Heavy-Atom-Free Nanoparticles Based on Boron Dipyrromethene Derivatives for Combined Photothermal and Photodynamic Cancer Therapy

Boron dipyrromethenes (BODIPYs) have been extensively studied in phototherapy against cancer. However, heavy-atom-free BODIPYs have been relatively less explored, and some of them are only used for photothermal therapy. Here, four heavy-atom-free BODIPYs with phenyl, naphthyl, anthracyl, or pyrenyl were synthesized and named B-mPh, B-mNa, B-mAn, and B-mPy, respectively. Stable nanoparticles (NPs) of the BODIPYs were prepared via the assembly with pluronic F127, which were named B-mPh NPs, B-mNa NPs, B-mAn NPs, and B-mPy NPs. The spin–orbit charge transfer (SOCT) of the anthracene group enhances the intersystem crossing (ISC) effect and improves the ability of B-mAn to generate singlet oxygen. Compared with other NPs, B-mAn NPs showed enhanced cytotoxicity upon irradiation. This kind of heavy-atom-free nanomaterials based on BODIPY, which promotes ISC by SOCT and enhances the generation of reactive oxygen species, plays an active part in the realization of combined photothermal and photodynamic therapy.