Synthesis of poly(ethylene glycol)-block-poly(ethylenimine) possessing an acetal group at the PEG end
Synthesis of poly(ethylene glycol)-block-poly(ethylenimine) possessing an acetal group at the PEG end
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DOI：
10.1021/ma000167c
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发表时间：
2000-08-08
期刊：
影响因子：
5.5
通讯作者：
Kataoka, K
中科院分区：
文献类型：
--
作者：
Akiyama, Y;Harada, A;Kataoka, K
利用PEG大分子引发剂技术合成了聚乙二醇（PEG）和聚乙烯亚胺（PEI）的新型线性嵌段共聚物。以3，3-二乙氧基丙醇钾（PDP）为引发剂，通过环氧乙烷（EO）的阴离子开环聚合反应，再用甲磺酰氯封端，合成了一端为缩醛基、另一端为甲磺酸基的杂遥爪聚乙二醇（acetal-PEG-SO2 CH 3）。然后以缩醛-PEG-SO2 CH 3为大分子引发剂，引发2-甲基-2-恶唑啉（Oz）的阳离子开环聚合，合成了嵌段共聚物缩醛-PEG-POz。嵌段效率达到几乎100%，允许通过初始单体/引发剂比率控制POz链段的分子量。POz链段中的重复乙酰基的碱性水解得到完全脱酰化的嵌段共聚物，其在PEG链端保留缩醛基团。由此获得的缩醛-PEG-聚（乙烯亚胺）嵌段共聚物可能作为靶向DNA载体在基因递送领域中具有潜在的实用性。
A new linear block copolymer of poly(ethylene glycol) (PEG) and poly(ethylenimine) (PEI) possessing an acetal group at the PEG chain end was prepared by a heterotelechelic PEG macroinitiator technique. Heterotelechelic PEG with an acetal group at one end and a methanesulfonic group at the other end (acetal-PEG-SO2CH3) was synthesized by the anionic ring-opening polymerization of ethylene oxide (EO) initiated with potassium 3,3-diethoxypropanolate (PDP), followed by end-capping with methanesulfonyl chloride. Acetal-PEG-SO2CH3 was then used as a macroinitiator for the cationic ring-opening polymerization of 2-methyl-2-oxazoline (Oz) to form the block copolymer, acetal-PEG-POz. The block efficiency attained almost 100%, allowing to control the molecular weight of the POz segment by the initial monomer/initiator ratio. Alkaline hydrolysis of the repeating acetyl groups in the POz segment gave the completely deacylated block copolymer retaining the acetal group at the PEG chain end. The acetal-PEG-poly(ethylenimine) block copolymer thus obtained may have a potential utility as targetable DNA carrier in the field of gene delivery.