Dong Chang-Ming, Sun Xue-Long, Faucher Keith M, Apkarian Robert P, Chaikof Elliot L
Laboratory for Biomolecular Materials Research, Department of Surgery, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
Biomacromolecules. 2004 Jan-Feb;5(1):224-31. doi: 10.1021/bm0343500.
Glycopolymer-polypeptide triblock copolymers of the structure, poly(l-alanine)-b-poly(2-acryloyloxyethyl-lactoside)-b-poly(l-alanine) (AGA), have been synthesized by sequential atom transfer radical polymerization (ATRP) and ring-opening polymerization (ROP). Controlled free radical polymerization of 2-O-acryloyl-oxyethoxyl-(2,3,4,6-tetra-O-acetyl-beta-d-galactopyranosyl)-(1-4)-2,3,6-tri-O-acetyl-beta-d-glucopyranoside (AEL) by ATRP with a dibromoxylene (DBX)/CuBr/bipy complex system was used to generate a central glycopolymer block. Telechelic glycopolymers with diamino end groups were obtained by end group transformation and subsequently used as macroinitiators for ROP of l-alanine N-carboxyanhydride monomers (Ala-NCA). Gel permeation chromatography (GPC) and nuclear magnetic resonance (NMR) spectroscopy analysis demonstrated that copolymer molecular weight and composition were controlled by both the molar ratios of the Ala-NCA monomer to macroinitiator and monomer conversion and exhibited a narrow distribution (Mw/Mn = 1.06-1.26). FT-IR spectroscopy of triblock copolymers revealed that the ratio of alpha-helix/beta-sheet increased with poly(l-alanine) block length. Of note, transmission electron microscopy (TEM) demonstrated that selected amphiphilic glycopolymer-polypeptide triblock copolymers self-assemble in aqueous solution to form nearly spherical aggregates of several hundreds nanometer in diameter. Significantly, the sequential application of ATRP and ROP techniques provides an effective method for producing triblock copolymers with a central glycopolymer block and flanking polypeptide blocks of defined architecture, controlled molecular weight, and low polydispersity.
通过顺序原子转移自由基聚合（ATRP）和开环聚合（ROP）合成了结构为聚（L-丙氨酸）-b-聚（2-丙烯酰氧基乙基-乳糖苷）-b-聚（L-丙氨酸）（AGA）的糖聚合物-多肽三嵌段共聚物。使用二溴二甲苯（DBX）/CuBr/联吡啶络合物体系通过ATRP对2-O-丙烯酰氧基乙氧基-（2,3,4,6-四-O-乙酰基-β-D-吡喃半乳糖基）-（1-4）-2,3,6-三-O-乙酰基-β-D-吡喃葡萄糖苷（AEL）进行可控自由基聚合，以生成中心糖聚合物嵌段。通过端基转化获得具有二氨基端基的遥爪糖聚合物，随后将其用作L-丙氨酸N-羧酸酐单体（Ala-NCA）的ROP的大分子引发剂。凝胶渗透色谱（GPC）和核磁共振（NMR）光谱分析表明，共聚物的分子量和组成受Ala-NCA单体与大分子引发剂的摩尔比以及单体转化率的控制，并且具有窄分布（Mw/Mn = 1.06-1.26）。三嵌段共聚物的FT-IR光谱显示，α-螺旋/β-折叠的比例随聚（L-丙氨酸）嵌段长度的增加而增加。值得注意的是，透射电子显微镜（TEM）表明，所选的两亲性糖聚合物-多肽三嵌段共聚物在水溶液中自组装形成直径为数百纳米的近球形聚集体。重要的是，ATRP和ROP技术的顺序应用为生产具有中心糖聚合物嵌段和侧翼多肽嵌段的三嵌段共聚物提供了一种有效的方法，该三嵌段共聚物具有确定的结构、可控的分子量和低多分散性。
