WISS: Why Is Silk Spun? Integrating bio-rheology with advanced spectroscopic techniques

丝绸作为生物材料的个性甚至在它成为纤维之前就已经确立了。与任何其他生物聚合物不同，丝绸不像头发、骨骼和羽毛那样在几个月甚至几年的时间里缓慢生长，而是通过纺纱在几秒钟内产生。虽然这种方法在自然界是独一无二的，但它是人类熟悉的领域，因此丝绸作为一种生物聚合物模型具有很高的相关性；它是在熟悉的溶剂纺丝工艺中制造的，进而可以进行实验室研究。因此，我们现在有了发问的背景和方法；鉴于自然界已经有了纳米级材料沉积的现有机制，为什么会出现一种全新的生物制造过程，它是如何工作的，我们可以从中学到什么？这项拟议的研究旨在调查为什么蚕丝蛋白在生物材料中是独一无二的，因为它已经针对流动加工(即纺纱)进行了优化。这项拟议的工作将建立在先前关于丝蛋白在溶液中的结构的工作的基础上，但将引入新的集成流变光谱工具来动态研究这些系统。具体地说，我们的研究目标是：(I)开发、改进和扩展我们对蚕丝蛋白质的大宗流变学测量；(Ii)通过光谱分析来确定蚕丝蛋白质在流动状态下的结构变化；(Iii)观察蚕丝蛋白质在流动状态下的变性和聚集动力学以及多尺度层次结构的发展；(Iv)为博士研究生提供物理科学和生命科学相结合的多学科培训。该项目提供了无与伦比的机会，让我们了解一种新型生物加工技术的起源，该技术对我们自己的工业生产具有直接影响，并且将在广泛的不同条件和具有优异性能的应用中运行。这项研究的结果将挑战我们对蛋白质为什么折叠和聚集的理解，涉及从进化生物学到软凝聚态物理学的问题。

Silk's individuality as a biological material is established before it even becomes a fibre. Quite unlike any other biopolymer, silk is not grown slowly over months and years like hair bone and feathers, but produced in a matter of seconds through the act of spinning. Whilst this approach is unique in the natural world, it is familiar territory to man, thus making silk highly relevant as a model biopolymer; it is fabricated in a familiar solvent-spinning process, which in turn is accessible to laboratory investigation. Hence we now have the background and means to ask; given that Nature already had existing mechanisms for nano-scale deposition of materials, why was a fundamentally new biofabrication process evolved, how does it work and what can we learn from it? The proposed study sets out to investigate why silk proteins are unique amongst biological materials in having been optimised for flow processing (i.e. spinning). The proposed work will build on previous work on silk protein structures in solution but will introduce novel integrated rheo-spectroscopic tools to study these systems dynamically. Specifically our research aims to: (i) develop, refine and extend our bulk rheological measurements on silk proteins; (ii) spectroscopically determine silk protein structural changes under flow; (iii) observe silk protein denaturation and aggregation kinetics under flow and the development of multiscale hierarchical structures and - importantly - (iv) offer multidisciplinary training for a D.phil student at the interface of the physical and the life sciences.This project offers the unparalleled opportunity to understand the origins of a novel bioprocessing technology that has direct implications for our own industrial production of polymers that are environmentally benign and will operate in a wide range of different conditions and applications with exceptional properties. The outcome of this research will challenge our understanding of why proteins fold and aggregate, addressing questions from evolutionary biology to soft condensed matter physics.