Liquid Metal Microparticles Phase Change Medicated Mechanical Destruction for Enhanced Tumor Cryoablation and Dual-Mode Imaging

Mechanical forces are crucial for normal living organisms as well as formation of tumor microenvironments. However, to date, there are rather limited trials to regulate the mechanical factors toward tumor treatment or imaging. Here, a synergistic antitumor therapy of cryoablation and gallium microparticles (GMs) mediated bomb-explosion-like mechanical destruction is proposed for the first time. Moreover, the GMs are demonstrated to enhance the T2 magnetic resonance imaging (MRI) effect and mediate the dual-mode imaging of computerized tomography (CT) and MRI. The GMs are found to exert a mechanical force to surrounding chitosan ice crystals during freezing, which is attributed to the volume expansion during the phase transition process. Meanwhile, the phenomenon of piercing gallium materials via a sword-like shape into the solid ice crystals is observed with a penetration length of 150 µm within 1 ms, which further shows the remarkable mechanical destruction to frozen ice crystals. Furthermore, a series of in vitro and in vivo results prove the negligible biotoxicity and good biocompatible of GMs. The in vivo synergistic therapy exhibits effective destructive results with reduced recurrence rate and prolonged survival. The present methods are expected to not only open an efficient tumor destructive approach, but also hold potential for advanced theranostic systems.