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

技术概述：反应性水凝胶技术目前正在广泛应用，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，它们的功效受到严重限制。这通常是由于大多数体系固有的结构不明确，凝胶基于材料内部空间随机交联，或者在整个样品中分布不均匀的形成不良的固相畴。本次CAREER奖提出的研究活动的最终目标是成功生产出一种新型的高度可膨胀的纳米结构水凝胶，这种水凝胶能够对一系列外部刺激做出复杂而可调的反应。第一代水凝胶将通过利用球状嵌段共聚物两亲体的熔融状态自组装来制造，作为更多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（例如，温度，pH值，光等）连续调整这些凝胶中的溶液和固相的尺寸，几何形状和尺寸分布，所有这些都具有严格的控制。同时，我们的目标是结合内部触发器，可以诱导更剧烈的材料响应外部刺激，如体积、模量或磁导率的快速和不连续变化。将这些想法扩展到非球形形态，有望为实现各向异性膨胀控制的材料提供途径。虽然提出的初步工作侧重于基本水凝胶的合成和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份嵌段共聚物进行合成修饰来整合先进的响应机制。拟议的研究将有助于提高下一代“智能”或响应材料的设计知识，这些材料能够同时产生多种刺激诱导的行为，包括：溶解、膨胀各向异性、连续和非连续膨胀（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：本次CAREER奖提出的研究是针对成功生产新型高吸水性聚合物材料，这种材料具有独特的能力，可以改变其最基本的特性，如形状、大小、韧性和渗透性，直接响应施加的刺激，如紫外线、热量或电场，仅举几例。预计这些材料在先进的药物输送、改善的植入物相容性、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技术上重要的领域产生广泛影响，这些领域的社会生活质量可能受到深刻影响。这些研究活动将与各种能力的学生教育结合起来，努力使有前途的年轻研究人员在学习中有发现的成分。例如，广泛地将本科生作为活跃的研究人员纳入该项目，将结果直接纳入课程课程，并通过全国和世界各地的本科生，研究生和部门研讨会传播结果，使这一前沿研究成为主流学习工具。此外，该职业奖还用于为地区（科罗拉多州和怀俄明州）高中科学教师举办为期一天的年度互动研究研讨会，在研讨会上，纳米技术、生物技术和生物材料方面的最新主题可以与世界专家进行讨论。这些研讨会的目标是为每位教师提供动手材料，将最新的研究带到他们自己的课堂上，这样高中生就能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.