Abstract: Two kinds of triblock copolymer diols of poly L-lactate (PLLA) and polyethylene glycol (PEG) were synthesized by ring-opening polymerization.The copolymers were end-capped with methacrylate to form macro-crosslinker poly (L-lactide)-b-polyethylene glycol-b-poly (L-lactide) dimethacrylates (PELAMA) for preparation of pH-responsive hydrogel poly (PLEAMA-Acrylic acid-N-isopropylacrylamide) (PELAMA-AN) through photo-polymerization using N-isopropylmethacylamide (NIPAM),acrylic acid (AA) as monomers.PELAMA was characterized with FT-IR and 1H-NMR.The swelling ratio of hydrogels in PBS at various pH values was studied.Simultaneously degradation property and the controlled drug release behavior of hydrogels were also investigated.The results showed that PELAMA-ANs were typical pH-responsive hydrogels.The swelling ratio (1000%～2000%) of hydrogels in pH=7.4 PBS was two times bigger than that in acidic environment (pH=1.2)(400%～500%).Meanwhile,the periodically swelling/diswelling property of the hydrogels was observed by switching the pH values.It was found that the release rate of the doxorubicin hydrochloride at acidic condition (20%～40%) was smaller than that in a neutral environment (50%～60%) with in 10h.Also,the hydrogel released drug killed HeLa cells,which indicated that the PELAMA-AN hydrogels had the potential to be used as anticancer drug carriers.
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