Bond breaking dynamics in semiflexible networks under load

Area of Science:

• Biophysics
• Polymer Physics
• Soft Matter Physics

Background:

• Semiflexible polymer networks are crucial in biological systems.
• Understanding cross-linker dynamics is key to network mechanics.
• Transient cross-links introduce complex bond-breaking behaviors.

Purpose of the Study:

• To model the bond-breaking dynamics of transiently cross-linked semiflexible networks.
• To investigate the effects of quenched disorder and stochastic bond-breaking on dissociation dynamics.
• To compare theoretical predictions with experimental observations in microtubule networks.

Main Methods:

• Utilized a single filament model simulating peeling from cross-linkers.
• Incorporated quenched disorder in linker placement.
• Applied Bell model unbinding kinetics for stochastic bond-breaking.
• Analyzed force decay and sequential bond rupture events.
• Compared model predictions to experimental trajectories of beads in microtubule networks.

Main Results:

• Observed exponential decay of bond forces away from the loading point.
• Demonstrated sequential bond breaking down the linker array via stochastic ripping events.
• Identified correlations between predicted linker rupture events and experimental bead jumps.
• Quantified the statistics of filament-cross-linker dissociation events.

Conclusions:

• The single filament model accurately captures bond-breaking dynamics in cross-linked networks.
• Quenched disorder and stochasticity significantly influence dissociation pathways.
• Experimental bead movements in microtubule networks are consistent with theoretical linker rupture events.