Comparative biomechanics of intermediate filaments

仿生学是一个不断发展的科学领域，它从生物结构和过程中获得灵感，用于设计新产品。最著名的仿生成功故事是Velcro®，它的灵感来自于小钩子，可以让动物在动物皮毛上搭便车。在我的实验室进行的仿生研究主要集中在由生物体制成的结构材料上，这些材料可能会激发具有独特和有用特性的新合成材料的发明。参加我的博士在一项研究中，我研究了一种纤维材料，这种材料出现在八目鳗的防御粘液中，八目鳗是一种底栖海洋食腐动物。我发现，这些纤维虽然在天然状态下柔软而有弹性，但可以很容易地加工成具有类似蜘蛛丝特性的纤维，蜘蛛丝以其上级强度和韧性而闻名。这些实验导致了一项专利申请（目前正在审查中），并为一组称为“中间丝”（或IF）的纤维蛋白质的结构和性质打开了一扇窗户。这些纳米级的蛋白质丝出现在粘液丝中，构成了大多数动物细胞骨架的重要组成部分。它们还形成了哺乳动物所形成的称为“角蛋白”的更熟悉的材料，其中包括皮肤的柔软外层和较硬的结构，如头发，指甲和角。通过研究盲鳗粘液丝，它由几乎纯的IF束组成，我能够制定一个详细的模型，可以解释动物使用IF制造的材料的巨大多样性。该模型对细胞和角蛋白中IFs的行为进行了几项预测。本文提出的研究的短期目标是通过检查一些最关键的预测来测试和改进模型。为此，我们将使用各种基于IF的方便材料，包括八目鳗粘液丝、神经、马蹄和鲸鱼须鲸。本研究的长期目标是提炼出IF基材料的一些设计原则，并将其应用于工业材料的设计，以提供生态可持续性和上级性能。

Biomimetics is a growing scientific field that takes inspiration from biological structures and processes for the design of novel products. The most famous biomimetic success story is Velcro®, which was inspired by the tiny hooks that allow burrs to hitch a ride on animal fur. The biomimetic research carried out in my lab focuses on structural materials made by organisms that could potentially inspire the invention of new synthetic materials with unique and useful properties. For my Ph.D. research, I worked on a fibrous material that occurs within the defensive slime of the hagfish, a bottom-dwelling marine scavenger. I discovered that these fibres, although soft and stretchy in their native state, could be easily processed into fibres with properties similar to spider silk, which is renowned for its superior strength and toughness. These experiments led to a patent application (which is currently under examination), and also opened a window into the structure and properties of a group of fibrous proteins called "intermediate filaments" (or IFs). These nano-scale protein filaments occur in slime threads and make up an important part of the cytoskeleton of most animal cells. They also form the bulk of the more familiar materials made by mammals called "keratins," which include the soft outer layer of skin and harder structures like hair, nail, and horn. Working with hagfish slime threads, which consist of nearly pure bundles of IFs,  I was able to formulate a detailed model that can explain the large diversity of materials that animals make using IFs. This model makes several predictions about the behavior of IFs in cells and keratins. The short-term goal of the research proposed here is to test and refine the model by examining some of its most critical predictions. To do this, we will use a variety of convenient materials that are based on IFs, including hagfish slime threads, nerves, horse hoof, and whale baleen. The long-term aim of this research is to distill out some of the design principles of IF-based materials, and apply them to the design of industrial materials that deliver both ecological sustainability and superior performance.