CAREER: Shape Responses of Ultrathin Hydrogel Microcapsules

职业：超薄水凝胶微胶囊的形状响应

• 批准号: 1350370
• 负责人: Eugenia Kharlampieva
• 金额: $ 52.5万
• 依托单位: University of Alabama at Birmingham
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-03-01 至 2019-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1350370&HistoricalAwards=false
• 关键词: CAREER; Shape; Responses; Ultrathin; Hydrogel

TECHNICAL SUMMARY:The goal of this CAREER proposal is to develop a novel class of shape-adaptable materials using pH-sensitive hollow hydrogel microparticles (capsules) of specific shapes, and to gain a fundamental understanding of pH-induced capsule shape transformations. To date, environmental control over materials shape remains a major challenge due to experimental difficulties that hinder integration of stimuli-responsiveness into shaped structures. The key task in this work is to understand how shape responses can be controlled by varying capsule geometry, dimensions, chemical structure, and thickness of hydrogel wall. The objectives of this project are: (i) to develop synthesis of hydrogel capsules of various shapes using a layer-by-layer approach; (ii) to explore pH-triggered dimensional and shape transformations in the shaped capsules; and (iii) to investigate pH-triggered changes in capsule mechanical properties and permeability. In this project a series of pH-sensitive anionic and cationic copolymers bearing cross-linkable amino groups will be synthesized and assembled into ultrathin hydrogel films and shape-specific hydrogel capsules. The effects of hydrogel composition, thickness, and stiffness as well as capsule geometry and dimensions on pH-triggered volume transitions and on the related capsule physical properties, including wall swelling/shrinkage, capsule size/shape transformations, mechanical properties, and permeability will be studied. Fundamental correlation between complex shapes and physical and chemical properties will be explored using a combination of in situ techniques such as ATR-FTIR, scattering techniques, ellipsometry, optical and electron microscopy, and nanoindentation. The knowledge obtained in the proposal can be used in controlling size- and shape-transition phenomena in microgels and multilayer capsules. NON-TECHNICAL SUMMARY:This project on creation of shape-transformable hollow particles (capsules) offers prospects for developing materials with novel actuation characteristics having applications for controlled drug delivery, tissue engineering, and pH-regulating transport in microfluidic devices. These structures may have unique properties as compared to simple spheres including shape-guided interactions, a greater stability in flow, and shape-directed flow behavior and cellular uptake. The educational aspect of this project is to develop a polymer sciences program at U. Alabama Birmingham (UAB) promoting learning and research opportunities from the high school through the graduate level. The program will combine elements of traditional polymer chemistry with developing awareness of the needs of the UAB biomedical research community for specialized polymers. The program will have a strong influence on education in the field in the Southeast, with potentially significant social and economic impact. High school, undergraduate, and graduate students including underrepresented minorities will be trained in modern aspects of polymer science including state-of-the-art synthetic and analytical methods and intensive multidisciplinary collaborations throughout and beyond UAB. Educational and outreach activities involve developing new B.S. and Ph.D. programs in polymer science at UAB and creating "PolymerBridge" to enhance the impact on and to increase the opportunities for underrepresented minorities in polymer science. "PolymerBridge I" will be designed for 11-12th graders with instructor-developed demonstrations and include hands-on lab work, while "PolymerBridge II" will target high school science and chemistry teachers.

技术概述：本CAREER提案的目标是使用特定形状的pH敏感中空水凝胶微粒（胶囊）开发一类新型形状适应性材料，并对pH诱导的胶囊形状转变有基本了解。到目前为止，环境控制材料的形状仍然是一个重大挑战，由于实验困难，阻碍了整合的刺激响应到形状的结构。这项工作的关键任务是了解如何通过改变胶囊的几何形状，尺寸，化学结构和水凝胶壁的厚度来控制形状响应。该项目的目标是：（i）使用逐层方法开发各种形状的水凝胶胶囊的合成;（ii）探索成形胶囊中pH触发的尺寸和形状转变;以及（iii）研究胶囊机械性能和渗透性的pH触发变化。在本项目中，将合成一系列带有交叉氨基的pH敏感性阴离子和阳离子共聚物，并将其组装成水凝胶膜和形状特定的水凝胶胶囊。将研究水凝胶组成、厚度和刚度以及胶囊几何形状和尺寸对pH触发的体积转变和相关胶囊物理性质（包括壁溶胀/收缩、胶囊大小/形状转变、机械性质和渗透性）的影响。 复杂的形状和物理和化学性质之间的基本相关性将使用原位技术，如ATR-FTIR，散射技术，椭圆偏振，光学和电子显微镜，和纳米压痕的组合进行探索。在该建议中获得的知识可用于控制微凝胶和多层胶囊中的尺寸和形状转变现象。非技术总结：这个关于形状可转换中空颗粒（胶囊）的项目为开发具有新型致动特性的材料提供了前景，这些材料可用于微流体装置中的受控药物递送、组织工程和pH调节运输。与简单的球体相比，这些结构可能具有独特的性质，包括形状引导的相互作用、更大的流动稳定性以及形状引导的流动行为和细胞摄取。该项目的教育方面是在美国大学发展一个高分子科学项目。亚拉巴马伯明翰（UAB）促进从高中到研究生阶段的学习和研究机会。该计划将联合收割机传统的聚合物化学元素与发展的UAB生物医学研究社区的专业聚合物的需求意识相结合。该计划将对东南部地区的教育产生重大影响，并可能产生重大的社会和经济影响。高中，本科和研究生，包括代表性不足的少数民族将在聚合物科学的现代方面进行培训，包括最先进的合成和分析方法以及UAB内外的密集多学科合作。 教育和推广活动涉及开发新的B.S.和博士在UAB的聚合物科学计划，并创建“聚合物桥”，以提高对聚合物科学的影响，并增加少数民族的机会。 “PolymerBridge I”将为11- 12年级的学生设计，带有自动驾驶仪开发的演示，包括动手实验室工作，而“PolymerBridge II”将针对高中科学和化学教师。