Liquid crystal patterns to command living matter

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, and sometimes even enable, dynamics in systems of (i) swimming bacteria; (ii) living tissues of human dermal fibroblast (HDF) cells. Topological defects 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.