Biological Physics of Living Active Nematics

ended

The growth of a bacterial colony is a fascinating example of a biological process that can be interpreted in physical terms as the interaction of a collection of elementary units - the cells - with the surrounding environment and within themselves, whereby energy is harnessed and dissipated, thus determining inherent non-equilibrium conditions. Although bacterial cells are one of the simplest forms of life, scientists have so far found difficult to build theoretical models of bacterial growth and morphology as well as to perform controlled experiments of the real systems occurring in nature. These difficulties arise from the naturally occurring conditions that are characterized by a large degree of complexity in both morphological and chemical terms. The aim of this project is to investigate through novel experimental approaches the biological physics which is at the foundation of the formation of 2D bacterial microcolony and its successive development to a 3D structure. To this purpose, several experimental techniques, from traction force microscopy, through laser ablation and soft lithography will be exploited. Furthermore, experimental results obtained from these studies will be of great relevance for the validation of numerical and theoretical models of bacterial colony morphogenesis and antibiotics exposure. The planned research activities will be carried out in one of the top research laboratory in Europe for active matter and within the wider context of École Normale Supérieure, a world renowned academic institution in the fields of statistical mechanics, soft matter and optics. This project aims thus at providing fundamental insights into the development of early stages of bacterial community formation, trying to establish what physical parameters related to the cells, the environment and their interactions determine the transitions from a 2D to a 3D structure, and lastly to gain control over these parameters.