Worm Blobs as Entangled Living Polymers: From Topological Active Matter to Flexible Soft Robot Collectives

Abstract: Recently, long and slender living worms have garnered significant interest because of their impressive ability to exhibit diverse emergent behaviors in highly entangled physical and topological conditions. These worms can form an active viscoelastic, three-dimensional soft entity known as the 'blob', which can behave like a solid, flow like a liquid, and even respond to external stimuli such as light to locomote or change shape. To understand the behavior of the blob, it is crucial to consider the high degree of conformational entanglement that individual units can achieve because of their high aspect ratio and tunable activity. This topologically active collective necessitates reevaluating established soft matter concepts in polymer physics to advance the development of active polymer-like materials. Our understanding of the complex emergent dynamics of the worm blob promises to catalyze further research into the behavior of entangled active polymers and guide the design of synthetic topological active matter and bioinspired tangling soft robot collectives.