1 / 2017-05-16 01:49:59

Surface Pattern Formation in Biological Liquid Crystal Membranes

14391,14392,14393,14394,14395

Liquid crystalline phases found in many biological materials, such as actin, DNA, cellulose, and collagen can be responsible for the deformation of cell membranes. In this study, the cell membrane deformation is investigated though the coupling between the liquid crystal anisotropy and the bending elasticity of the membrane. The generalized shape equation for anisotropic interfaces using the Cahn-Hoffman capillarity vector, the Rapini-Papoular anchoring energy, and the Helfrich elastic energy is applied to understand the deformation of closed biological liquid crystal membrane. We present a general morphological phase diagram of the membrane surface patterns, in which we classify two characteristic regimes of membrane shapes based on whether the liquid crystal anisotropy or bending elasticity is dominant. Our results indicate that, depending on the bending elasticity of the cell membrane, the liquid crystal might be able to deform the cell resulting in anisotropic asymmetric shapes. As liquid crystal anisotropy dominates the bending elasticity, spindle-like or tactoid shapes which are extensively observed in experiments can be formed. All these findings provide a foundation to understand the topologies in living soft matters. Furthermore, the coupling between the order and the curvature of the membrane enable to open new opportunities to design novel functional soft materials.