Sequential Protein-Responsive Nanophotosensitizer Complex for Enhancing Tumor-Specific Therapy.

A major challenge in cancer treatment is the development of effective tumor-specific therapeutic methods that have minimal side effects. Recently, a photodynamic therapy (PDT) technique using activatable photosensitizers (aPSs) has shown great potential for cancer-specific treatment. Here, we develop a sequential protein-responsive aPS (PcC4-MSN-O1) that is based on zinc(II) phthalocyanine derivative (PcC4)-entrapped mesoporous silica nanoparticles (MSNs) and a wrapping DNA (O1) as a biogate. Inside the nanostructure of PcC4-MSN-O1, PcC4 shows self-quenching photoactivity. However, when PcC4-MSN-O1 sequentially reacts with telomerase and albumin, its photoactivity is dramatically turned on. Therefore, PcC4-MSN-O1 displays selective phototoxicity against cancer cells ( e.g., HeLa) over normal cells ( e.g., HEK-293). Following systemic PcC4-MSN-O1 administration, there is an obvious accumulation in HeLa tumors of xenograft-bearing mice, and laser irradiation clearly induces the inhibition of tumor growth. Moreover, the time-modulated activation process in tumors and the relatively fast excretion of PcC4-MSN-O1 indicate its advantages in reducing potential side effects.