2007/06/04 by Yuxia Luan, Oliver Lieleg, Bernd Wagner +1 · 1 citation
Biochemistry, Genetics and Molecular Biology · Chemistry · Medicine · Physics and Astronomy · #Actin #Blood properties and coagulation #Cellular Mechanics and Interactions #Chemical physics #Chemistry #Composite material #Computer science #Elasticity (physics) #Force Microscopy Techniques and Applications #Linker #Materials science #Microrheology #Molecule #Network structure #Polymer #Viscoelasticity #cond-mat.soft
paper · pdf · doi:10.1529/biophysj.107.112417
14 pages, 5 figures
arxiv created 2007/06/04 · openalex publication_date 2007/09/14 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Cells make use of semi-flexible biopolymers such as actin or intermediate filaments to control their local viscoelastic response by dynamically adjusting the concentration and type of cross-linker molecules. The microstructure of the resulting networks mainly determines their mechanical properties. It remains an important challenge to relate structural transitions to both the molecular properties of the cross-linking molecules and the mechanical response of the network. This can be achieved best by well-defined in vitro model systems in combination with microscopic techniques. Here, we show that with increasing concentrations of the cross-linker HMM (heavy meromyosin) a transition in the mechanical network response occurs. At low cross-linker densities the network elasticity is dominated by the entanglement length of the polymer, while at high HMM densities the cross-linker distance determines the elastic behavior. Using microrheology the formation of heterogeneous networks is observed at low cross-linker concentrations. Micro- and macrorheology both report the same transition to a homogeneous cross-linked phase. This transition is set by a constant average cross-linker distance. Thus, the micro- and macromechanical properties of isotropically cross-linked in vitro actin networks are determined by only one intrinsic network parameter.