Adsorption of Milk Proteins (β-Casein and β-Lactoglobulin) and BSA onto Hydrophobic Surfaces

• Main Authors: Leonor Pérez-Fuentes, Carlos Drummond, Jordi Faraudo, Delfi Bastos-González
• Format: Article
• Language: English
• Published: MDPI AG 2017-08-01
• Series: Materials
• Subjects: proteins; QCM; MD simulations; hydrophobic effect; ion condensation; electrokinetic mobility
• Online Access: https://www.mdpi.com/1996-1944/10/8/893

Here, we study films of proteins over planar surfaces and protein-coated microspheres obtained from the adsorption of three different proteins ( β -casein, β -lactoglobulin and bovine serum albumin (BSA)). The investigation of protein films in planar surfaces is performed by combining quartz crystal microbalance (QCM) and atomic force microscopy (AFM) measurements with all-atomic molecular dynamics (MD) simulations. We found that BSA and β -lactoglobulin form compact monolayers, almost without interstices between the proteins. However, β -casein adsorbs forming multilayers. The study of the electrokinetic mobility of protein-coated latex microspheres shows substantial condensation of ions from the buffer over the complexes, as predicted from ion condensation theories. The electrokinetic behavior of the latex-protein complexes is dominated by the charge of the proteins and the phenomenon of ion condensation, whereas the charge of the latex colloids plays only a minor role.