Photophysical behavior and photodynamic therapy activity of conjugates of zinc monocarboxyphenoxy phthalocyanine with human serum albumin and chitosan.

Zinc monocarboxyphenoxy phthalocyanine (ZnMCPPc) was linked to human serum albumin (HSA) and chitosan via amide bond formation. The photophysical behavior and photodynamic therapy (PDT) activity (against human breast adenocarcinoma cell line (MCF-7 cells) of ZnMCPPc alone and its conjugates were investigated. The conjugates showed improved fluorescence, triplet and singlet oxygen quantum yields when compared to ZnMCPPc alone. The in vitro dark cytotoxicity and PDT studies were carried out at a dose of 3.6μg/mL to 57.1μg/mL. The in vitro dark cytotoxicity studies of ZnMCPPc showed cell viability <50% at 28.6μg/mL and 57.1μg/mL, while the conjugates showed > 50% in all their tested concentrations (3.6 to 57.1) μg/mL. Thus, conjugation of ZnMCPPc to HSA and chitosan improves its dark cytotoxicity, an important criteria for molecules meant for photodynamic therapy. Complex 1 showed the most efficacious PDT activity with cell viability <50% at concentration range of (14.3 to 57.1) μg/mL in comparison to the conjugates which only showed <50% cell viability at 28.6μg/mL and 57.1μg/mL for 1-HSA and 57.1μg/mL for 1-Chitosan.