Myosin-driven advection and actin reorganization control the geometry of confined actomyosin gel

TL;DR

This study demonstrates how geometrical confinement influences actomyosin network organization through myosin-driven flow, enabling control over gel shape and size for designing responsive biomaterials.

Contribution

It introduces a microfabricated system combining experiments and simulations to show how boundary shape directs actomyosin organization and dynamics.

Findings

Microwell shape directs actomyosin organization.

Myosin-driven actin flow transfers boundary asymmetry.

Tuning contractility controls gel size and shape.

Abstract

Harnessing nanoscale motor proteins to actively control material shape is a promising strategy in nanotechnology and material science. One notable system is the actomyosin network, composed of actin filaments and myosin motor proteins, providing a natural platform for constructing contractile, shape-adaptive materials. While the role of actomyosin in shaping cells has been extensively studied, the reverse question - how boundary shape affects the actomyosin system - remains poorly understood. Here, we present a microfabricated system that reveals how geometrical confinement directs the organization of actomyosin networks within microwells. By combining experimental and numerical analysis, we show that the asymmetric shape of the microwells is transferred to contracted actomyosin gels via myosin-driven actin flow. Furthermore, tuning myosin contractility and actin polymerization rate allows control over the size and shape of actomyosin gels. Our findings provide a bottom-up framework for integrating molecular motors and cytoskeletons into confined architectures to create responsive biomaterials.