title: A combined small-angle X-ray and neutron scattering study of the structure of purified soluble gastrointestinal mucins.
abstract: The structures of purified soluble porcine gastric (Muc5ac) and duodenal (Muc2) mucin solutions at neutral and acidic pH were examined using small-angle X-ray scattering and small-angle neutron scattering experiments. We provide evidence for the morphology of the network above the semidilute overlap concentration and above the entanglement concentration. Furthermore, we investigated the gelation of both types of mucin solutions in response to a reduction in pH, where we observed the formation of large-scale heterogeneities within the polymer solutions, typical of microphase-separated gels. The concentration dependence of the inhomogeneity length scale (Ξ) and the amplitude of the excess scattering intensity [I(ex) (0)] are consistent with previously studied gelled synthetic polymeric systems. The persistence lengths of the chains were found to be similar for both Muc5ac and Muc2 from Kratky plots of the neutron data (8 ± 2 nm).
authors.affiliation: Biological Physics, Department of Physics and Astronomy, University of Manchester, Manchester, M60 1QD, UK; Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK.
authors.forename: Pantelis
authors.initials: P
authors.lastname: Georgiades
authors.forename: Emanuela
authors.initials: E
authors.lastname: di Cola
authors.forename: Richard K
authors.initials: RK
authors.lastname: Heenan
authors.forename: Paul D A
authors.initials: PD
authors.lastname: Pudney
authors.forename: David J
authors.initials: DJ
authors.lastname: Thornton
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Waigh
mesh_terms: D000818:Animals; D041981:Gastrointestinal Tract / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D055271:Mucin 5AC / Q000737:chemistry*; D055262:Mucin-2 / Q000737:chemistry*; D033363:Neutron Diffraction; D053838:Scattering, Small Angle; D012995:Solubility; D034421:Sus scrofa; D014961:X-Ray Diffraction
chemical_list: D055271:Mucin 5AC; D055262:Mucin-2
keywords: DLS; SANS; SAXS; gastric; intestinal; mucin