Topology and dynamics of active nematic vesicles

TLDR

Engineering synthetic materials that mimic living complexity is a fundamental challenge, and in active nematics defects move spontaneously rather than remaining static as in equilibrium systems. The study investigates spatiotemporal patterns that arise when an active nematic film of microtubules and motors is encapsulated in a deformable lipid vesicle. By combining activity, topological constraints, and vesicle deformability, the system generates diverse dynamical states. The experiments reveal a tunable periodic state oscillating between two defect configurations and shape‑changing vesicles with streaming filopodia‑like protrusions, demonstrating that topological constraints can steer non‑equilibrium dynamics to produce biomimetic materials.

Abstract

Engineering synthetic materials that mimic the remarkable complexity of living organisms is a fundamental challenge in science and technology. We study the spatiotemporal patterns that emerge when an active nematicfilm of microtubules and molecular motors is encapsulated within a shape-changing lipid vesicle. Unlike in equilibrium systems, where defects are largely static structures, in active nematics defects move spontaneously and can be described as self-propelled particles. The combination of activity, topological constraints and vesicle deformability produces a myriad of dynamical states. We highlight two dynamical modes: a tunable periodic state that oscillates between two defect configurations, and shape-changing vesicles with streaming filopodia-like protrusions. These results demonstrate how biomimetic materials can be obtained when topological constraints are used to control the non-equilibrium dynamics of active matter.