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Effect of pH on the association behavior in aqueous solutions of pig gastric mucin

Maleki, Atoosa; Lafitte, Géraldine LU ; Kjoniksen, Anna-Lena; Thuresson, Krister LU and Nyström, Bo (2008) In Carbohydrate Research 343(2). p.328-340
Abstract
In this study, dynamic light scattering (DLS), turbidity, and rheo-small angle light scattering (rheo-SALS) methods have been utilized to examine the impact of pH (1 <= pH <= 7) on aqueous solutions of noncommercial purified pig gastric mucin. The asymmetric flow field-flow fractionation (AFFFF) measurements established that the mucin sample has a high molecular weight and is polydisperse. DLS measurements on dilute solutions of mucin disclosed large interchain aggregates at pH 2, where the polymer has a low charge density or is uncharged. At lower or higher values of pH, mucin is charged and the tendency of forming interpolymer complexes is affected. In the semidilute concentration regime, pronounced junction zones (`lumps' of... (More)
In this study, dynamic light scattering (DLS), turbidity, and rheo-small angle light scattering (rheo-SALS) methods have been utilized to examine the impact of pH (1 <= pH <= 7) on aqueous solutions of noncommercial purified pig gastric mucin. The asymmetric flow field-flow fractionation (AFFFF) measurements established that the mucin sample has a high molecular weight and is polydisperse. DLS measurements on dilute solutions of mucin disclosed large interchain aggregates at pH 2, where the polymer has a low charge density or is uncharged. At lower or higher values of pH, mucin is charged and the tendency of forming interpolymer complexes is affected. In the semidilute concentration regime, pronounced junction zones (`lumps' of polymer) are evolved and a heterogeneous connected network is formed at pH 2, whereas the association structures are disintegrated (smaller `lumps') at lower or higher pH values due to electrostatic repulsive interactions, and a more homogeneous network is evolved. The DLS and viscosity results at pH 1 indicate the development of a fragmented network, composed of contracted chains that are decorated by some positive charges. The effect of shear flow on the structure of semidilute solutions of mucin was investigated with the aid of rheo-SALS methods. The scattered intensity revealed a strong upturn at low values of the wave vector (q) for mucin solutions at pH 2 and pH 4, which suggests the evolution of large association domains. At these pH values, a flow-induced anisotropy in the 2D SALS patterns in the form of elliptical shapes was observed at high shear rates. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
light scattering, rheo-small angle, purified pig gastric mucin, dynamic light scattering, effect of pH, associations
in
Carbohydrate Research
volume
343
issue
2
pages
328 - 340
publisher
Elsevier
external identifiers
  • wos:000253026500018
  • scopus:38049078712
ISSN
1873-426X
DOI
10.1016/j.carres.2007.10.005
language
English
LU publication?
yes
id
ed86459e-bd82-407d-8679-a18996cd6ac6 (old id 1198796)
date added to LUP
2008-09-10 17:04:54
date last changed
2017-09-03 03:46:18
@article{ed86459e-bd82-407d-8679-a18996cd6ac6,
  abstract     = {In this study, dynamic light scattering (DLS), turbidity, and rheo-small angle light scattering (rheo-SALS) methods have been utilized to examine the impact of pH (1 &lt;= pH &lt;= 7) on aqueous solutions of noncommercial purified pig gastric mucin. The asymmetric flow field-flow fractionation (AFFFF) measurements established that the mucin sample has a high molecular weight and is polydisperse. DLS measurements on dilute solutions of mucin disclosed large interchain aggregates at pH 2, where the polymer has a low charge density or is uncharged. At lower or higher values of pH, mucin is charged and the tendency of forming interpolymer complexes is affected. In the semidilute concentration regime, pronounced junction zones (`lumps' of polymer) are evolved and a heterogeneous connected network is formed at pH 2, whereas the association structures are disintegrated (smaller `lumps') at lower or higher pH values due to electrostatic repulsive interactions, and a more homogeneous network is evolved. The DLS and viscosity results at pH 1 indicate the development of a fragmented network, composed of contracted chains that are decorated by some positive charges. The effect of shear flow on the structure of semidilute solutions of mucin was investigated with the aid of rheo-SALS methods. The scattered intensity revealed a strong upturn at low values of the wave vector (q) for mucin solutions at pH 2 and pH 4, which suggests the evolution of large association domains. At these pH values, a flow-induced anisotropy in the 2D SALS patterns in the form of elliptical shapes was observed at high shear rates.},
  author       = {Maleki, Atoosa and Lafitte, Géraldine and Kjoniksen, Anna-Lena and Thuresson, Krister and Nyström, Bo},
  issn         = {1873-426X},
  keyword      = {light scattering,rheo-small angle,purified pig gastric mucin,dynamic light scattering,effect of pH,associations},
  language     = {eng},
  number       = {2},
  pages        = {328--340},
  publisher    = {Elsevier},
  series       = {Carbohydrate Research},
  title        = {Effect of pH on the association behavior in aqueous solutions of pig gastric mucin},
  url          = {http://dx.doi.org/10.1016/j.carres.2007.10.005},
  volume       = {343},
  year         = {2008},
}