CAREER: Designing Microscale, Shape-Morphing Liquid Crystal Elastomers as Tissue Adhesives

职业：为植入式微机械系统设计微尺度、变形液晶弹性体非技术摘要该职业奖由材料研究部生物材料项目授予达拉斯德克萨斯大学，旨在为植入式微机械系统设计和表征可变形液晶弹性体。液晶弹性体是一种橡胶材料，可以根据环境的变化从一种形状可逆地改变为另一种形状。这种形状的改变不需要外部电源和控制设备，这在植入式医疗设备中特别有用，因为水会破坏电路，电池难以充电，而且空间有限。这项研究成果将使液晶弹性体的合成和制造成为可能，其尺寸比人的头发还小，可以在接近体温时弯曲、拉伸或扭曲。这些小结构将能够穿透组织，随后的形状变化将使合成材料与柔软、潮湿和活动的人体组织具有很强的附着力。这一新策略将解决国家对改进组织粘接剂的关键需求。例如，许多常见的治疗方法，如疝气修复，需要合成材料粘附在软组织上，而粘附失败会导致医疗保健相关成本和疼痛的增加。这些智能材料也将成为向下一代科学家和工程师展示基本科学概念的有力工具。技术摘要：本研究将实现利用微尺度液晶弹性体的可编程形状变化来设计可生物降解的物理胶粘剂。微针阵列穿透软组织，然后进行控制形状的变化，以提高组织的粘附性。液晶弹性体的巨大、可编程和可逆的形状变化使这些材料成为设计活性微结构的理想候选材料。这项工作将克服目前阻碍液晶弹性体在生物医学应用中使用的三个关键限制：1)诱导这些材料形状变化的温度太高，无法用于生物医学应用；2)这些材料的生物降解性是不受控制的；3)形状变化难以在3D微尺度结构中编程。该奖项支持液晶弹性体化学和后处理策略的发展，以调整转变温度和生物降解性。此外，该奖项使微成型技术能够在经历复杂形状变化的3D微结构中处理这些材料。这些活性微结构的特点是能够在软组织上产生机械粘附，从而抵抗拉伸和剪切载荷。研究活动将与小学、中学和大专学生的互动相结合，以帮助培养下一代STEM毕业生。将创建和评估基于设计的学习模块，通过构建智能材料和医疗设备来教授化学和物理的基本概念。该奖项反映了美国国家科学基金会的法定使命，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。

CAREER: Designing Microscale, Shape-Morphing Liquid Crystal Elastomers for Implantable Micromechanical Systems Non-technical abstractThis CAREER award by the Biomaterials Program in the Division of Materials Research, to the University of Texas at Dallas, is to design and characterize shape-changing liquid crystal elastomers for implantable micromechanical systems. Liquid crystal elastomers are rubbery materials that can reversibly change from one shape to another in response to changes in their environment. This shape change occurs without requiring external power and control equipment, which is particularly useful in implantable medical devices where water can disrupt circuitry, batteries are difficult to charge, and space is limited. This research effort will enable the synthesis and fabrication of liquid crystal elastomers, with dimensions smaller than a human hair, which bend, stretch, or twist near body temperature. These small structures will be able to penetrate tissue and the subsequent shape change will enable strong adhesion of synthetic materials to soft, wet, and moving tissues of the human body. This new strategy will address a critical national need for improved tissue adhesives. For example, many common treatments, such as hernia repair, require synthetic materials to adhere to the soft tissue, and adhesion failure leads to increased healthcare-related costs and pain. These smart materials will also serve as powerful tools to demonstrate basic scientific concepts to the next generation of scientists and engineers. Technical abstractThe proposed work will enable the design of biodegradable physical adhesives using the programmed shape change of microscale liquid crystal elastomers. Microneedle arrays that penetrate soft tissue and then undergo controlled shape change to enhance tissue adhesion are envisioned. The large, programmable, and reversible shape change of liquid crystal elastomers make these materials ideal candidates for the design of active microstructures. This work will overcome three critical limitations currently preventing the use of liquid crystal elastomers in biomedical applications: 1) the temperatures that induce shape change of these materials are too high for use in biomedical applications, 2) the biodegradability of these materials is uncontrolled, and 3) the shape change is difficult to program in 3D microscale structures. This award supports development of liquid crystal elastomer chemistries and post-processing strategies to tune transition temperatures and biodegradability. Furthermore, this award enables micromolding techniques to process these materials in 3D microstructures that undergo complex shape change. These active microstructures will be characterized for the ability to create mechanical adhesion to soft tissue that resists both tensile and shear loading. Research activities will be coupled to primary, secondary, and post-secondary student interactions, to help train the next generation of STEM graduates. Design-based learning modules will be created and assessed that teach fundamental concepts in chemistry and physics through the constructs of smart materials and medical devices.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.