Optimization of photothermal performance of hydrophilic W18O49 nanowires for the ablation of cancer cells in vivo

Near-infrared (NIR) laser-induced photothermal ablation (PTA) therapy has great potential to revolutionize conventional therapeutic approaches for cancers, and a prerequisite is to obtain biocompatible and efficient photothermal agents. Herein, we have developed hydrophilic W18O49 nanowires with average lengths of about 800 nm (abbreviated as W18O49-800 NWs) as an efficient photothermal agent, which are prepared by the solvothermal synthesis—simultaneous PEGylation/exfoliation/breaking two-step route. These W18O49-800 NWs exhibit stronger NIR photoabsorption than short nanowires with average lengths of about 50 nm (abbreviated as W18O49-50 NWs) that are prepared via a solvothermal one-step route. Under irradiation of 980 nm with a safe intensity of 0.72 W cm−2, the aqueous dispersion of W18O49-800 NWs (1.0 mg mL−1) exhibits the temperature elevation by 35.2 °C in 5 min; which is a 37.5% increase compared to that (by 25.6 °C) from W18O49-50 NWs (1.0 mg mL−1). More importantly, under 980 nm laser irradiation (0.72 W cm−2) for 10 min, in vivo cancer cells can be efficiently ablated by the photothermal effects of W18O49-800 NWs. Therefore, these W18O49-800 NWs can be used as a more efficient and promising photothermal nanoagent for the ablation of cancer cells in vivo.