Autonomous chemo-mechanical oscillations in crosslinked filamentous actin gels

Mechanical oscillations play fundamental roles in cellular processes such as motility, signalling, and structural regulation; however, the mechanisms by which artificial cytoskeletal networks can be engineered to reproduce such autonomous oscillatory behaviours remain poorly understood. In this study, we demonstrate that a chemically polyethylene glycol-crosslinked filamentous actin hydrogel exhibits autonomous, long-lasting, and synchronised mechanical oscillations during self-organised polymerisation. These oscillations arise from chemo-mechanical responses coupled with the treadmilling polymerisation-depolymerisation equilibrium of filamentous actin. We propose that the rigid and highly hierarchical structure of the chemically crosslinked network plays an important role in the emergence of such autonomous mechanical oscillations. Our results reveal how hierarchical crosslinking and chemo-mechanical coupling drive sustained oscillations in active polymer networks, providing new insight into the fundamental mechanisms underlying autonomous dynamics in soft materials.