Adsorption of Mefp-1: Influence of pH on adsorption kinetics and adsorbed amount
2012 (English)In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 379, 107-113 p.Article in journal (Refereed) Published
Mussel adhesive proteins have received considerable attention due to their ability to bind strongly to many surfaces under water. Key structural features of these proteins include a large number of 3,4-dihydroxyphenyl-L-alanin (DOPA) and positively charged lysine residues. We elucidate the effects of solution pH, in the pH range 3-9, on adsorption kinetics, adsorbed amount, and layer structure on silicon oxynitride by employing Dual Polarization Interferometry. As a comparison, the cationic globular protein lysozyme was also investigated. The zeta-potential of the silicon oxynitride substrate was determined as a function of pH, and the isoelectric point was found to be below pH 3. Mefp-1 is positively charged at pH < 10, and thus, the protein is expected to have an electrostatic attraction for the surface at all pH values investigated. The adsorbed amount and the initial adsorption rate were found to increase with solution pH, and no significant desorption occurred due to rinsing with pure water. The layer thickness after rinsing was 3-4 nm, except at pH 3, where the adsorption was limited to a small amount. Covalent cross-linking of the Mefp-1 layer with NaIO4 resulted in a small but significant compaction and increase in refractive index of the layer. The results are discussed in terms of the role of DOPA and electrostatic interactions for the adsorption of Mefp-1 to silicon oxynitride. (C) 2012 Elsevier Inc. All rights reserved.
Place, publisher, year, edition, pages
2012. Vol. 379, 107-113 p.
Mussel adhesive protein, Mefp-1, Dual Polarization Interferometry (DPI), Adsorption, Adsorption kinetics, Cross-linking, Silicon oxynitride, Zeta-potential
IdentifiersURN: urn:nbn:se:kth:diva-99056DOI: 10.1016/j.jcis.2012.04.040ISI: 000305592000017ScopusID: 2-s2.0-84861958400OAI: oai:DiVA.org:kth-99056DiVA: diva2:541579
QC 201207192012-07-192012-07-132012-07-19Bibliographically approved