通过与L-丙氨酸进行无规共聚来调节热响应性OEG化聚-L-谷氨酸的相变温度。

Tuning the phase transition temperature of thermal-responsive OEGylated poly-L-glutamate via random copolymerization with L-alanine.

作者信息

Yu Lei, Fu Wenxin, Li Zhibo

机构信息

Beijing National Laboratory for Molecular Science (BNLMS), Institute of Chemistry, Chinese Academy of Science, Beijing, 100190, China.

出版信息

Soft Matter. 2015 Jan 21;11(3):545-50. doi: 10.1039/c4sm02270j.

DOI:10.1039/c4sm02270j

PMID:25420954

Abstract

Two series of copolymers were prepared by ring-opening polymerization (ROP) of γ-(2-methoxyethoxy)esteryl-L-glutamate (L-EG2Glu) N-carboxyanhydride (NCA) and L-alanine (L-Ala) using HMDS and PEG-NH2 as initiator, respectively. Poly-(L-EG2Glu-co-L-Ala) displayed lower critical solution temperature (LCST) behavior but had a lower phase transition temperature than poly-L-EG2Glu at similar molecular weight (MW). The clouding point (CP) of random copolypeptides can be tuned by altering the alanine content and overall MW. Circular dichroism (CD) and Fourier transform infrared spectroscopy (FTIR) indicated that the thermal-responsive properties depended on the content of ordered conformations. PEG-b-poly-(L-EG2Glu-co-L-Ala) can spontaneously form hydrogels in water at room temperature. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) revealed that these hydrogels were formed by nanoribbons. The intermolecular hydrogen bonding among copolypeptide blocks accounted for the nanoribbon assemblies and hydrogel network formation.

摘要

分别以六甲基二硅氮烷（HMDS）和聚乙二醇胺（PEG-NH₂）为引发剂，通过γ-(2-甲氧基乙氧基)酯基-L-谷氨酸（L-EG2Glu）N-羧基环内酸酐（NCA）与L-丙氨酸（L-Ala）的开环聚合（ROP）制备了两个系列的共聚物。聚（L-EG2Glu-co-L-Ala）表现出较低临界溶液温度（LCST）行为，但在相似分子量（MW）下，其相转变温度低于聚-L-EG2Glu。无规共多肽的浊点（CP）可通过改变丙氨酸含量和总分子量来调节。圆二色性（CD）和傅里叶变换红外光谱（FTIR）表明，热响应特性取决于有序构象的含量。聚乙二醇-b-聚（L-EG2Glu-co-L-Ala）在室温下能在水中自发形成水凝胶。透射电子显微镜（TEM）和原子力显微镜（AFM）显示，这些水凝胶是由纳米带形成的。共多肽嵌段之间的分子间氢键导致了纳米带组装和水凝胶网络的形成。