Designer Soft Microparticles for a Changing Environment

专为不断变化的环境而设计的软微粒

• 批准号: 1708729
• 负责人: David Weitz
• 金额: $ 45万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-08-01 至 2020-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1708729&HistoricalAwards=false
• 关键词: Designer; Soft; Microparticles; Changing; Environment

Non-technical AbstractPolymeric particles and capsules with diameters of tens to hundreds of micrometers, similar to the size of a human hair, are extensively used for the encapsulation and protection of chemically or environmentally sensitive active molecules or nanoparticles, with uses, for example, for food and detergent additives, for cosmetics, as well as for drug delivery. During storage and delivery, the encapsulant protects the cargo, and releases it at the desired location, often through some external stimulus that breaks or degrades the encapsulant. Microcapsules, particles with thin shells and large hollow cores, are particularly valuable because only small amounts of encapsulant is needed to protect large amounts of the desired payload. In this project, novel microcapsules are developed with shells that release the capsule content reversibly in response to different external stimuli without shell destruction, leaving the capsule intact for reuse or repeated on-off switching of the release. These capsules are ideal for applications such as waste removal in water, where they can be opened to collect the waste, closed to remove it, and reopened to release the waste in appropriate storage containment. These capsules are obtained from complex emulsions, such as water-cored oil drops, that are fabricated using microfluidic devices with channel architectures of comparable size to the drops. This technology enables precise manufacturing of capsules with control over size, shell thickness, and composition with very low dispersity. The students involved in this project, both undergraduates and graduates, are trained in functional polymer synthesis, microfluidic technology, and materials characterization, giving them a broad set of tools that is indispensable for modern multidisciplinary research in materials science. Technical AbstractEncapsulation of chemically or environmentally sensitive active molecules or nanoparticles is crucial in numerous applications, from food additives, to detergents and drug delivery; traditionally sacrificial encapsulants are used in a one-time, one-way encapsulate-and-release design. A primary aim of this project is to develop and fabricate a new class of dynamic encapsulant systems based on functional polymer microcapsules that exhibit active and reversible interactions with their environment. Microfluidic devices are used to create well-defined multiple emulsion drops of immiscible fluids that form templates for soft encapsulation materials. The physics of the assembly of functional materials in complex emulsions, and the dynamic functionalities of the materials themselves, are investigated, as is the influence of liquid confinement on these processes and properties. An additional aim of the project is to investigate the interactions of these functional polymeric microcapsules with solutes, the environment, and external stimuli for responsive and selective permeability in and out of the capsule. Encapsulation systems with such responsive permeability enable the reversible, on-demand release of actives, and allow the replenishment of actives inside the capsules through triggered uptake and trapping of cargo. This research extends the application of such encapsulants from one-way delivery systems to utilization in purification and separation. An additional objective of this project is the development of designer porous media with controlled mechanical properties to study fundamental mechanisms of the behavior of porous media and multiphase flow within it. These model systems provide insight into processes that are widely practiced but not well understood, including the fracturing of porous media due to pressure shocks, and the effects of polymer solutions on multiphase fluid flow in porous media.

非技术摘要直径为数十至数百微米（类似于人类头发的大小）的聚合物颗粒和胶囊广泛用于封装和保护化学或环境敏感的活性分子或纳米颗粒，例如用于食品和洗涤剂添加剂、化妆品以及药物输送。在储存和运输过程中，密封剂保护货物，并通常通过一些破坏或降解密封剂的外部刺激将其释放到所需位置。微胶囊是具有薄壳和大空心的颗粒，特别有价值，因为只需要少量的密封剂即可保护大量所需的有效负载。在该项目中，开发了带有外壳的新型微胶囊，可响应不同的外部刺激可逆地释放胶囊内容物，而不会破坏外壳，使胶囊完好无损以供重复使用或重复开关释放。这些胶囊非常适合水中废物清除等应用，它们可以打开以收集废物，关闭以清除废物，然后重新打开以将废物释放到适当的存储容器中。这些胶囊是从复杂的乳液（例如水核油滴）中获得的，这些乳液是使用微流体装置制造的，其通道结构与液滴的尺寸相当。该技术能够精确制造胶囊，控制尺寸、壳厚度和分散度极低的成分。参与该项目的学生，无论是本科生还是研究生，都接受了功能聚合物合成、微流体技术和材料表征方面的培训，为他们提供了现代材料科学多学科研究不可或缺的广泛工具。技术摘要化学或环境敏感的活性分子或纳米颗粒的封装在许多应用中至关重要，从食品添加剂到洗涤剂和药物输送；传统上，牺牲密封剂用于一次性、单向封装和释放设计。该项目的主要目标是开发和制造基于功能聚合物微胶囊的新型动态封装系统，该系统与环境表现出主动且可逆的相互作用。微流体装置用于创建边界明确的不混溶流体的多个乳滴，形成软封装材料的模板。研究了复杂乳液中功能材料组装的物理原理以及材料本身的动态功能，以及液体限制对这些过程和性能的影响。该项目的另一个目的是研究这些功能性聚合物微胶囊与溶质、环境和外部刺激的相互作用，以实现胶囊进出的响应性和选择性渗透性。具有这种响应渗透性的封装系统能够实现活性物质的可逆、按需释放，并允许通过触发吸收和捕获货物来补充胶囊内的活性物质。这项研究将此类封装剂的应用从单向输送系统扩展到纯化和分离中的应用。该项目的另一个目标是开发具有受控机械性能的设计多孔介质，以研究多孔介质及其内多相流行为的基本机制。这些模型系统提供了对广泛实践但尚未充分理解的过程的深入了解，包括压力冲击导致的多孔介质破裂，以及聚合物溶液对多孔介质中多相流体流动的影响。

项目成果

Rapid additive-free bacteria lysis using traveling surface acoustic waves in microfluidic channels

• DOI: 10.1039/c9lc00656g
• 发表时间: 2019-12-21
• 期刊: LAB ON A CHIP
• 影响因子: 6.1
• 作者: Lu, Haiwei;Mutafopulos, Kirk;Weitz, David A.
• 通讯作者: Weitz, David A.

Hydrogel micromotors with catalyst-containing liquid core and shell

• DOI: 10.1088/1361-648x/ab0822
• 发表时间: 2019-03
• 期刊: Journal of Physics: Condensed Matter
• 作者: Hong Zhu;S. Nawar;J. Werner;Jinrun Liu;Gaoshan Huang;Y. Mei;D. Weitz;A. Solovev

Hydrogel Microcapsules with Dynamic pH-Responsive Properties from Methacrylic Anhydride

• DOI: 10.1021/acs.macromol.8b00843
• 发表时间: 2018-07
• 期刊: Macromolecules
• 影响因子: 5.5
• 作者: J. Werner;S. Nawar;A. Solovev;D. Weitz

Wetting controls of droplet formation in step emulsification

• DOI: 10.1073/pnas.1803644115
• 发表时间: 2018-09-18
• 期刊: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• 影响因子: 11.1
• 作者: Eggersdorfer, Maximilian L.;Seybold, Hansjorg;Studart, Andre R.
• 通讯作者: Studart, Andre R.

Surfactant Variations in Porous Media Localize Capillary Instabilities during Haines Jumps

• DOI: 10.1103/physrevlett.120.028005
• 发表时间: 2018-01-12
• 期刊: PHYSICAL REVIEW LETTERS
• 影响因子: 8.6
• 作者: Edery, Yaniv;Weitz, David;Berg, Steffen
• 通讯作者: Berg, Steffen