| A novel asymmetrical aminoporphyrin (H2N-TPP-Cl) was synthesized and characterized as the initiator for atom transfer radical polymerization. Using CuCl/tris(2-dimethylaminoethyl)amine (Me6TREN) as the catalyst system, the ATRP of N-isopropylacrylamide (NIPAM) was carried out to afford a series of polymers (H2N-TPP-PNIPAM) with end group of aminoporphyrin. The structures of the initiator and polymers were characterized by means of FT-IR and1H NMR. The properties of the polymer, was anticipated to be used as photosensitizer in PDT, were investigated via methyl thiazolyl tetrazolium (MTT) assay.Polydispersity index (PDI) obtained by gel permeation chromatography (GPC) indicated that the molecular weight distribution was narrow (1.09<PDI<1.27). UV-Vis spectroscopic analysis confirmed that there is a strong absorption peak at420nm and there are several peaks at the lowest energy Q-band (approximately600nm). The lower critical solution temperatures (LCST=36.6-31.8℃) measured by turbidimetric assay of H2N-TPP-PNIPAM decreased with the increasement of the molecular weight (Mn,GPC=1830-16500) due to the incorporation of porphyrin group at the chain end. Fluorescence spectra manifested the luminescent properties of the materials. Cell cytotoxicity results indicated that the polymer exhibited low toxicity against normal cells (L929) and cancer cells (Hela). Phototoxicity (400-700nm irradiation) results showed that the polymer exhibited enhanced photodynamic activity and negligible cytotoxicity towards HeLa cells, but no significant cell death towards L929cells. The result of confocal laser scanning microscopy (CLSM) showed that the polymer can enter to the cytoplasm through endocytosis. What’s more, only a little polymer was accumulated in the normal cytoplasm and most of the polymer was accumulated in the cancer cytoplasm. H2N-TPP-PNIPAM possesses photodynamic effect and demonstrating high potentiality of binding acidic cancer cell particularly due to the alkalescence of aminoporphyrin. |
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