Monodisperse, Thermoresponsive Microgels Based on Poly(ethylene Glycol) Derivative Polymers

基于聚乙二醇衍生物聚合物的单分散热响应微凝胶

• 批准号: 0805089
• 负责人: Zhibing Hu
• 金额: $ 30.9万
• 依托单位: University of North Texas
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-06-01 至 2011-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0805089&HistoricalAwards=false
• 关键词: Monodisperse; Thermoresponsive; Microgels; Based; Poly

TECHNICAL SUMMARY:Synthesizing monodisperse polymer colloids is usually the first step toward the study of self-assembling processes and especially important for the fabrication of nanostructured materials. The current available polymer colloids include polystyrene, polymethyl methacrylate (PMMA) and poly-N-isopropylacrylamide (PNIPAM) spheres and their derivatives. The objective of this proposed project is to create new monodisperse, thermo-responsive polymer colloids based on poly(ethylene glycol) derivative polymers, joining in these well-known colloids of polystyrene, PMMA, and PNIPAM. The central idea is to synthesize these colloids with copolymerization of poly(ethylene glycol) ethyl ether methacrylate (PEGETH2MA), poly(ethylene glycol) methyl ether methacrylate (PEGMEA), poly(ethylene glycol) acrylate (PEGA) and their derivatives using precipitation polymerization method. The first two components give the low critical solution temperature (LCST) near the physiological temperature while the third component (PEGA) provides a functional group. Under proper chemical compositions and reaction conditions, PEG derivative microgels with a very narrow size distribution may be obtained. As a result, these PEG derivative microgels can be used as building blocks to fabricate hydrogels with colloidal crystal structures. This proposed project consists of five specific aims. The first is to synthesize and characterize PEG derivative microgels that should be monodisperse, thermoresponsive, and with functional groups. The second aim is to synthesize biodegradable PEG derivative microgels by first synthesizing biodegradable PEG-polylactic acid macromer and then using them as crosslinkers for microgels. Self-assembling processes of the PEG derivative microgels will be explored by establishing the relationship between crystallization kinetics with the softness (low mechanical modulus) of the microgels. (Aim 3) Hydrogels with colloidal crystalline structures will be synthesized using PEG derivative microgels as both crosslinkers and as a light diffraction lattice (Aim 4). Aim five will focus on preparation of PEG-microgels-based colloidosomes and build a theoretical model that will describe swelling kinetics of a gel shell such as colloidosomes.NON-TECHNICAL SUMMARY:This proposed project is innovative because if successful, it will lead to a new class of polymer colloids that have thermal responsive properties and monodisperse size distribution. In contrast to polystyrene spheres and PMMA spheres that are hydrophobic, the proposed PEG derivative particles are hydrophilic and have a thermally responsive volume phase transition near the physiological temperature. Different from PNIPAM microgels that are extremely soft in terms of elastic modulus, the PEG derivative microgels will be denser, harder and easier to form a crystalline structure as revealed by the feasibility study. Furthermore, in the past two decades the most research on thermally responsive polymer microgels has focused on PNIPAM and its derivatives. However, the extraordinary thermo-sensitive properties of PNIPAM have not been transferred into a biomedical breakthrough. One of the major hurdles is that PNIPAM monomer is carcinogenic or teratogenic. Thus, finding a biocompatible polymer microgel replacement of PNIPAM will be one of the major advancements in this field. The proposed project will provide direct support for two graduate students and broaden the participation of underrepresented groups. This program will integrate its undergraduate educational efforts with three existing programs that promote research experiences: the Texas Academy of Mathematics and Science, the Ronald F. McNair Post-baccalaureate Achievement Program at UNT, and NSF-UNT REU summer program. From this proposed inter-disciplinary project, both graduate and undergraduate students will gain valuable experimental and analytical skills in the rapidly growing fields of polymers, colloids and nanostructured materials. The basic sciences established in this research will have impacts not only in polymer sciences but also in biomedical technology.

合成单分散聚合物胶体通常是研究自组装过程的第一步，对于纳米结构材料的制造尤其重要。目前可用的聚合物胶体包括聚苯乙烯、聚甲基丙烯酸甲酯（PMMA）和聚-N-异丙基丙烯酰胺（PNIPAM）球及其衍生物。该项目的目标是创建基于聚（乙二醇）衍生物聚合物的新的单分散，热响应聚合物胶体，加入这些众所周知的聚苯乙烯，PMMA和PNIPAM胶体。其核心思想是通过聚乙二醇乙醚甲基丙烯酸酯（PEGETH 2 MA）、聚乙二醇甲醚甲基丙烯酸酯（PEGMEA）、聚乙二醇丙烯酸酯（PEGA）及其衍生物的共聚合，采用沉淀聚合法合成这些胶体。前两个组分提供接近生理温度的低临界溶解温度（LCST），而第三组分（PEGA）提供官能团。在适当的化学组成和反应条件下，可以得到具有非常窄的粒径分布的PEG衍生物微凝胶。 因此，这些PEG衍生物微凝胶可以用作构建块来制造具有胶体晶体结构的水凝胶。该项目包括五个具体目标。首先是合成和表征PEG衍生物微凝胶，应该是单分散的，温敏的，并与功能基团。第二个目标是通过首先合成可生物降解的PEG-聚乳酸大分子单体，然后使用它们作为微凝胶的交联剂来合成可生物降解的PEG衍生物微凝胶。PEG衍生物微凝胶的自组装过程将探索通过建立结晶动力学与微凝胶的柔软度（低机械模量）之间的关系。(Aim 3）将使用PEG衍生物微凝胶作为交联剂和作为光衍射晶格来合成具有胶体晶体结构的水凝胶（目的4）。目的五将专注于制备PEG-微凝胶为基础的胶体体，并建立一个理论模型，将描述溶胀动力学的凝胶壳，如colloidosomes.NON-TECHNICAL摘要：这个拟议的项目是创新的，因为如果成功，它将导致一类新的聚合物胶体，具有热响应性能和单分散的尺寸分布。与疏水性的聚苯乙烯球和PMMA球相反，所提出的PEG衍生物颗粒是亲水性的，并且在生理温度附近具有热响应体积相变。与弹性模量极软的PNIPAM微凝胶不同，PEG衍生物微凝胶将更致密，更硬，更容易形成晶体结构，如可行性研究所揭示的。此外，在过去的二十年中，大多数热响应性聚合物微凝胶的研究集中在PNIPAM及其衍生物。然而，PNIPAM非凡的热敏特性尚未转化为生物医学突破。主要障碍之一是PNIPAM单体具有致癌性或致畸性。因此，寻找一种生物相容的聚合物微凝胶替代PNIPAM将是该领域的主要进展之一。拟议的项目将为两名研究生提供直接支助，并扩大代表性不足群体的参与。该计划将整合其本科教育的努力与三个现有的计划，促进研究经验：得克萨斯州数学和科学学院，罗纳德F。麦克奈尔学士后成就计划在UNT，和NSF-UNT REU夏季计划。从这个拟议的跨学科项目，研究生和本科生将获得宝贵的实验和分析技能，在聚合物，胶体和纳米结构材料的快速增长的领域。 在这项研究中建立的基础科学将不仅在聚合物科学，而且在生物医学技术的影响。