Comprehensive characterization of the viscoelastic properties of Bovine Submaxillary Mucin (BSM) hydrogels and the effect of additives

This study presents a comprehensive characterization of the viscoelastic and structural properties of Bovine Submaxillary Mucin (BSM), which is widely used as a commercial source to conduct mucus-related research. We conducted concentration studies of BSM and examined the effects of various additives - NaCl, CaCl2, lysozyme, and DNA - on its rheological behavior. A notable connection between BSM concentration and viscoelastic properties was observed, particularly under varying ionic conditions. The rheological spectra could be well-described by a fractional Kelvin-Voigt Model with a minimum of model parameters. A detailed proteomics analysis provided insight into the molecular interactions within BSM, showing MUC19 as main component. Cryo-scanning electron microscopy allowed to visualize the network structure in relation to the rheological data. By elucidating the complex interplay between mucin concentration, environmental conditions, and viscoelastic properties, this research significantly contributes to the field of mucus research and lays an important basis for its further advancement.