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Poly-acrylic Acid Brushes and Adsorbed Proteins

Reinhardt, Matthias ; Kreuzer, Martin ; Geue, Thomas ; Dahint, Reiner ; Ballauff, Matthias ; Steitz, Roland

In: Zeitschrift für Physikalische Chemie, 2015, vol. 229, no. 7-8, p. 1119-1139

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    Titre
    • Poly-acrylic Acid Brushes and Adsorbed Proteins
    Auteur
    • Reinhardt, Matthias. Helmholtz-Zentrum Berlin, Institute of Soft Matter and Functional Materials, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
    • Kreuzer, Martin. Helmholtz-Zentrum Berlin, Institute of Soft Matter and Functional Materials, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
    • Geue, Thomas. Paul Scherrer Institut, Laboratory for Neutron Scattering, 5210 Villigen, Switzerland
    • Dahint, Reiner. Ruprecht-Karls-Universität Heidelberg, Applied Physical Chemistry, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany
    • Ballauff, Matthias. Helmholtz-Zentrum Berlin, Institute of Soft Matter and Functional Materials, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
    • Steitz, Roland. Helmholtz-Zentrum Berlin, Institute of Soft Matter and Functional Materials, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
    Type de document
    • Postprint
    Langue
    • Anglais
    Publié dans
    • Zeitschrift für Physikalische Chemie, 2015, vol. 229, no. 7-8, p. 1119-1139. De Gruyter Oldenbourg
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:325861
    Summary
    Planar polyelectrolyte brushes are prepared by Langmuir-Schaefer based grafting of perdeuterated (styrene)49-b-(acrylic acid)222 block copolymer (dPS-b-PAA) to dPS pre-coated silicon supports with grafting density σPAA from 0.07 to 0.11 nm-2. The structure of the solvent-swollen brushes, i. e. the volume fraction profile of polymer segments, ϕPAA, as a function of altitude z from the grafting plane into the liquid phase is extracted from neutron reflectivity measurements. We find that for all cases investigated ϕPAA(z) resembles a Gaussian profile. Although very condensed, the PAA brushes can be loaded with bovine serum albumin (BSA). The integral amount of adsorbed BSA scales linearly with grafting density. We compare our z-resolved volume fraction profile ϕBSA(z) of BSA on PAA brushes with existing literature on that system. It is found that a cross-over takes place in the adsorption scheme from ternary compressive, where proteins can approach the grafting surface only by compressing the brush, to ternary insertive, where proteins enter the brush with only local perturbation of the concentration profile, as a function of RP/Hmax, where RP is the Stokes-Radius of the protein, and Hmax is the experimentally determined maximum height of the brush.