Deformation of Hydrogel Inclusions by Tunable Motor-Driven Cytoskeletal Composites

The cytoskeleton is a dynamic and versatile network, composed of protein filaments such as semi-flexible actin and rigid microtubules, along with motor proteins, including kinesin and myosin. The forces generated throughout this composite network can range from highly heterogeneous to globally contractile or extensile depending on the concentrations and types of filaments, motors and crosslinkers. However, measuring these forces has proven challenging due to, in large part, the spatiotemporal heterogeneity of the force field. Here, we use synthetic hydrogel inclusions as reporters of motor-generated forces exerted by these composites by observing the extent to which the hydrogels flatten, shrink, or asymmetrically deform during motor activity. In turn, we characterize the impact of hydrogel inclusions on the structure and active dynamics of the composites, revealing increased resilience and connectivity. This unique ability to manipulate hydrogels through the controlled reconfiguration of cytoskeletal composites, and likewise improve the resilience of biopolymer networks using synthetic hydrogels, makes our bio-synthetic platform a promising route towards next-generation materials engineering and biomechanics.