Self-Assembly of Shape-Defined Micro-Hydrogels: Top-Down Meets Bottom-Up

形状限定的微水凝胶的自组装：自上而下与自下而上的相遇

• 批准号: 2106158
• 负责人: Carson Bruns
• 金额: $ 45.58万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-01 至 2025-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2106158&HistoricalAwards=false
• 关键词: Self; Assembly; Shape; Defined; Micro

Nature uses a genetic code to dictate the structures of proteins which, in turn, underpin their functions. However, there is no analog to a genetic code when fabricating synthetic materials. The goal of this project is to create a platform for fabricating materials by assembling soft, polymeric microparticles (particles whose sizes are in the 1-1000 micrometer range) with specific shapes into precisely controlled arrangements. The research idea is that that the molecular information necessary to guide the assembly of the polymeric microparticles can be embedded into the particles themselves. The particles will be formed in a microfluidic system equipped with flow lithography, which is a particle synthesis method for fabricating microparticles by exposing polymers to UV light under precise control. Then, the assembly of the particles into structures will be guided by molecules that are patterned onto the microparticle surfaces. Once established, the platform could be used to construct a variety of innovative structures, such as healable and recyclable tissue-mimetic materials, self-assembled micromachines that harvest waste energy, or soft micro-robots that execute complex tasks in biological environments. To broaden participation in STEM research, the project will support several research and education experiences for underrepresented high school and undergraduate students in collaboration with campus organizations.Programmable self-assembly on the mesoscale is limited to periodic lattices, one-dimensional chains, and small high-symmetry clusters. It is not yet possible to program the self-assembly of particles at the level of sophistication that is achieved in biology or using certain top-down approaches such as 3-D printing. This dearth of methodology limits bottom-up access to anisotropic or highly detailed structures. Despite the emergence of many preparation methods and applications of shape-defined microgels, research on their hierarchical self-assembly into ordered superstructures is limited. Using custom-built flow lithography devices, researchers on this project will control how various functional molecule pairs (e.g., charge-pairing and host-guest motifs) are localized within sequence-defined, one-dimensional and shape-defined two-dimensional polymer microgels. This synthetic method will encode information that governs where and how the particles interact and how they respond to stimuli. The assemblies will be large enough for direct observation in a microscope, facilitating the development of an empirical framework to understand and predict the information-structure-property-behavior relationships. This combination of top-down and bottom-up fabrication techniques will enable a versatile strategy for scaling up molecular-level work to the mesoscale and beyond, the high-throughput synthesis of complex geometries for soft colloids, and a more diverse library of motifs and stimuli for building and actuating soft micro-machines.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

大自然使用遗传密码来决定蛋白质的结构，而蛋白质的结构反过来又支撑着它们的功能。然而，在制造合成材料时，没有类似的遗传密码。该项目的目标是通过将具有特定形状的软聚合物微粒（尺寸在1-1000微米范围内的颗粒）组装成精确控制的排列来创建制造材料的平台。研究思路是，引导聚合物微粒组装所需的分子信息可以嵌入到颗粒本身中。这些颗粒将在配备有流动光刻的微流体系统中形成，流动光刻是一种通过在精确控制下将聚合物暴露于UV光来制造微粒的颗粒合成方法。然后，颗粒组装成结构将由在微粒表面上形成图案的分子引导。一旦建立，该平台可用于构建各种创新结构，例如可修复和可回收的仿组织材料，收集废物能量的自组装微机器，或在生物环境中执行复杂任务的软微机器人。为了扩大STEM研究的参与度，该项目将与校园组织合作，为代表性不足的高中生和本科生提供多项研究和教育经验。中尺度上的可编程自组装仅限于周期性晶格、一维链和小的高对称性集群。目前还不可能在生物学或使用某些自上而下的方法（如3D打印）实现的复杂水平上对粒子的自组装进行编程。 这种方法的缺乏限制了自底向上访问各向异性或高度详细的结构。尽管出现了许多制备方法和形状确定的微凝胶的应用，其分级自组装成有序的超结构的研究是有限的。使用定制的流动光刻设备，该项目的研究人员将控制各种功能分子对（例如，电荷配对和主客体基序）定位在序列限定的一维和形状限定的二维聚合物微凝胶内。这种合成方法将编码信息，这些信息控制粒子在何处以及如何相互作用，以及它们如何对刺激做出反应。这些组件将足够大，可以在显微镜下直接观察，从而促进经验框架的发展，以理解和预测信息-结构-属性-行为的关系。这种自上而下和自下而上的制造技术的结合将实现将分子水平的工作按比例扩大到中尺度及更高尺度的多功能策略，高通量合成软胶体的复杂几何形状，以及更多样化的图案和刺激库，用于构建和驱动软微-该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。