A Near Infrared Light Triggered Hydrogenated Black TiO2 for Cancer Photothermal Therapy

White TiO 2 nanoparticles (NPs) have been widely used for cancer photodynamic therapy based on their ultraviolet light–triggered properties. To date, biomedical applications using white TiO 2 NPs have been limited, since ultraviolet light is a well‐known mutagen and shallow penetration. This work is the first report about hydrogenated black TiO 2 (H‐TiO 2 ) NPs with near infrared absorption explored as photothermal agent for cancer photothermal therapy to circumvent the obstacle of ultraviolet light excitation. Here, it is shown that photothermal effect of H‐TiO 2 NPs can be attributed to their dramatically enhanced nonradiative recombination. After polyethylene glycol (PEG) coating, H‐TiO 2 ‐PEG NPs exhibit high photothermal conversion efficiency of 40.8%, and stable size distribution in serum solution. The toxicity and cancer therapy effect of H‐TiO 2 ‐PEG NPs are relative systemically evaluated in vitro and in vivo. The findings herein demonstrate that infrared‐irradiated H‐TiO 2 ‐PEG NPs exhibit low toxicity, high efficiency as a photothermal agent for cancer therapy, and are promising for further biomedical applications.