Learning from the cytoskeleton for the development of active materials
Jülich, 6 August 2020. Jülich researchers have developed models and techniques for computer simulations to investigate dynamic processes that occur, for example, in the internal machinery of cells. The methods provide a better understanding of the microscopic processes involved and could be helpful in the development of tailor-made active materials. These materials adapt their properties independently to changing environmental conditions and possess dynamically controllable properties. This enables them to be used in a wide range of applications, such as the development of self-healing materials, materials that reversibly contract and then relax again, and materials that can mix the chemicals they contain.
The cytoskeleton is a dynamic network inside the cells of animals, plants and fungi. On the one hand, its role is to stabilize the cell and its shape, and on the other, to enable active movement of the cell as a whole, movement and transport within the cell, as well as signal transmission between cells. The cytoskeleton consists of filamentous protein polymers, which can be dynamically assembled and dismantled, and are connected to each other by crosslinks. Passive crosslinks stabilize static network structures, while active crosslinks, in particular so-called motor proteins, promote sustained movement and the self-organization of the protein filaments by consuming energy.
In addition to their enormous biological importance, mixtures of filamentous and motor components are also relevant from a physical point of view, as they can form so-called “active nematics”. These are materials that resemble miniaturised shoals of fish, in which fish swim closely side by side in small groups, but also through and in between each other.
In the groups, called “domains” in the case of materials, the individual fishes/filaments arrange themselves predominantly nematically, i.e. parallel or anti-parallel to each other. These domains are constantly moving, changing direction, splitting up and merging with other domains – as long as there is fuel available. “A microscopic understanding of this dynamic process in the cells can help develop strategies for novel engineering materials,” explains Dr Gerrit Vliegenthart from the Institute of Biological Information Processing.
The physicist and his Jülich colleagues are developing computer simulation models and techniques to study the structure and dynamics of complex fluids, soft matter and biological systems. In contrast to previously used microscopy techniques and modelling approaches, which focus on length scales far beyond the diameters of filaments and motor proteins, they are able to resolve the underlying mesoscopic structure of domains and the complex interaction between microscopic parameters and the resulting mesoscopic and macroscopic behaviour. This allows questions to be answered, such as: Do the filaments bend under the influence of microscopic forces? How many motor proteins per filament are needed to stabilize the dynamically chaotic, active-nematic state? How long does it typically take to reorganize the domains? Answering such questions is essential for understanding cell movement and designing active materials.
Original publication:
Gerard A. Vliegenthart at al.; Filamentous active matter: Band formation, bending, buckling, and defects; Science Advances 22 Jul 2020: Vol. 6, no. 30, eaaw9975,
DOI: 10.1126/sciadv.aaw9975
About the videos: Two video simulations by Jülich researchers show how apparently chaotic yet ordered protein filaments that form the cytoskeleton of cells are able to move.
Copyright: Sci. Adv. 2020; 6: eaaw 9975 (24 July 2020). Published under Creative Commons Attribution-NonCommercial license, which permits use, distribution, and reproduction in any medium, so long as the resultant use is not for commercial advantage and provided the original work is properly cited. To view a copy of this licence, visit https://creativecommons.org/licenses/by-nc/4.0/
Further Information:
Videos for download:
Ansprechpartner:
Dr. Gerrit Vliegenthart
Forschungszentrum Jülich
Theoretical Physics of Living Matter /Theory of Soft Matter and Biophysics (IBI-5/IAS-2)
Tel: +49 2461 61-6131
E-Mail: g.vliegenthart@fz-juelich.de
Pressekontakt:
Angela Wenzik, Science Journalist
Forschungszentrum Jülich
Tel: +49 2461 61-6048
E-Mail: a.wenzik@fz-juelich.de