From interfacial tubulation in Alcanivorax borkumensis biofilms to folding of membranes with nematic order.
Carles Blanch Mercader ( Physico-Chimie Curie )
Assemblies of anisotropic cells can exhibit long-range orientational order and topological defects, which often influence processes of shape formation. In the first part of this talk, I will introduce conditions for a morphological transition between a spherical and a dendritic phase in Alcanivorax borkumensis biofilm-covered oil microdroplets. Experimental observations demonstrate preferential interfacial tubulation at topological defects; bacteria assemblies on these tubes exhibit long-range nematic order. The second part of this talk focuses on the role of order-curvature couplings on equilibrium states of a membrane with nematic order that are generated by an integer topological defect. For varying elastic parameters and boundary anchoring conditions, the instability of a flat disc towards an out-of-plane deformed surface will be discussed. Finally, I will argue how these results can be relevant for biological systems and show how bacteria biofilms can utilize topological defects to facilitate membrane deformation and enhance oil access.
The first part is a joint work with M. Prasad, N. Obana, S.-Z. Lin, K. Sakai, J. Prost, N. Nomura, J.-F. Rupprecht, J. Fattaccioli, and A.S. Utada. The second part is a joint work with C. Thibault, Q. Chaboche, and D.J.G. Pearce.