Adsorption of lysozyme, beta-casein and their layer-by-layer formation on hydrophilic surfaces: Effect of ionic strength
2010 (English)In: Colloids and Surfaces B: Biointerfaces, ISSN 0927-7765, E-ISSN 1873-4367, Vol. 77, no 1, 1-11 p.Article in journal (Refereed) Published
The adsorbed amount and layer structure of lysozyme, beta-casein and mixed layers of the two proteins were studied on hydrophilic silica and quartz surfaces using the following techniques: ellipsometry, quartz crystal microbalance with dissipation monitoring (QCM-D) and total internal reflection fluorescence (TIRF). Particular emphasis was put on the effect of solution ionic strength on the layer formation. Both lysozyme and beta-casein showed a higher affinity for the silica surface when adsorbed from a solution of low ionic strength even though beta-casein and silica are negatively charged at the pH used. No beta-casein remained adsorbed after rinsing with a 150 mM buffer solution. The adsorbed amount of lysozyme on silica exceeded a monolayer coverage irrespective of the solution conditions and displayed a rigid structure. beta-Casein forms more than a single layer on pre-adsorbed lysozyme; an inner flat layer and an outer layer with an extended structure, which largely desorbs on rinsing. The build-up through sequential adsorption of lysozyme and beta-casein is favoured at intermediate and high ionic strength. The total adsorbed amount increased slightly with each deposition cycle and the mixed lysozyme/beta-casein layers contain higher amounts of protein compared to those of pure lysozyme or beta-casein. Sequential adsorption gives rise to a proteinaceous layer consisting of both lysozyme and beta-casein. The protein layers are probably highly interpenetrated with no clear separation between them.
Place, publisher, year, edition, pages
2010. Vol. 77, no 1, 1-11 p.
Lysozyme, beta-Casein, Layer-by-layer, Protein adsorption, Multilayers, Ellipsometry, QCM-D, TIRF, Solvent content
IdentifiersURN: urn:nbn:se:kth:diva-14272DOI: 10.1016/j.colsurfb.2009.12.019ISI: 000276272100001ScopusID: 2-s2.0-77549086167OAI: oai:DiVA.org:kth-14272DiVA: diva2:331988
QC 201007292010-07-292010-07-292016-05-18Bibliographically approved