Self-regulated non-reciprocal motions in single-material microstructures.

Living cilia stir, sweep and steer via swirling strokes of complex bending and twisting, paired with distinct reverse arcs. Efforts to mimic such dynamics synthetically rely on multimaterial designs but face limits to programming arbitrary motions or diverse behaviours in one structure. Here we show how diverse, complex, non-reciprocal, stroke-like trajectories emerge in a single-material system through self-regulation.

Liquid-induced topological transformations of cellular microstructures.

The fundamental topology of cellular structures-the location, number and connectivity of nodes and compartments-can profoundly affect their acoustic, electrical, chemical, mechanical and optical properties, as well as heat, fluid and particle transport. Approaches that harness swelling, electromagnetic actuation and mechanical instabilities in cellular materials have enabled a variety of interesting wall deformations and compartment shape alterations, but the resulting structures generally preserve the defining connectivity features of the initial topology. Achieving topological transformation presents a distinct challenge for existing strategies: it requires complex reorganization, repacking, and coordinated bending, stretching and folding, particularly around each node, where elastic resistance is highest owing to connectivity.