Force and Power Generation by Contractile Actomyosin Gels

Contractile actomyosin gels are a central source of active cellular force generation. However, the principles underlying the active generation of forces and mechanical power in such gels remain elusive. Specifically, it is unclear how the short time-scale motor dynamics controls the large-scale dynamics and thermodynamics of active stress generation. Here, we introduce a novel experimental system which couples reconstituted actomyosin networks to 3D-printed elastic scaffolds, enabling a dynamic quantification of the generated forces. We observe that the contraction is characterized by a dramatic acceleration, which we show using a model to be due to the load-dependent kinetics of the myosin motors. Thus, we find how the microscopic properties of molecular motors control the macroscopic contraction dynamics. Our model provides insights on how interplay between network mechanics and motor dynamics impacts the large-scale dynamics and thermodynamics of contractile actomyosin gels.