Preparation of compound high water-soluble chlorin-based photosensitizer and its photodynamic cell therapy performance test

Objective To explore an easy and convenient strategy to improve the solubility of chlorin e6(Ce6) in aqueous medium and evaluate its photodynamic activity at the cellular level.Methods The highly water-soluble photosensitizer CHCe6 was prepared by supramolecular combination of bionutrient choline(Choline) and photosensitizer Ce6. The photophysical properties of the photosensitizer CHCe6(including UV-Vis absorption spectrum, and singlet oxygen quantum yield) were characterized by spectrometry. The stability of photosensitizers CHCe6 and Ce6 in aqueous medium was analyzed by UV-Vis absorption spectroscopy. The cellular uptakes of photosensitizers CHCe6 and Ce6 by murine triple-negative breast cancer 4T1 tumor cells were analyzed. DHE and AO stainings were conducted to assess the production of reactive oxygen species of photosensitizers CHCe6 and Ce6 and their effects on lysosomal membrane structure. The phototoxicity and dark toxicity of photosensitizers CHCe6 and Ce6 to 4T1 tumor cells were evaluated by cytotoxicity experiments.Results The highly water-soluble photosensitizer CHCe6 was successfully prepared by the supramolecular combination strategy. CHCe6 exhibited high singlet oxygen quantum yield and photostability under low-power LED irradiation. Cellular uptake experiments showed that CHCe6 was effectively internalized by 4T1 tumor cells by a time-dependent manner. DHE and AO stainings further confirmed that CHCe6 efficiently produced reactive oxygen species in 4T1 tumor cells under low-power LED irradiation and rapidly transported to the cytoplasm through the lysosomal membrane disruption. Furthermore, cytotoxicity experiments showed that CHCe6 exhibited lower dark toxicity and higher phototoxicity.Conclusions Compared with Ce6, CHCe6 exhibits higher water solubility, with better photostability and remarkable capacity to produce reactive oxygen species. Upon low-power LED irradiation, CHCe6 can significantly inhibit the growth of murine triple-negative breast cancer 4T1 cells, demonstrating good clinical application potential.