Chlorin e6 conjugated silica nanoparticles for targeted and effective photodynamic therapy.

Photodynamic therapy (PDT) using photosensitizer drug has become an important therapeutic modality. However, the stability and targeted delivery of photosensitizer remain a critical challenge for efficient PDT treatment. In the present study, we developed chlorin e6 (Ce6)-conjugated and folic acid (FA)-decorated silica nanoparticles (silica-Ce6-FA) for targeted delivery of photosensitizer to the cancer cells. The synthesized NPs exhibited excellent stability and biocompatibility with MDA-MB-231 cells. The formulated particles were efficiently taken up by folate receptor-positive MDA-MB-231 cells, which were confirmed by comparative analysis with folate receptor-negative HepG2 cells. The folate receptor-targeted silica-Ce6-FA was highly accumulated inside the MDA-MB-231 cells than free Ce6. The obtained NPs produced singlet oxygen efficiently under 670-nm laser exposure. The cell-killing effect of silica-Ce6-FA was higher when compared with free Ce6 under PDT treatment. The PDT-induced mitochondrial damage and apoptotic cell death were detected in silica-Ce6-FA-treated cells.