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Julia Davies

Professor

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PFG-NMR diffusometry: A tool for investigating the structure and dynamics of noncommercial purified pig gastric mucin in a wide range of concentrations

Author

  • Géraldine Lafitte
  • Olle Söderman
  • Krister Thuresson
  • Julia Davies

Summary, in English

For the first time, Pulsed Field Gradient-Nuclear Magnetic Resonance, a powerful noninvasive tool for studying the dynamics and structure of complex-gels, has been used to measure diffusion of probe molecules in aqueous solutions/gels of noncommercial purified pig gastric mucin (PGM), in a concentration range up to 5 wt%. Complementary data were obtained from rheology measurements. The combination of techniques revealed a strong pH dependency of the structure of the PGM samples while changes in concentration, ionic strength, and temperature appeared to induce less pronounced alterations. Viscosity was found to vary in a nonmonotonous way with pH, with the more viscous solutions found at intermediate pH. We propose that this finding is due to a reduced charge density at lower pH, which is expected to continuously increase the relative importance of hydrophobic associations. The results suggest a loose network of expanded fully charged PGM molecules woth considerable mobility at neutral pH (pH 7.4). At intermediate pH (pH 4), a three-dimensional expanded network is favored. At pH 1, the charge density is low and microphase seperation occurs since hydrophobic associations prevail. This leads to the formation of clusters concentrated in PGM molecules seperated by regions depleted in PGM. The results obtained increase our knowledge about the gastric mucosal layer, which in vivo contains mucin in the same concentration range as that of the samples investigated here. (c) 2007 Wiley Periodicals, Inc.

Department/s

  • Physical Chemistry
  • Diabetic Complications

Publishing year

2007

Language

English

Pages

165-175

Publication/Series

Biopolymers

Volume

86

Issue

2

Document type

Journal article

Publisher

John Wiley and Sons

Topic

  • Physical Chemistry

Keywords

  • rheology
  • PEG
  • structure and dynamics
  • mucin gel
  • PFG-NMR diffusometry

Status

Published

Research group

  • Diabetic Complications

ISBN/ISSN/Other

  • ISSN: 0006-3525