We report the first demonstration using a stable π-radical as a versatile photosensitizer for hypoxia-overcoming photodynamic therapy. After self-assembling the radical molecules into radical nanoparticles (NPs), the NPs show good water dispersibility, good biocompatibility, broad near-infrared (NIR) absorption and emission at ∼800 nm. Significantly, the radical NPs remain stable in various biological mediums, after 100 days exposure to the ambient environment, and even after long-term laser irradiation, which is superior to many reported radical-based materials. More importantly, upon 635 nm laser irradiation, sufficient superoxide radical (O₂⁻˙) generation and in vitro cytotoxicity were observed addressing the most important hurdle for successful PDT in the oxygen-deficient tumor microenvironment. In addition, the radical NPs are also demonstrated to have effective in vivo PDT efficacy, and excellent biosafety.

中文翻译：

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稳定的 π 自由基纳米粒子作为多功能光敏剂用于有效克服缺氧的光动力疗法

我们报告了第一次使用稳定的 π 自由基作为一种多功能光敏剂来克服缺氧的光动力疗法。将自由基分子自组装成自由基纳米粒子（NPs）后，纳米粒子表现出良好的水分散性、良好的生物相容性、在~800 nm处具有广泛的近红外（NIR）吸收和发射。值得注意的是，自由基纳米粒子在各种生物介质中保持稳定，暴露于周围环境 100 天后，甚至在长期激光照射后，这优于许多报道的基于自由基的材料。更重要的是，在 635 nm 激光照射下，产生足够的超氧自由基 (O ₂ ⁻ ˙) 和体外观察到细胞毒性解决了在缺氧肿瘤微环境中成功进行 PDT 的最重要障碍。此外，自由基NPs也被证明具有有效的体内PDT功效和优异的生物安全性。