| Cohesion in biological systems is often provided by clusters of biomolecular bonds which stochastically open and close. Cooperativity arises due to several mechanisms, most prominently due to load sharing. We introduce simple stochastic models for different biological systems of interest. For contractile tissue cells adhering to flat substrates through focal adhesions, we use master equations to investigate the stability of layered structures under the action of a disrupting force. For cell adhesion in hydrodynamic flow, we use a Langevin equation approach to show how adhesion converts slipping into rolling. Motivated by retrograde flow of the actin cytoskeleton over focal adhesions, we demonstrate that stochastic bond dynamics between moving interfaces result in non-linear friction laws. |
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