Self-organized shape dynamics of active surfaces.
Proceedings of the National Academy of Sciences of the United States of America 116:1 (2019) 29-34
Abstract:
Mechanochemical processes in thin biological structures, such as the cellular cortex or epithelial sheets, play a key role during the morphogenesis of cells and tissues. In particular, they are responsible for the dynamical organization of active stresses that lead to flows and deformations of the material. Consequently, advective transport redistributes force-generating molecules and thereby contributes to a complex mechanochemical feedback loop. It has been shown in fixed geometries that this mechanism enables patterning, but the interplay of these processes with shape changes of the material remains to be explored. In this work, we study the fully self-organized shape dynamics using the theory of active fluids on deforming surfaces and develop a numerical approach to solve the corresponding force and torque balance equations. We describe the spontaneous generation of nontrivial surface shapes, shape oscillations, and directed surface flows that resemble peristaltic waves from self-organized, mechanochemical processes on the deforming surface. Our approach provides opportunities to explore the dynamics of self-organized active surfaces and can help to understand the role of shape as an integral element of the mechanochemical organization of morphogenetic processes.Active phase separation in mixtures of chemically-interacting particles
EUROPEAN BIOPHYSICS JOURNAL WITH BIOPHYSICS LETTERS 48 (2019) S207-S207
Active phase separation in mixtures of chemically-interacting particles
EUROPEAN BIOPHYSICS JOURNAL WITH BIOPHYSICS LETTERS 48 (2019) S66-S66
Chemotaxis mediated interactions can stabilize the hydrodynamic instabilities in active suspensions
Soft Matter, 2019, 15, 3248-3255
Abstract:
Ordered phases in active suspensions of polar swimmers are under long-wavelength hydrodynamic mediated instabilities. In this article, we show that chemical molecules dissolved in aqueous suspensions, as an unavoidable part of most wet active systems, can mediate long-range interactions and subsequently stabilize the polar phase. Chemoattractants in living suspensions and dissolved molecules in synthesized Janus suspensions are reminiscent of such chemical molecules. Communication between swimmers through the gradients of such chemicals is the foundation of this stabilization mechanism. To classify the stable states of such active systems, we investigate the detailed phase diagrams for two classes of systems with momentum conserving and non-conserving dynamics. Our linear stability analysis shows that the proposed stabilization mechanism can work for swimmers with different dynamical properties, e.g., pushers or pullers and with various static characteristics, e.g., spherical, oblate or prolate geometries.
DNA Systems Under Internal and External Forcing An Exploration Using Coarse-Grained Modelling Supervisor's Foreword
Chapter in DNA SYSTEMS UNDER INTERNAL AND EXTERNAL FORCING: AN EXPLORATION USING COARSE-GRAINED MODELLING, (2019) VII-+