Relaxation dynamics in biological fiber bundles

纤维束广泛存在于自然界中。它们促进了多种生物功能，并表现出不寻常的机械性能。细胞生物学中纤维束的一个例子是微管，它参与许多细胞功能。微管是管状的，由小的蛋白质细丝形成，其相互作用决定了整个微管的力学。最近的研究提供了证据表明，这种特定的分子结构导致了意想不到的机械性能，其中最重要的是，随着它们变长，它们变得更硬，不能弯曲。这一发现也表明，分子结构在很大程度上决定了弯曲微管松弛到平衡状态的速度。 因此，一个系统的研究是必要的，以解决分子结构之间的相互作用，力学和动力学性能在很宽的范围内的长丝长度。 在拟议的研究中，将用高分辨率光学显微镜分析微管自然发生的弯曲变形的松弛，并与考虑微管分子结构的理论模型进行比较。这项研究对材料科学和工程非常重要，因为这些知识可以用来设计具有新机械性能的材料。更一般地，将获得对细胞中的多功能纤维材料的更好理解。 该项目将使学生接触到材料科学与工程，理论物理，物理化学和分子生物学等不同科学领域之间的丰富相互作用，从而以跨学科的方法教育他们进行研究。

Fiber bundles are widely found in nature. They facilitate a multitude of biological functions and exhibit unusual mechanical properties. An example of a fiber bundle in cell biology is the microtubule which is involved in many cell functions. Microtubules are tubular-shaped, formed of small protein filaments whose interactions determine the mechanics of the overall microtubule. Recent studies have provided evidence that this specific molecular architecture leads to unexpected mechanical properties, the most important of which is that they become stiffer against bending as they grow longer. This finding also suggests that the molecular architecture largely determines how fast a bent microtubule relaxes to its equilibrium state. Thus, a systematic study is needed to address the interplay between molecular architecture, mechanics, and dynamical properties over a wide range of filament lengths. In the proposed research, the relaxation of naturally occurring bending deformations of microtubules will be analyzed with high-resolution light microscopy and compared with theoretical models that take the molecular architecture of microtubules into account. The research will be important for material science and engineering as the knowledge can be used to design materials with novel mechanical properties. More generally a better understanding of multifunctional fiber materials in cells will be obtained. The project will expose students to a rich interplay between scientific fields as diverse as material science and engineering, theoretical physics, physical chemistry, and molecular biology, thereby educating them in an interdisciplinary approach towards research.