Self-assembly of polypeptide-containing ABC-type triblock copolymers in aqueous solution and its pH dependence.
Self-assembly of polypeptide-containing ABC-type triblock copolymers in aqueous solution and its pH dependence.
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DOI：
10.1021/bm0609792
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发表时间：
2007-02
影响因子：
6.2
通讯作者：
Jingru Sun;C. Deng;Xuesi Chen;Haijun Yu;Huayu Tian;Jingru Sun;X. Jing
中科院分区：
文献类型：
--
作者：
Jingru Sun;C. Deng;Xuesi Chen;Haijun Yu;Huayu Tian;Jingru Sun;X. Jing
研究了新型可生物降解ABC型三嵌段共聚物聚乙二醇-聚L-乳酸-聚L-谷氨酸（PEG-PLLA-PLGA）的自组装。在水介质中，它自组装成一个球形胶束，其中疏水PLLA片段在核中，两个亲水片段PEG和PLGA在壳中。在PEG和PLLA嵌段长度固定的情况下，胶束的直径取决于PLGA嵌段的长度和介质中H2O/DMF的体积比。当PLGA嵌段足够长时，自组装的形态是pH依赖性的。它在pH 4.5的水介质中组装成球形胶束，并在pH 3.2或以下组装成连接棒。共聚物的临界胶束浓度（cmc）随溶液pH值的降低而变化，在适当的pH值下，两种聚集态可以相互转化。这种可逆性归因于LGA残基中COOH基团的解离和中和。当PLGA嵌段比PEG或PLLA嵌段短时，它仅在各种pH值下组装成球形胶束。
Self-assembling of novel biodegradable ABC-type triblock copolymer poly(ethylene glycol)-poly(L-lactide)-poly(L-glutamic acid) (PEG-PLLA-PLGA) is studied. In aqueous media, it self-assembles into a spherical micelle with the hydrophobic PLLA segment in the core and the two hydrophilic segments PEG and PLGA in the shell. With the lengths of PEG and PLLA blocks fixed, the diameter of the micelles depends on the length of the PLGA block and on the volume ratio of H(2)O/dimethylformamide (DMF) in the media. When the PLGA block is long enough, morphology of the self-assembly is pH-dependent. It assembles into the spherical micelle in aqueous media at pH 4.5 and into the connected rod at or below pH 3.2. The critical micelle concentration (cmc) of the copolymer changes accordingly with decreasing solution pH. Both aggregation states can convert to each other at the proper pH value. This reversibility is ascribed to the dissociation and neutralization of the COOH groups in the LGA residues. When the PLGA block is short compared to the PEG or PLLA block, it assembles only into the spherical micelle at various pH values.