CAREER: Integration of Sophisticated Stimuli-Response Capabilities into Highly-Distensible Nanostructured Hydrogels

技术概述：响应性水凝胶技术目前正被应用于一系列领域，包括组织支架、化学释放剂、生物传感器和人造肌肉。然而，由于无法以可控的方式引入准确和可调的反应机制，它们的有效性受到了严重限制。这通常归因于大多数体系固有的模糊结构，凝胶基于材料中空间随机的交联键，或者形成不佳的固相域，在整个样品中分布不均匀。这一职业奖项中提出的研究活动的最终目标是成功地产生一种新的高度可膨胀的纳米结构水凝胶，能够对一系列外部刺激做出复杂和可调的反应。第一代水凝胶将通过熔融状态自组装形成嵌段共聚两亲分子的球体来制造，作为更高功能材料的极其通用的模板。我们的目标是生产具有集成功能的水凝胶，允许人们通过外部刺激(如温度、pH值、光线等)连续调节这些凝胶中溶液和固相的尺寸、几何形状和尺寸分布，所有这些都是在严格控制的情况下进行的。与此同时，我们的目标是结合内部触发因素，这些内部触发因素可以引起对外部刺激的更剧烈的材料反应，例如体积、模数或区域渗透性的快速和不连续变化。将这些想法扩展到非球形形态，有望为各向异性膨胀控制提供可能的材料。虽然初步工作侧重于基本水凝胶的合成及其固有响应特性的评价，但主要工作将集中在通过在分子水平上对组成嵌段共聚物进行合成修饰来整合先进的响应机制。这项拟议的研究将有助于促进有关设计下一代“智能”或响应性材料的知识，这些材料能够同时产生多种刺激诱导行为，包括：溶解、膨胀各向异性、连续和不连续的膨胀(和收缩)、弯曲(和不弯曲)、可逆自粘、形状恢复和可触发的化学释放。非技术总结：这一职业奖项中提出的研究旨在成功地产生一种新型的高吸水性聚合物材料，这种材料具有独特的能力，可以直接响应应用刺激，如紫外线、热或电场，改变其最基本的特征，如形状、尺寸、韧性和渗透性，仅举几例。这些材料有望在先进的药物输送、改进的植入物兼容性、可降解组织支架、人造肌肉、化学和生物传感器以及生物催化方面具有直接意义。因此，拟议的研究预计将在一些重要的技术领域产生广泛影响，在这些领域，社会生活质量可能会受到严重影响。这些研究活动将在一系列能力方面与学生教育相结合，努力将学习中的发现因素带给有前途的年轻研究人员。例如，广泛吸收本科生作为该项目的积极研究人员，将结果直接整合到课程课程中，并通过全国和世界各地的本科生、研究生和院系研讨会传播结果，使这一尖端研究成为主流学习工具。此外，该职业奖还被用于为地区(科罗拉多州和怀俄明州)高中科学教师开发为期一天的年度互动研究研讨会，在研讨会上，可以与世界专家讨论纳米技术、生物技术和生物材料的最新主题。这些研讨会的目标是为每位教师提供实践材料，使他们能够在自己的课堂上将最新的研究带入生活，这样高中生就能够分享科罗拉多州立大学和世界各地最新研究的兴奋。

TECHNICAL SUMMARY:Responsive hydrogel technologies are currently being pursued in a range of applications, including tissue scaffolds, chemical release agents, biosensors, and artificial muscles. However, their efficacy has been severely restricted by an inability to introduce accurate and tunable response mechanisms in a controlled fashion. This is often attributable to the inherently ill-defined structure of most systems, with gelation based on spatially random cross-links within the material, or poorly formed solid phase domains distributed non-uniformly throughout the sample. The ultimate goal of the research activities proposed in this CAREER award is the successful generation of a new class of highly distensible, nanostructured hydrogels, capable of sophisticated and tunable responses to a range of external stimuli. The first generation of hydrogels are to be fabricated by exploiting the melt-state self-assembly of sphere forming block copolymer amphiphiles, as extremely versatile templates for more highly functioning materials. Our goal is to generate hydrogels with integrated functionality permitting one to continuously tune, through external stimuli (e.g., temperature, pH, light, etc.), the dimensions, geometry, and size distribution of both the solution and solid phases in these gels, all with exacting control. At the same time, we aim to incorporate internal triggers that can induce more drastic material responses to an external stimulus, such as rapid and discontinuous changes in volume, modulus, or domain permeability. Extension of these ideas to non-spherical morphologies is expected to provide access to materials in which anisotropic swelling control is possible. While the preliminary work proposed focuses on the synthesis of the basic hydrogels and evaluation of their inherent response characteristics, the predominance of the work will be focused on the integration of advanced response mechanisms through synthetic modifications to the constituent block copolymers at the molecular level. The proposed research will be instrumental in the advancement of knowledge concerning the design of next generation, "intelligent" or responsive materials, capable of multiple simultaneous stimulus-induced behaviors, including: dissolution, swelling anisotropy, continuous and discontinuous expansion (and contraction), bending (and unbending), reversible self-adhesion, shape recovery, and triggerable chemical release. NON-TECHNICAL SUMMARY:The research proposed in this CAREER award is directed at the successful generation of a new class of super-absorbent polymeric materials that possess the unique capability of changing their most basic characteristics, such as shape, size, toughness, and permeability in direct response to an applied stimulus, such as UV light, heat, or an electric field, to name just a few. These materials are anticipated to have direct implications in advanced drug delivery, improved implant compatibility, degradable tissue scaffolds, artificial muscles, chemical and biological sensors, and biocatalysis. Thus, the proposed research is expected to have broad impact in a number of technologically important areas in which societal quality of life can be deeply affected. These research activities will be integrated with student education in a range of capacities, in an effort to bring the element of discovery in learning to promising young researchers. For example, the extensive inclusion of undergraduate students as active researchers on this project, integration of the results directly into course curricula, and the dissemination of results through undergraduate, graduate, and departmental seminars around the country and world permit this cutting edge research to become a mainstream learning tool. In addition, this CAREER award is also being used to develop annual one-day interactive research workshops for regional (Colorado and Wyoming) high school science teachers, in which recent topics in nanotechnology, biotechnology, and biomaterials can be discussed with world experts. The goal of these workshops is to provide each of the teachers with the hands-on materials to bring the latest research to life in their own classrooms, such that high school students will be able to share the excitement of the latest research at Colorado State University and around the world.