Self-Assembled Porphyrin-Based Nanoparticles with Enhanced Near-Infrared Absorbance for Fluorescence Imaging and Cancer Photodynamic Therapy

Two novel meso-A₂B₂-porphyrins (P1 and P2) with symmetrical phenylethynyl groups were synthesized by introducing amphiphilic triethylene glycol moieties onto the parent structure, which improved the near-infrared (NIR) absorbance and resulted in efficient singlet oxygen (¹O₂) generation. Through solvent-exchange based self-assembly approach, the corresponding hydrophilic nanoparticles (NPs) were fabricated. Thereby, as-prepared NP1 and NP2 presented obvious red-shifted absorbance in NIR region with homogeneous size, superb biocompatibility, higher ¹O₂ generation, and good phototoxicity as well as low dark cytotoxicity. Furthermore, cellular uptake behavior of the NPs was evaluated by confocal microscopy, which demonstrated that the NPs could easily go through the cell membrane and distribute in cytoplasm with desired fluorescence imaging performance. All results suggest the potential application of the two porphyrin-based NPs in fluorescence imaging guided cancer photodynamic therapy.