Essentially all biology is active and dynamic. Biological entities autonomously sense, compute, and respond using energy-coupled ratchets that can produce force and do work. The cytoskeleton, along with its associated proteins and motors, is a canonical example of biological active matter, which is responsible for cargo transport, cell motility, division, and morphology. Prior work on cytoskeletal active matter systems showed either extensile or contractile dynamics. Here, we demonstrate a cytoskeletal system that can control the direction of the network dynamics to be either extensile, contractile, or static depending on the concentration of filaments or transient crosslinkers through systematic variation of the crosslinker or microtubule concentrations. Based off these new observations and our previously published results, we created a simple one-dimensional model of the interaction of filaments within a bundle. Despite its simplicity, our model recapitulates the observed activities of our experimental system, implying that the dynamics of our finite networks of bundles are driven by the local filament-filament interactions within the bundle. Finally, we show that contractile phases can result in autonomously motile networks that resemble cells. Our experiments and model allow us to gain a deeper understanding of cytoskeletal dynamics and provide a stepping stone for designing active, autonomous systems that could potentially dynamically switch states.
We would like to thank Dr. Peker Milas and Dr. Art Evans for constructive conversation about particle tracking, active matter theory, and models. K.S. was funded by NSF Inspire grant 1344203 to J.L.R, NIH RO1-GM109909 to J.L.R. and The Mathers Foundation. V.Y. was funded by NSF Inspire to J.L.R., MURI 67455-CH-MUR, and Mathers Foundation. C.S. is funded by NSF EFRI ODISSEI 1240441 and Keck Foundation. J.L.R. was funded by NSF INSPIRE, Mathers Foundation, NIH, and MURI.
|Original language||English (US)|
|State||Published - Mar 25 2017|
ASJC Scopus subject areas