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How cells with diverse morphologies and cytoskeletal architectures modulate their mechanical behaviors to drive robust collective motion within tissues is poorly understood. During wound repair within epithelial monolayers in vitro, cells…
Across all scales of the physical world, dynamical systems can often be usefully represented as abstract networks that encode the system's units and inter-unit interactions. Understanding how physical rules shape the topological structure…
Molecular-motor generated active stresses drive the cytoskeleton away from equilibrium, endowing it with tunable mechanical properties that are essential for diverse functions such as cell division and motility[1-5]. Designing analogous…
Crosslinks and molecular motors play an important role in the organization of cytoskeletal filament networks. Here we incorporate the effect of crosslinks into our model of polar motor-filament organization [Phys. Rev. E {\bf 71}, 050901…
We present a theory for the elasticity of cross-linked stiff polymer networks. Stiff polymers, unlike their flexible counterparts, are highly anisotropic elastic objects. Similar to mechanical beams stiff polymers easily deform in bending,…
The internal dynamics of active gels, both in artificial (in-vitro) model systems and inside the cytoskeleton of living cells, has been extensively studied by experiments of recent years. These dynamics are probed using tracer particles…
Many cell membrane proteins that bind to actin form dynamic clusters driven by contractile flows generated by the actomyosin machinery at the cell cortex. Recent evidence suggests that a necessary condition for the generation of these…
Propulsion by growing actin networks is a universal mechanism used in many different biological systems. Although the core molecular machinery for actin network growth is well preserved in most cases, the geometry of the propelled obstacle…
We investigate the growth of a branched actin network under load. Using a combination of simulations and theory, we show that the network adapts to the load and exhibits two regimes: a finite velocity at low stress, followed by a power-law…
Cell spreading requires a major reorganisation of the actin cytoskeleton, from a cortical structure to a lamellipodium where filaments are mostly parallel to the substrate. We propose a model inspired by the physics of nematic liquid…
Active materials are capable of converting free energy into directional motion, giving rise to striking dynamical phenomena. Developing a general understanding of their structure in relation to the underlying non-equilibrium physics would…
Many biological processes involve the action of molecular motors that interact with the cell cytoskeleton. Some processes, such as the transport of cargoes is achieved mainly by the action of individual motors. Other, such as cell motility…
Filamentous actin, a species of dynamic protein polymers, is one of the main components of the cytoskeleton of eukaryotic cells. We formulate a class of models that predict the possibility of bistable steady states in populations of dynamic…
Collagen is the main structural and load-bearing element of various connective tissues, where it forms the extracellular matrix that supports cells. It has long been known that collagenous tissues exhibit a highly nonlinear stress-strain…
Mechanically induced unfolding of passive crosslinkers is a fundamental biological phenomenon encountered across the scales from individual macro-molecules to cytoskeletal actin networks. In this paper we study a conceptual model of…
We provide conditions guaranteeing that certain classes of robust heteroclinic networks are asymptotically stable. We study the asymptotic stability of ac-networks --- robust heteroclinic networks that exist in smooth ${\mathbb…
We represent a filamentous actin molecule as a graph of finite-state machines (F-actin automaton). Each node in the graph takes three states --- resting, excited, refractory. All nodes update their states simultaneously and by the same…
Cytoskeletons are self-organized networks based on polymerized proteins: actin, tubulin, and driven by motor proteins, such as myosin, kinesin and dynein. Their positive Darwinian evolution enables them to approach optimized functionality…
Cytoskeletal networks are the main actuators of cellular mechanics, and a foundational example for active matter physics. In cytoskeletal networks, motion is generated on small scales by filaments that push and pull on each other via…
F-actin bundles constitute principal components of a multitude of cytoskeletal processes including stereocilia, filopodia, microvilli, neurosensory bristles, cytoskeletal stress fibers, and the sperm acrosome. The bending, buckling, and…