Detailed Balance Broken by Catch Bond Kinetics Enables Mechanical‐Adaptation in Active Materials. (16th December 2020)

• Record Type: Journal Article
• Authors: Tabatabai, Alan Pasha; Seara, Daniel S.; Tibbs, Joseph; Yadav, Vikrant; Linsmeier, Ian; Murrell, Michael P.
• Is Part Of: Advanced functional materials. Volume 31:Number 10(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-12-16
• Subjects: catch bonds -- detailed balance -- active matter; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.202006745
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: Unlike nearly all engineered materials which contain bonds that weaken under load, biological materials contain "catch" bonds which are reinforced under load. Consequently, materials, such as the cell cytoskeleton, can adapt their mechanical properties in response to their state of internal, non‐equilibrium (active) stress. However, how large‐scale material properties vary with the distance from equilibrium is unknown, as are the relative roles of active stress and binding kinetics in establishing this distance. Through course‐grained molecular dynamics simulations, the effect of breaking of detailed balance by catch bonds on the accumulation and dissipation of energy within a model of the actomyosin cytoskeleton is explored. It is found that the extent to which detailed balance is broken uniquely determines a large‐scale fluid‐solid transition with characteristic time‐reversal symmetries. The transition depends critically on the strength of the catch bond, suggesting that active stress is necessary but insufficient to mount an adaptive mechanical response. Abstract : While most engineered materials contain passive bonds that weaken under load, biological materials contain bonds that not only generate forces, but also increase their bound lifetime with applied force. These active "catch bonds" break detailed balance and induce a mechanical phase transition characterized by different symmetries under time‐reversal in simulations of an active biomaterial, the cell cytoskeleton.