Enhanced microscopic dynamics in mucus gels under a mechanical load in the linear viscoelastic regime

• DOI: 10.1073/pnas.2103995118
• Publication Date: 2021-11-02T20:56:30Z
• Authors: Domenico Larobina; Angelo Pommella; Adrian-Marie Phil...; Med Yassine Nagazi; Luca Cipelletti
• Keywords: Penetration (warfare)

Mucus is a biological gel covering the surface of several tissues and insuring key functions, including as protective barrier against dehydration, pathogens penetration, or gastric acids. functioning requires finely tuned balance between solid-like fluid-like mechanical response, insured by reversible bonds mucins, glycoproteins that form gel. In living organisms, mucus subject to various kinds stresses, e.g. due osmosis, bacterial coughing peristalsis. However, our knowledge effects stress on still rudimentary mostly limited macroscopic rheological measurements, with no insight into relevant microscopic mechanisms. Here, we run tests simultaneously measurements dynamics pig mucus. Strikingly, find modest shear stress, within linear regime, dramatically enhances reorganization at level, signalled transient acceleration dynamics, up two orders magnitude. We rationalize these findings proposing simple yet general model for physical gels under strain validate its assumptions through numerical simulations spring networks. These results shed new light rearrangement scale, potential implications in phenomena ranging from clearance drug penetration.