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

Leonor Pérez-Fuentes,Carlos Drummond,Jordi Faraudo,Delfi Bastos-González

doi:10.3390/ma10080893

Abstract

Here, we study films of proteins over planar surfaces and protein-coated microspheres obtained from the adsorption of three different proteins (-casein, -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 -lactoglobulin form compact monolayers, almost without interstices between the proteins. However, -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.

Highlights

Protein adsorption is a basic step in many natural processes and biomedical applications such as drug delivery [1] or disease detection [2,3]
In this study, we have considered protein films of β-casein, β-lactoglobulin and bovine serum albumin (BSA) in order to compare films made of proteins with similar sizes and different secondary structures (β-casein vs. β-lactoglobulin) and compare with those made of globular proteins with different sizes (β-lactoglobulin vs. BSA)
We first consider our results for β-casein in implicit solvent at neutral pH and 298 K without the adsorbing surface, and we will describe the results of molecular dynamics (MD) simulations of adsorption onto a surface

Summary

Introduction

Protein adsorption is a basic step in many natural processes and biomedical applications such as drug delivery [1] or disease detection [2,3]. The properties of a protein film (coverage, protein orientation and conformation, etc.) strongly depend on the nature of the interaction between the protein and the surface. This is due to the fact that proteins do not usually behave like rigid particles [12], and most proteins do not attach to or detach from a surface with certain adsorption and desorption probabilities. Proteins are complex objects able to change conformation, deform, interact in different ways over the surface

Methods

Results

Conclusion