Microrheology of gel-forming airway mucins isolated from porcine trachea†

Abstract

Mucus produced in the lungs has important protective barrier functions that strongly depend on its biomolecular composition, biopolymer network architecture, and viscoelastic properties. However, to date, there has yet to be a readily available source of reconstituted, gel-forming mucins from the lungs to model and study its biophysical properties. To address this, we established an in-house procedure to extract airway mucins from pig trachea with minimal DNA contamination consisting of ∼70% by weight protein. Particle tracking microrheology was used to evaluate the biophysical properties of porcine trachea mucins for comparison to other reconstituted mucin and native mucus gels. At an ionic strength and pH reflective of conditions in the lungs, we found that porcine tracheal mucins formed a tighter mesh network and possessed a significantly greater microviscosity compared to mucins extracted from the porcine small intestine. In comparison to mucus harvested from human airway tissue cultures, we found that porcine tracheal mucins also possessed a greater microviscosity, suggesting that these mucins can form into a gel at physiological total solid concentrations.