Potential use of mucins as biomaterial coatings. II. Mucin coatings affect the conformation and neutrophil-activating properties of adsorbed host proteins-Toward a mucosal mimic

In continuation of our recent fractionation and characterization study on mucins of bovine salivary (BSM), porcine gastric (PGM), and human salivary (MG1) origin, this study evaluates the effect of mucin precoating on the conformation and neutrophil-activating properties of host proteins adsorbed to a polyethylene terephthalate-based model biomaterial. Microscopy combined with assays for the neutrophil releases of reactive oxygen species and human neutrophil lipocalin showed that mucin precoating greatly reduced the strong immune-response normally induced by adsorbed immunoglobulin G (IgG) and secretory immunoglobulin A (sIgA), respectively. A similar finding was made for the proinflammatory fibrinogen. Although the total uptakes of these proteins depended on the mucin surface concentration, a detailed composite analysis suggested the fraction Of surface-exposed protein to be a stronger determinant of coating performance. The unexpectedly low neutrophil activation showed by composites containing near-monolayer concentrations of exposed IgG and sIgA, respectively, suggested that these act synergistically with mucin on the surface. In support of this hypothesis, quartz crystal microbalance with dissipation monitoring measurements revealed that a preadsorbed BSM layer stabilizes IgG through complexation on a polymeric model surface. Our findings link well to the complex in vivo situation and suggest that functional mucosal mimics can be created in situ for improved biomaterials performance. (C) 2008 Wiley Periodicals, Inc. J Biomed Mater Res 91A: 773-785, 2009