Living Active Matter—Understanding the Self-Organisation of Bacteria in Liquid Environments for a Novel Class of Biomaterials

Active matter is commonly defined as soft systems with built-in dispersed and local conversion of energy into forces and motions. Usually in soft matter physics, it refers to systems composed of individual units (or particles) that consume energy to produce motion or mechanical work. Here we propose to use <i>Flavobacterium IR1</i>, a gram-negative bacterium characterized by its rod-shaped cells and gliding motility, as a new building block to study non-equilibrium dynamics of colloidal liquid crystals. In this work, we observed that the increase of bacteria packing fraction triggers a liquid crystal-like phase transition from isotropic to nematic, then hexatic columnar phase. Microscopic changes to liquid crystal nanostructures are monitored with a variety of optical and electron microscopy techniques.