Galactosyl BODIPY-based nanoparticles as a type-I photosensitizer for HepG2 cell targeted photodynamic therapy

We report a galactosyl diiodo-BODIPY-based nanoparticles as type-I photosensitizer (PS) with high water solubility for HepG2 cell targeted photodynamic therapy. Functionalized galactoside and glucoside were introduced into diiodo-BODIPY to obtain BP1 and BP2, respectively. The glycolyl PSs could self-assemble to form the nanoparticles BP1-NP and BP2-NP with red-shifted near-infrared (NIR) absorption and fluorescence at 682 nm and 780 nm, as well as excellent chemo- and photo-stability. In comparison to the monomer in DMSO, the aggregated photosensitizers in the nanoparticles enabled the sensitization of oxygen to superoxide (O₂˙^-) through a type-I process, while repressing the generation of singlet oxygen (¹O₂) through a type-II process. The galactosyl-modified BP1-NPs could target and concentrate on HepG2 cells, subsequently generating O₂˙^- and ¹O₂ to trigger cell death under 660 nm light irradiation. This work provides an efficient strategy for the construction of glycoside-recognized type-I photosensitizers for tumor cell imaging and photodynamic therapy.