Hydrophobic IR780 encapsulated in biodegradable human serum albumin nanoparticles for photothermal and photodynamic therapy.

It has been reported that IR780 iodide, a near-infrared dye, can be applied for cancer imaging, photodynamic therapy (PDT) and photothermal therapy (PTT). However, the hydrophobicity and toxicity of IR780 severely limit its further clinical applications. In this study, human serum albumin was used to load IR780 to form nanoparticles (HSA-IR780 NPs) by protein self-assembly. Compared to free IR-780, the solubility of HSA-IR780 NPs was greatly increased (1000-fold) while the toxicity was decreased (from 2.5 mg kg(-1) to 25 mg kg(-1)). Moreover, both PTT and PDT could be observed in HSA-IR780 NPs, as determined by increased temperature and enhanced generation of singlet oxygen after laser irradiation at a wavelength of 808 nm. In vivo studies also showed a great tumor inhibition by the injection of HSA-IR780 NPs into tumor-bearing mice. Therefore, HSA-IR780 NPs may serve as a promising substitute for IR780 in further clinical PDT and PTT.