Berlin 2024 – scientific programme
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DY: Fachverband Dynamik und Statistische Physik
DY 54: Active Matter V (joint session BP/DY)
DY 54.2: Talk
Friday, March 22, 2024, 09:45–10:00, H 1028
Pulsatile Control of Actomyosin Contraction — •James Clarke and José Alvarado — Department of Physics, The University of Texas at Austin, Austin, Texas, USA
Cells are always under control and tightly control their mechanics. The actomyosin cytoskeleton is one important cellular structure which receives control signals and turns that into contraction. Existing research has investigated the mechanical properties of actomyosin materials. However, these are usually in terms of responses to external stresses, which may be absent in living systems. Here we instead measure response to biochemical control signals. We apply a control-theoretical framework and investigate quasistatic actomyosin contractility in response to external pulsatile signals of UV light that release ATP molecules from light-sensitive NPE-cages. Across all experimental conditions, we report statistically indistinguishable maximum strains achieved by the gel. We find that the coupling from energy input to contractile strain is weakly nonlinear, with a s−2 dependence in Laplace space. Our novel characterization is not only an essential first step in a better understanding of how cells control cytoskeletal contractions via internal control signals. It is also an essential first step towards using biomimetic actomyosin active gels for microrobotic applications.
Keywords: Actomyosin; Control Theory; Biomimetic; Biomechanics; Biopolymers