Photocontrollable release and enhancement of photodynamic therapy based on host–guest supramolecular amphiphiles

A light-controlled porphyrinic photosensitizer release system was developed based on host–guest TPP–Azo/PEG–β-CD supramolecular amphiphiles, which could significantly enhance the efficiency of photodynamic therapy. TPP–Azo was prepared via esterification between TPP and Azo derivatives, and further used to construct supramolecular amphiphiles with PEG–β-CD. TEM images showed that TPP–Azo/PEG–β-CD amphiphiles can self-assemble into spherical micelles, and then disaggregate under irradiation with 365 nm UV light. The phototoxicity and bio-distribution of TPP–Azo/PEG–β-CD micelles against the MCF-7 cell line were also evaluated by MTT assay, flow cytometry and confocal scanning laser microscopy, respectively. According to MTT assay, the IC50 of the spherical micelle was 31.2 μg mL−1, but it became 20.6 μg mL−1 upon pre-irradiation with 365 nm UV light. This shows for the first time that UV light can well stimulate the release of porphyrin photosensitizers and improve the photodynamic therapy efficiency based on the system of host–guest supramolecular amphiphiles.