2021/12/21 by Guillaume Sarfati, Sarfati, Guillaume, Ananyo Maitra +9
Chemistry · Engineering · Physics and Astronomy · #Active matter #Advanced Materials and Mechanics #Bending #Biochemistry #Biological Physics (physics.bio-ph) #Biology #Biophysics #Buckling #Cell #Chemical physics #Chemistry #Composite material #Contraction (grammar) #Cytoskeleton #FOS: Physical sciences #Materials science #Mechanics #Micro and Nano Robotics #Orbital Angular Momentum in Optics #Physics #Protein filament #Soft Condensed Matter (cond-mat.soft) #Thermodynamics #Viscoelasticity #Work (physics) #cond-mat.soft #physics.bio-ph
paper · pdf · doi:10.48550/arxiv.2112.11361
published in arXiv (Cornell University) (Cornell University)
openalex publication_date 2021/12/21 · arxiv created 2022/01/11 · arxiv updated 2022/01/12 · openalex created_date 2022/05/05 · openalex updated_date 2026/07/28
Active gels made of cytoskeletal proteins are valuable materials with attractive non-equilibrium properties such as spatial self-organization and self-propulsion. At least four typical routes to spatial patterning have been reported to date in different types of cytoskeletal active gels: bending and buckling instabilities in extensile systems, and global and local contraction instabilities in contractile gels. Here we report the observation of these four instabilities in a single type of active gel and we show that they are controlled by two parameters: the concentrations of ATP and depletion agent. We demonstrate that as the ATP concentration decreases, the concentration of passive motors increases until the gel undergoes a gelation transition. At this point, buckling is selected against bending, while global contraction is favored over local ones. Our observations are coherent with a hydrodynamic model of a viscoelastic active gel where the filaments are crosslinked with a characteristic time that diverges as the ATP concentration decreases. Our work thus provides a unified view of spatial instabilities in cytoskeletal active matter.