Stable π-radical nanoparticles as versatile photosensitizers for effective hypoxia-overcoming photodynamic therapy

We report the first demonstration using a stable pi-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 similar to 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 (O-2(-)) 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.

Automated summary

The study demonstrates the use of a stable pi-radical as a photosensitizer for hypoxia-overcoming photodynamic therapy, showing stable radical nanoparticles with good water dispersibility and biocompatibility. The nanoparticles exhibit broad near-infrared absorption and emission, remaining stable in various biological mediums even after long-term laser irradiation. This approach addresses the challenge of oxygen deficiency in tumors, showing promising results in both in vitro and in vivo studies.