title: Interaction strength between proteins and polyelectrolyte brushes: a small angle X-ray scattering study.
abstract: We present an investigation of β-lactoglobulin adsorption onto spherical polyelectrolyte brushes (SPBs) by small angle X-ray scattering (SAXS). The SPB consists of a polystyrene core onto which long chains of poly(styrene sulfonate) are grafted. The amount and the distribution of proteins adsorbed in the brush layer at low ionic strength can be derived from SAXS. The analysis of the SAXS data reveals additionally that some of the protein molecules form aggregates of about six monomers in the adsorbed state. Furthermore, the position and the amount of slightly bound protein can be detected by the combination of the SAXS results and the SPB loading after extensive ultrafiltration. The total amount of adsorbed protein is compared to data derived from isothermal titration calorimetry. The comparison of both sets of data demonstrates that the protein molecules in the inner layers of the spherical polyelectrolyte brush are firmly bound. Proteins located in the outer layers are only weakly bound and can be washed out by prolonged ultrafiltration.
authors: Soft Matter and Functional Materials, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin, Germany.
authors: Katja
authors: K
authors: Henzler
authors: Björn
authors: B
authors: Haupt
authors: Sabine
authors: S
authors: Rosenfeldt
authors: Ludger
authors: L
authors: Harnau
authors: Theyencheri
authors: T
authors: Narayanan
authors: Matthias
authors: M
authors: Ballauff
mesh_terms: D004573:Electrolytes / Q000737:chemistry; D007782:Lactoglobulins / Q000737:chemistry*; D011137:Polystyrenes / Q000737:chemistry*; D053838:Scattering, Small Angle; D014961:X-Ray Diffraction
chemical_list: D004573:Electrolytes; D007782:Lactoglobulins; D011137:Polystyrenes; C003321:polystyrene sulfonic acid