Advanced photodynamic agent from chondroitin sulfate/zinc phthalocyanine conjugate

In order to improve the therapeutic effect of zinc phthalocyanines (ZnPc), a photoactive nanodrug was prepared with acetylated chondroitin sulfate (AcCS), utilizing a simple chemical method. AcCS/ZnPc nanodrugs have a unimodal size distribution below 200 nm and a negative surface charge due to AcCS located on the nanodrug surface. In organic solvent such as DMSO or DMF, it has strong fluorescence intensity and generates abundant singlet oxygen. However, in aqueous solvent, AcCS/ZnPc nanodrugs developed a self-organized form which induced reducing fluorescence intensity and singlet oxygen generation. The cellular uptake of the nanodrug was determined using a cell lysis test and confocal microscopy observation. The results indicated that cellular internalization efficiency of the nanodrug was 1.7-2.1 times higher than that of free ZnPc. Also, the phototoxicity of the nanodrug was detected via MTT assay with or without light. Although free ZnPc did not exhibit cytotoxicity in both light and dark condition, the nanodrug exhibited increasing cytotoxicity after irradiation. We therefore suggest that AcCS/ZnPc nanodrugs may have promising applications as new photodynamic agents for the clinical treatment of various tumors.