Preparation Of W-doped TiO₂ Nanoparticles And Its Applications In Photoacoustic/CT Dual-modal Imaging And Synergistic Thermoradiotherapy Of Tumors

Cancer is one of the greatest threats to human health.Although radiation therapy,one of the traditional cancer treatments,can achieve treatment for deep tumors,it inevitably has side effects on normal tissues.As a minimally invasive method,photothermal therapy ablate tumor tissue by near-infrared light irradiation,but the current research mainly focuses on the first near-infrared region,and there are problems such as limited penetration depth and low maximum permissible exposure.Tumors treated by second near-infrared region photothermal therapy combined with enhanced radiation therapy is a synergistic treatment method that complements each other.In order to realize this idea,we broaden the absorption region of the titanium dioxide nanomaterial to the second near-infrared region by tungsten doping,and the obtained tungsten-doped titanium dioxide?TOW?nanoparticles exhibit 44.8%photothermal conversion efficiency and excellent stability performance under 1064 nm laser irradiation.The introduction of tungsten can realize enhanced radiotherapy due to its high atomic number.Second near-infrared region photothermal therapy combined with enhanced radiotherapy can effectively inhibit tumor growth of mice at relative low doses.At the same time,because of its intense absorption in second near-infrared region and the presence of tungsten,the nanoparticles can also be applied to second near-infrared region photoacoustic imaging and CT imaging.In order to enhance its biocompatibility,DSPE-PEG₅₀₀₀ was surface modified,and its biocompatibility and low toxicity were confirmed by long-term toxicity experiments in mice.Through the above work,it was confirmed that the multifunctional TOW nanoparticles have great potential in the diagnosis and treatment of cancer.