Ion mediated crosslink driven mucous swelling kinetics

TL;DR

This study develops a multi-species ionic gel model to compare mucus swelling kinetics in healthy and Cystic Fibrosis conditions, highlighting the role of ion transport and polymer network properties.

Contribution

It introduces a novel multi-phasic, multi-species ionic gel model calibrated with experimental data to predict mucus rheology and swelling behavior in different health states.

Findings

Donnan potential dominates mucus swelling/deswelling transition.

Altered electrolyte movement affects Cystic Fibrosis mucus kinetics.

Polymer network defects influence mucus swelling properties.

Abstract

We present an experimentally guided, multi-phasic, multi-species ionic gel model to compare and make qualitative predictions on the rheology of mucus of healthy individuals (Wild Type) versus those infected with Cystic Fibrosis. The mixture theory consists of the mucus (polymer phase) and water (solvent phase) as well as several different ions: H+, Na+ and Ca++. The model is linearized to study the hydration of spherically symmetric mucus gels and calibrated against the experimental data of mucus diffusivities. Near equilibrium, the linearized form of the equation describing the radial size of the gel, reduces to the well-known expression used in the kinetic theory of swelling hydrogels. Numerical studies reveal that the Donnan potential is the dominating mechanism driving the mucus swelling/deswelling transition. However, the altered swelling kinetics of the Cystic Fibrosis infected mucus is not merely governed by the hydroelectric composition of the swelling media, but also due to the altered movement of electrolytes as well as due to the defective properties of the mucin polymer network.