Active systems change structure similarly to how liquid crystals grow
Some groups of bacteria or cell tissues create active systems that show a complex behaviour and change from ordered to disordered states spontaneously. This behaviour pattern is similar to the one presented by active nematics. Now, a team of researchers of the UB has published an article in Nature Physics which studies the transition from one structure to the other in these systems and which determines this transition can be mathematically described similarly to the growth of liquid crystals when they freeze.
Some groups of bacteria or cell tissues create active systems that show a complex behaviour and change from ordered to disordered states spontaneously. This behaviour pattern is similar to the one presented by active nematics. Now, a team of researchers of the UB has published an article in Nature Physics which studies the transition from one structure to the other in these systems and which determines this transition can be mathematically described similarly to the growth of liquid crystals when they freeze.
In this study, a team of researchers from the Institute of Nanoscience and Nanotechnology (IN2UB) and the Institute of Complex Systems (UBICS), both from the UB, have used a protein extract from the cytoskeleton, responsible for several biological functions such as the regulation of cell division, to prepare an in vitro active nematic -a type of system featured by long-shaped self-managed units- to study the dynamics of the process undergone by the well-organized system to a disordered configuration, known as active turbulence.
“Using a micro suction mechanism, we prepared an initial condition under which the filamentous proteins are aligned, so we could see the way that spontaneously leads these to an unorganized situation”, says Berta Martínez Prat, researcher at IN2UB and the Department of Materials Science and Physical Chemistry -and first author of the study.
The results show the transition towards the active turbulence follows a well-organized order, with continuous foldings, similar to the order in how liquid crystals freeze. These results open a new view to understand complex dynamic processes in active systems, and eventually, to find new ways to control them.
As stated in the article published in the section News and Views of the same journal, “this behaviour had been previously predicted and had been seen in other systems such as bacteria”.
Article reference:
Martínez Prat, B.; Ignés Mullol, J.; Casademunt, J., and Sagués, F. "Selection mechanism at the onset of active turbulence". Nature Physics, 2019. Doi: 10.1038/s41567-018-0411-6