From Genes to Gels: Programming the Physical Properties of Artificial Protein Hydrogels

非技术：该奖项由加州理工学院材料研究部生物材料项目颁发，旨在探索设计坚韧、柔软、蛋白质基材料的新策略。我们感兴趣的材料是水凝胶，一种被水高度膨胀的聚合材料。就像动植物的软组织一样，水凝胶表现出广泛的有趣和有用的特性，包括——最重要的——通过改变形状和体积来响应化学和物理信号的能力。但是合成水凝胶不是很坚韧；在许多情况下，不需要太多的能量就能使它们失效。这个项目利用基因工程的力量来设计新的基于蛋白质的水凝胶，这种水凝胶显示出更高的韧性。人工基因用于编码蛋白质序列，在变形时耗散能量；然后，耗散的能量不再可用，导致材料在使用过程中失效。韧性的提高将导致水凝胶在药物和基因传递、组织工程、细胞包封和粘附方面的新应用。该项目为研究生和本科生提供了重要的教育、培训和拓展机会。此外，该项目的研究活动将与加州理工学院的“基因到凝胶”项目相结合，该项目将向高中生和教师介绍生物科学和材料科学之间的界面研究。这些来自大洛杉矶地区公立学校的高中生和教师预计将从这次实践研究经验中受益匪浅。技术：水凝胶是高含水量的交联聚合物网络。虽然它们的物理和化学性质差别很大，但大多数水凝胶形成柔软、有弹性的材料。这使它们成为软组织工程和体外细胞培养中替代天然细胞外基质的理想人选。但是，使水凝胶在这些应用中具有吸引力的相同性质也可能导致脆性材料。该项目利用基因工程对人工蛋白质水凝胶的组装进行编程，重点是提高韧性。遗传方法提供了一种控制链序列的水平，这在传统的聚合物合成中仍然是不可能的，序列变化的便利性允许对决定凝胶韧性的分子过程进行详细的探索。在这项工作中开发的增韧策略将建立通用的、广泛有用的方法来设计坚韧、柔韧的材料。该项目吸引了从高中到研究生的各个层次的学生，包括来自洛杉矶盆地各地高中的科学教师。

Non-Technical: This award by the Biomaterials program in the Division of Materials Research to California Institute of Technology is to explore new strategies for the design of tough, soft, protein-based materials. The materials of interest are hydrogels, polymeric materials that are highly swollen by water. Like the soft tissues of plants and animals, hydrogels exhibit a wide range of interesting and useful properties, including - most importantly - the capacity to respond to chemical and physical signals by changing shape and volume. But synthetic hydrogels are not very tough; in many cases it does not require much energy to cause them to fail. This project exploits the power of genetic engineering to design new protein-based hydrogels that show improved toughness. Artificial genes are used to encode protein sequences that dissipate energy upon deformation; the dissipated energy is then no longer available to cause the material to fail while in use. Improvements in toughness will lead to new applications of hydrogels in drug and gene delivery, tissue engineering, cell encapsulation and adhesion. The project provides important educational, training and outreach opportunities for graduate and undergraduate students. Additionally, the research activities of this project will be integrated with the "Genes to Gels," program at Caltech that will introduce high school students and teachers to research at the interface between the biological sciences and materials science. These high school students and teachers from the public schools in the greater Los Angeles area are expected to gain greatly with this hands-on research experience. Technical: Hydrogels are crosslinked polymer networks of high water content. While their physical and chemical properties vary widely, most hydrogels form soft, elastic materials. This makes them excellent candidates to replace the natural extracellular matrix in soft tissue engineering and in vitro cell culture. But the same properties that make hydrogels appealing for these applications can also lead to brittle materials. This project uses genetic engineering to program the assembly of artificial protein hydrogels, with a specific focus on improving toughness. Genetic methods provide a level of control of chain sequence that is still not possible in conventional polymer synthesis, and the ease of sequence variation allows detailed exploration of the molecular processes that determine gel toughness. The toughening strategies developed in this work will establish general, broadly useful approaches to the design of tough, pliable materials. The project engages students at all levels from high school to graduate study, and includes science teachers drawn from high schools throughout the Los Angeles basin.