CBE Seminar: Oleg Lavrentovich
Liquid crystals to control biological systems
Microscale biological systems such as swarms of swimming bacteria and cell tissues demonstrate fascinating out-of-equilibrium dynamics. This dynamics is difficult to control by factors other than transient gradients, such as gradients of nutrients; visual, acoustic and tactile communication channels that humans use to control large animals are not effective. To establish communication with microscale biological systems, we propose to use special classes of nontoxic liquid crystal with a long-range orientational order. The anisotropy axis of the liquid crystal can be designed as uniform or be pre-patterned into various structures . We describe how the patterned liquid crystals can be used to command dynamics of two systems, (i) swimming bacteria ,, and (ii) tissues formed by human dermal fibroblast (HDF) cells. Topological defects in liquid crystals are demonstrated to impact the biological microstructures most strongly, causing spatial variation of bacterial concentration and cell phenotype. 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, and sensing devices. The work is supported by NSF DMS-1729509, CMMI-1663394, and DOE DE-SC0019105 grants.
Unidirectional circulation of swimming bacteria around a topological defect in a liquid crystal; left: director field; center: swimming bacteria; right: velocity field.
C. H. Peng, Y. B. Guo, T. Turiv, M. Jiang, Q. H. Wei, and O. D. Lavrentovich, Patterning of Lyotropic Chromonic Liquid Crystals by Photoalignment with Photonic Metamasks, Advanced Materials 29, 1606112 (2017).
C. Peng, T. Turiv, Y. Guo, Q.-H. Wei, and O. D. Lavrentovich, Command of active matter by topological defects and patterns, Science 354, 882-885 (2016).
S. Zhou, O. Tovkach, D. Golovaty, A. Sokolov, I. S. Aranson, and O. D. Lavrentovich, Dynamic states of swimming bacteria in a nematic liquid crystal cell with homeotropic alignment, New Journal of Physics 19, 055006 (2017).
Oleg D. Lavrentovich is a Trustees Research Professor at Kent State University’s Advanced Materials and Liquid Crystal Institute, Department of Physics and Chemical Physics Interdisciplinary Program. He 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 at Kent State University as a Senior Research Fellow. He served as the director of the Institute in 2003-2011. He is a Fellow of the American Physical Society and International Society for Optical Engineering (SPIE). His current research focuses on active matter, interfacing soft matter with biological systems, electro-optics of liquid crystals, topological defects, liquid crystal elastomers, colloids and electrolytes. He is the editor of Liquid Crystals Reviews (Taylor & Francis) and associate editor of Soft Matter (Royal Society of Chemistry).