Structure-Property Relationships of Protein-based Block Copolymer Nanocomposites

该项目设想了一个合成生物学的未来，在这个未来中，合成生物学能够生产定制的、生物相容性的、环境友好的粘合剂，这些粘合剂的性能超过了目前合成化学所能达到的。由于最近在重组蛋白基生物材料和纤维素纳米晶体增强纳米复合材料制备方面的突破，这种未来现在成为可能。该团队将开发这些技术，并通过寻找肌腱与骨手术再附着的粘合剂解决方案来证明这些技术，这是一个对公众健康至关重要的问题。例如，在某些人群中，高达94%的肩袖修复失败。通过整合合成生物学、生物材料工程、材料表征、生物力学、界面和粘附等方面的专业知识，该团队将设计和合成这些新型外科粘合剂，具有目前没有生物相容性材料具有的特性。除了通过传统途径进行广泛传播以及对研究生和本科生研究人员的培训和教育之外，这项工作还将与华盛顿大学学校合作研究所合作，通过STEM经验和对当地K-12教师、学生和家庭的教育，将这一新兴领域的知识和发现的兴奋转化为知识。技术摘要：提出的工作将展示一类新的重组蛋白基生物材料的变革潜力，用于需要复杂组合特性的应用。这一结果将决定蛋白质基嵌段共聚物（pbcp）及其纤维素纳米晶体（cnc）纳米复合材料性能的序列-结构性质关系。该项目将通过创建一个通用的平台技术来利用DNA模板和细菌来生产具有生物启发蛋白质基序所需性能的明确定义的嵌段共聚物，从而推进纳米复合水凝胶的设计科学和更广泛的生物材料领域。此外，这项工作将通过开发(1)能够调节纳米填料和聚合物基体链之间相互作用的部分，以及(2)在纳米复合材料力学性能预测中考虑纳米填料表面能、可能的相互作用和聚合物基体再结晶的均质工具，推进纳米复合材料设计领域。项目目标包括合成pbcp，其中每个块具有明确的单体序列和结构，以形成(1)刚性并提供增强强度的结晶域，(2)柔性并提供增强韧性的无定形域，以及(3)允许可调的分子间相互作用和表面粘附的粘附域。合成生物学允许控制共聚物中每个嵌段的长度和序列。通过同时调整CNC表面和PBCP序列的化学性质，可以控制PBCP的性质以及CNC和PBCP之间的相互作用，从而通过开发完全可调的纳米复合材料性质来改变粘合剂的合成。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。

Non-technical Abstract This project envisions a future in which synthetic biology enables the production of tailored, biocompatible, and environmentally friendly adhesives with properties beyond those currently attainable by synthetic chemistry. This future is now possible thanks to recent breakthroughs in the preparation of recombinant protein-based biomaterials and cellulose nanocrystal reinforced nanocomposites. The team will develop these technologies, and demonstrate them by finding adhesive solutions for the surgical reattachment of tendon to bone, a problem of significant importance to public health. For example, as many as 94% of rotator cuff repairs fail in some populations. By assembling expertise in synthetic biology, biomaterial engineering, material characterization, biomechanics, and interfaces and adhesion, the team will design and synthesize these novel surgical adhesives, with properties that no biocompatible material currently has. Beyond broad dissemination through traditional avenues and training and education of graduate and undergraduate researchers, this work will partner with Washington University's Institute for School Partnership to translate knowledge and the excitement of discovery in this emerging area through outreach via STEM experiences and education for local K-12 teachers, students, and families.Technical AbstractThe proposed work will demonstrate the transformative potential of a new class of recombinant protein-based biomaterials for applications requiring a complex combination of properties. The outcome of this will be sequence-structure property relationships that determine the performance of protein-based block copolymers (PBCPs) and their cellulose nanocrystals (CNCs) nanocomposites. This project will advance the science of designing nanocomposite hydrogels and more generally the field of biomaterials by creating a generalizable platform technology for harnessing DNA templates and bacteria to produce well-defined block copolymers with desired properties from bioinspired protein motifs. In addition, this work will advance the field of nanocomposite materials design by developing (1) moieties capable of tunable interactions between nanofillers and polymer matrix chains and (2) homogenization tools that account for nanofiller surface energy and possible interactions and recrystallization of the polymer matrix in the prediction of nanocomposite mechanical properties. Project aims include the synthesis of PBCPs where each block has a well-defined monomer sequence and structure to form (1) crystalline domains that are rigid and provide enhanced strength, (2) amorphous domains that are flexible and provide enhanced toughness, and (3) adhesive domains that allow for tunable intermolecular interactions and adhesion to surfaces. Synthetic biology allows for control of the length and sequence of each block in the copolymer. By simultaneously tuning the chemistry of CNC surfaces and PBCP sequence, PBCP properties and interactions between CNCs and PBCPs can be controlled, thus transforming the synthesis of adhesives through the development of fully tunable nanocomposite material properties.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.