoparticles (LM NPs) hold great promise for applications in catalysis, soft robotics, electronics, microfluidics, and biomedicine. Their practical utilization, however, is often hindered by inevitable oxidation and dealloying of LM NPs during preparation, storage, and application. To overcome the challenges, we develop a green stabilization strategy using phytic acid (PA), a natural ligand with six strong electron-donating phosphate groups. Each PA molecule provides six anchor sites that strongly coordinate with gallium ions (Ga³⁺), forming a robust chemical passivation film on the nanoparticle surface. By tuning the concentration of PA solution, we can control the thickness of the passivation film and nanoparticle size of PA-complexed LM NPs (PA/LM NPs), resulting in prolonged aqueous stability for up to two months. Besides, PA/LM NPs exhibit enhanced photothermal stability compared with bare LM NPs. As a proof of concept, we demonstrate the application of PA/LM NPs in the photothermal therapy of bone tumors, where the PA-mediated polydentate complexing strategy improves both biocompatibility and bone affinity of nanoparticles. In vitro experiments confirm efficient photothermal ablation of osteosarcoma cells. This polydentate complexing strategy helps stabilize LM NPs, enabling their application in more demanding environments.