An Ultra-Stable, Oxygen-Supply Nanoprobe Emitting in Near-Infrared-II Window to Guide and Enhance Radiotherapy by Promoting Anti-Tumor Immunity

Currently, radiotherapy (RT) is the main method for cancer treatment. However, the hypoxic environment of solid tumors is likely to cause resistance or failure of RT. Moreover, high-dose radiation may cause side effects to surrounding normal tissues. In this study, a new type of nanozyme is developed by doping Mn (II) ions into Ag2Se quantum dots (QDs) emitting in the second near-infrared window (NIR-II, 1000-1700 nm). Through the catalysis of Mn (II) ions, the nanozymes can trigger the rapid decomposition of H2O2 and produce O-2. Conjugated with tumor-targeting arginine-glycine-aspartate (RGD) tripeptides and polyethylene glycol (PEG) molecules, the nanozymes are then constructed into in vivo nanoprobes for NIR-II imaging-guided RT of tumors. Owing to the radiosensitive activity of the element Ag, the nanoprobes can promote radiation energy deposition. The specific tumor-targeting and NIR-II emitting abilities of the nanoprobes facilitate the precise tumor localization, which enables precise RT with low side effects. Moreover, their ultra-stability in the living body ensures that the nanoprobes continuously produce oxygen and relieve the hypoxia of tumors to enhance RT efficacy. Guided by real-time and high-clarity imaging, the nanoprobe-mediated RT promotes anti-tumor immunity, which significantly inhibits the growth of tumors or even cures them completely.

Automated summary

A new type of nanozyme has been developed for tumor-targeted radiotherapy, which is constructed as in vivo nanoprobes guided by NIR-II imaging. These nanoprobes exhibit high stability in vivo and continuous oxygen generation to relieve tumor hypoxia, enhancing the efficacy of radiotherapy.