Methanol Clipping Modification on Liquid Metal Surface Enhances Photothermal Performance and Biocompatibility

Photothermal conversion (PTC) enables materials to convert light energy, particularly in the near-infrared region, into heat. Photothermal materials have been widely applied in energy harvesting, sensing, and cancer therapy, while photothermal therapy (PTT) has emerged as a noninvasive tumor treatment with high targeting capability and low toxicity. Liquid metals (LMs) are promising photothermal agents due to their low toxicity, degradability, and tunable photothermal properties. However, their high reflectivity and poor stability significantly hinder practical applications. Herein, the three-phase system consisting of LMs, polytetrafluoroethylene (PTFE), and methanol (CH₃OH) is developed. Through contact electrification (CE) at the multiphase interface, mechanical energy is converted into chemical energy, thereby clipping CH₃OH molecules to synthesize LMs nanoparticles (LMNPs). LMNPs exhibit excellent photothermal performance and stability. Within 10 min, the photothermal conversion efficiency (PCE) is calculated to be 67.89% in the centrifugal liquid and 36.25% in deionized water, corresponding to heating rates of 4.74 and 5.96°C/min, respectively. Assays in vitro demonstrate that, at a concentration of 2000 µg/mL, the material reduces tumor cell viability to 54.57% while exhibiting no detectable cytotoxicity, indicating good biosafety. This work provides a novel surface engineering strategy for expanding the application of LMs in PTT.