Collaborative Research: Controlling Microstructure in Resilin-based Hydrogels: Linking Microscale Mechanical Properties to Behavior

摘要非技术性：活生物体中的弹性蛋白质为皮肤和肌肉等组织提供出色的机械性能，并且通常存在于提供机械增强的异质结构中。因此，能够生产具有特定结构的弹性体材料的材料工程方法在保护材料、药物输送和再生医学等应用领域具有巨大的潜力。PI用于生产这种材料的方法采用节枝弹性蛋白，这是一种昆虫蛋白，具有报道的最佳弹性体特性;节枝弹性蛋白能够在很大程度上变形并完全恢复其原始形状。PI将使用具有特定机械和生物功能的节枝弹性蛋白样蛋白质，并制造包含这些蛋白质和常用合成聚合物的材料。利用光引发化学反应的简单处理方案将用于生成不同组成和可预测结构的混合材料。新的表征方法将用于表征各个域的机械性能，并确定这类软材料的结构-功能关系。 该计划的研究不仅有可能影响能源和医学的社会需求，而且还可能影响各种年龄和经验的学生的教育活动。一系列的研讨会和学生发起的活动，其中PI将参与，将有助于转移该计划的概念到biomaterials technologies. Technical：许多方法来生成水凝胶的3D异质性，使用聚合物为基础的微粒复合材料已显着的兴趣，给予了许多机会，工程粒度，表面积和化学。因此，开发简单的一步法来产生微结构蛋白质-聚合物基质将为系统研究提供显着的优势，使异质材料。我们建议利用高弹性多肽节枝弹性蛋白（RLP）溶液的良好相分离，形成微结构水凝胶。RLP表现出出色的弹性体和物理化学性质，这将促进所得到的材料的实用性，特别是在模型的开发，以了解软水凝胶中的能量耗散。PI将使RLP官能化，使得它们能够进行光引发的交联，并且将绘制RLP和合成聚合物溶液的相分离。该基本信息将允许PI确定用于将溶液光交联成具有限定组成和机械性质的域的微结构水凝胶的适当组成和加工条件。RLP的两种不同的化学修饰将允许PI探测域的局部机械性质和域对水凝胶变形的影响。水凝胶的微观结构将通过显微镜方法表征，而机械性能将通过一套AFM、空化流变学、小应变接触力学、钝穿刺力学和体振荡流变学表征。鉴于水凝胶材料的目标应用和广泛使用的财富，提出的研究将在长期推进微结构弹性体水凝胶在应用中的使用，如能量存储，保护装置，药物输送和再生医学。 研究所将为中学至研究生程度的学生举办一系列工作坊和活动，以促进这些概念转化为技术应用。

ABSTRACT Non-technical:Elastomeric proteins in living organisms provide outstanding mechanical properties to tissues such as skin and muscle, and generally exist in heterogeneous structures that provide mechanical reinforcement. Materials engineering approaches that enable the production of elastomeric materials with defined structures would thus have enormous potential in applications ranging from protective materials, drug delivery, and regenerative medicine. PIs approaches for producing such materials employ resilin, an insect protein that has among the best elastomeric properties reported; resilins are able to deform to a large extent and completely recover their original shape. PIs will use resilin-like proteins that are designed with specific mechanical and biological function and make materials that comprise these proteins and commonly employed synthetic polymers. Simple processing protocols with light-initiated chemistries will be used to generate hybrid materials of different compositions and predictable structures. Novel characterization methods will be used to characterize the mechanical properties of individual domains and determine structure-function relationships in this class of soft materials. The research in this program has the potential to not only impact societal needs in energy and medicine, but also educational activities for students of a variety of ages and experience. A series of workshops and student-initiated activities, in which the PIs will participate, will help transfer concepts of this program into biomaterials technologies.Technical:Of many approaches to generate 3D heterogeneity in hydrogels, the use of polymer-based microparticle composites has been of significant interest, given the many opportunities to engineer particle size, surface area, and chemistry. The development of simple, one-step methods to generate microstructured protein-polymer matrices would thus offer significant advantages for making heterogeneous materials for systematic study. We propose to exploit the well behaved phase separation of solutions of the highly elastomeric polypeptide resilin (RLP), to form microstructured hydrogels. The RLPs exhibit outstanding elastomeric and physicochemical properties that will advance the utility of the resulting materials, particularly in the development of models to understand energy dissipation in soft hydrogels. The PIs will functionalize RLPs so that they are competent for photo-initiated crosslinking, and will map the phase separation of RLP and solutions of synthetic polymers. This fundamental information will allow PIs to identify appropriate compositions and processing conditions for photocrosslinking the solutions into microstructured hydrogels that have domains of defined compositions and mechanical properties. Two distinct chemical modifications of the RLPs will allow PIs to probe the local mechanical properties of the domains and the impact of the domains on hydrogel deformation. The microstructure of the hydrogels will be characterized via microscopy methods, while the mechanical properties will be characterized via a suite of AFM, cavitation rheology, small-strain contact mechanics, blunt puncture mechanics, and bulk oscillatory rheology. Given the wealth of target applications and the widespread use of hydrogel materials, proposed studies will in the long term advance the use of microstructured elastomeric hydrogels in applications such as energy storage, protective gear, drug delivery, and regenerative medicine. PIs will facilitate the transfer of these concepts into technological applications by hosting a series of workshops and activities for students from the secondary to postgraduate levels.