Command of micro-organisms by liquid crystals

Data de Início: 
quinta-feira, 19 Agosto, 2021 - 16:00
Palestrante: 
Prof. Oleg Lavrentovich - Kent State University, Kent, Ohio, USA
Local: 
Videoconferência

 

Acesso:

► Via Zoom (para participação ao vivo): https://zoom.us/j/99040780268

► Ou pelo You Tube - cilque na tela acima

Resumo: Active systems such as swarms of swimming bacteria and cell tissues demonstrate fascinating dynamics that can potentially be used in microscale applications. Control of this dynamics in isotropic media such as water is difficult.  We describe an approach in which instead of an isotropic medium, the dynamics of micro-organisms is guided by a liquid crystal.  An example with a droplet of an active bacterial suspension shows an immediate benefit of such a replacement: when placed in an isotropic fluid, the droplet experiences random Brownian motion, but once the medium becomes a nematic liquid crystal, the droplet acquires an ability to swim unidirectionally along a prescribed trajectory [1]. Other examples of liquid crystal control over the dynamics of microscopic objects include dynamic swarms of swimming bacteria [2-4]and living tissues [5]. Director gradients and topological defects impact the biological microstructures most strongly, causing spatial variation of bacterial concentration and cell phenotype and shaping irreversible active flows.  The physical mechanisms are shaped by the nontrivial effect of the orientational order of a liquid crystal on the interactions of dynamic active units.  The control of active matter by patterned liquid crystals might result in new approaches to harness the energy of collective motion for micro-robotic, biomechanical, biomedical, and sensing applications. The work is supported by NSF DMR-1905053 and DOE DE-SC0019105 grants.

Sobre o palestrante:  Oleg D. Lavrentovich received his Ph.D. (1984) and Doctor of Science (1990) degrees in Physics and Mathematics from the Ukrainian Academy of Sciences. In 1992 he joined the Liquid Crystal Institute as a Senior Research Fellow. He served as the director of institute in 2003-2011. Fellow of SPIE and American Physical Society.  Lavrentovich held visiting appointments at the University P. et M. Curie, University Denis Diderot in France and other universities. He is the editor of Liquid Crystals Reviews (Taylor & Francis), associate editor of Soft Matter, member of the Editorial Boards of Liquid Crystals, Condensed Matter Physics, Ukrainian Journal of Physics and Advisor of the Kent State University SPIE Student Chapter.

Palavras-chavesswimming bacteria, liquid crystals

 

Desenvolvido por IFUSP