Amphiphilic polypeptide-polyoxazoline graft copolymer conjugate with tunable thermoresponsiveness: Synthesis and self-assembly into various micellar structures in aqueous and nonaqueous media
Amphiphilic polypeptide-polyoxazoline graft copolymer conjugate with tunable thermoresponsiveness: Synthesis and self-assembly into various micellar structures in aqueous and nonaqueous media
复制标题
DOI：
10.1016/j.polymer.2016.12.068
复制
发表时间：
2017-02-10
期刊：
影响因子：
4.6
通讯作者：
Mandal, Tarun K.
中科院分区：
文献类型：
--
作者：
Bose, Avijit;Jana, Somdeb;Mandal, Tarun K.
提出了一种基于两种不同的控制开环聚合(ROP)技术的“接枝”方法，合成了不同主链长度和侧链长度的聚酪氨酸-接枝-聚(2-乙基-2-恶唑啉)(PTYR-g-PEtOx)共聚物。该方法由酪氨酸N-羧酸酐和叠氮官能团聚2-乙基-2-恶唑啉(PEtOx-N-3)分别经酪氨酸N-羧酸酐和叠氮功能聚(2-乙基-2-恶唑啉)的ROP反应合成丙烯酰基功能化聚酪氨酸(PTYR-O-Pr)，然后通过CuAAC反应将它们接枝得到最终的接枝共聚物(GCC)。由于PTYR-g-PEtOx嵌段的存在，PTYR-g-PEtOx GCC在水中表现出LCST型可逆相变行为，这种可逆相变行为与其浓度、主链和悬挂嵌段的长度有关。同样，在水和非水介质中，两亲性的PTYR-g-PETOx GCC分子经历了自组装成球形单元胶束，以及随后的二次聚集体形成复合胶束。DLS研究表明，当溶液温度升高到LCST以上时，PTYR-g-PEtOx GCC的胶束复合胶束进一步聚集成更高阶的胶束聚集体，而胶束结构没有任何破坏。在水中，疏水染料尼罗红可以很容易地被包裹到PTyr-g-PEtOx胶束的疏水PTyr核中，即使在高于GCC的LCST时，该胶束也保持稳定，不会释放任何染料。(C)2017爱思唯尔有限公司。保留所有权利。
A "grafting onto" approach based on two different controlled ring-opening polymerization (ROP) techniques is developed to synthesize polytyrosine-graft-poly(2-ethyl-2-oxazoline) (PTyr-g-PEtOx) copolymer conjugates of varying main backbone and pendent chain lengths. This approach consists of syntheses of propargyl functionalized polytyrosine (PTyr-O-Pr) by ROP of tyrosine N-carboxyanhydride and azide functional poly(2-ethyl-2-oxazoline) (PEtOx-N-3) by cationic ROP separately followed by their grafting using CuAAC reaction to afford the final graft copolymer conjugate (GCC). Owing to the presence of pendent hydrophiphilic PEtOx block, PTyr-g-PEtOx GCC exhibits LCST-type reversible phase transition behavior in water, which is tunable with respect to its concentration and the lengths of the main backbone and the pendent block. Again, the amphiphilic PTyr-g-PEtOx GCC molecules undergo self assembly into spherical unit micelles and their consequent secondary aggregations into compound micelles both in aqueous and non-aqueous media. Upon increasing the solution temperature above LCST, micelles compound micelles of PTyr-g-PEtOx GCC undergo further aggregation into higher order micellar agglomerates without any disruption of micellar structures as observed from DLS study. A hydrophobic dye (nile red) can easily be encapsulated into the hydrophobic PTyr core of the PTyr-g-PEtOx micelles in water, which remains stable without any release of the dye even when the temperature is increased above the LCST of the GCC. (C) 2017 Elsevier Ltd. All rights reserved.