生きたもつれ物質の超高速可逆的自己組織化 Ultrafast reversible self-assembly of living tangled matter
Vishal P. Patil,Harry Tuazon,Emily Kaufman,Tuhin Chakrabortty,David Qin ,Jörn Dunkel and M. Saad Bhamla
Science Published:27 Apr 2023
Anyone who has ever packed away rope without coiling it properly knows how easily it gets tangled and how difficult it can be to untangle. By contrast, California blackworms will migrate into a tangled ball over the course of minutes to regulate temperature or moisture but then disentangle and scatter within milliseconds upon sensing danger. Patil et al. combined ultrasound studies of worms with theory to develop a model of how the movement of individual worms (or filaments) affects the collective dynamics (see the Perspective by Panagiotou). In particular, they found that alternating helical waves enabled both tangle formation and ultrafast untangling. —Marc S. Lavine
Tangled active filaments are ubiquitous in nature, from chromosomal DNA and cilia carpets to root networks and worm collectives. How activity and elasticity facilitate collective topological transformations in living tangled matter is not well understood. We studied California blackworms (Lumbriculus variegatus), which slowly form tangles in minutes but can untangle in milliseconds. Combining ultrasound imaging, theoretical analysis, and simulations, we developed and validated a mechanistic model that explains how the kinematics of individual active filaments determines their emergent collective topological dynamics. The model reveals that resonantly alternating helical waves enable both tangle formation and ultrafast untangling. By identifying generic dynamical principles of topological self-transformations, our results can provide guidance for designing classes of topologically tunable active materials.