Spontaneous buckling of poroelastic actomyosin sheets
Anne Bernheim of Ben Gurion University
Planar actively contractile materials can self-organize into various patterns. While the in-plane dynamics due to active stresses was extensively studied, the role of such contractility in producing out-of-plane deformations has not been explored. Here, we show that the contraction dynamics of myosin motors leads to buckling of initially homogenous, thin, poroelastic actin sheets. Motor-induced contraction depends on system size due to the long-range nature of elastic forces. Contraction starts at the system boundaries, proceeds into the bulk, eventually leading to spontaneous buckling of the entire sheet. This instability is intimately linked to the spontaneous emergence of gradients in the gel density during contraction. Our system offers a well-controlled way to study mechanically induced, spontaneous shape transitions in active matter.