Novel albumin-binding photodynamic agent EB-Ppa for targeted fluorescent imaging guided tumour photodynamic therapy.

The targeted and novel albumin-binding strategy has been attractive in the field of cancer therapy. Herein, we have developed an organic small molecule-based photosensitizer, Evans Blue-Pyropheophorbide-alpha (EB-Ppa), to treat solid tumors with extremely high photodynamic therapeutic efficiency, which is stable in serum-containing aqueous media and can effectively accumulate in the tumor site due to the enhanced permeability and retention (EPR) effect. Particularly, after the photodynamic therapeutic treatment with EB-Ppa, all breast tumors (4T1 cell line) xenografted in nude mice shrink fast due to the singlet oxygen generated by EB-Ppa with laser irradiation. Furthermore, EB-Ppa shows negligible toxicity in major organs. These results demonstrate that EB-Ppa presents the great potential of photodynamic therapy for efficient tumor treatment.