Dual polarization interferometric and capillary electrophoretic analysis of supported lipid bilayer constructed on silica-based surface: Evaluation of its anti-protein adsorption effect

Abstract

Supported lipid bilayer (SLB) has been demonstrated as a model of cell membranes with prospective bioanalytical or biotechnological applications. In this study, the formation of SLB and their potential biofunctionality against protein adsorption were investigated by Dual Polarization Interferometry (DPI) and Capillary Electrophoresis (CE). DPI studies on different formulations of double-chained, zwitterionic phospholipidlipids, allow the process of bilayer formation to be followed in situ and in real time. Furthermore the anti-protein adsorption effect provided by the various formulated SLBs was examined by DPI. In addition, the SLB coatings of the same lipid formulations were subsequently employed in CE experiments as a pseudo-stationary phase for demonstrating more efficient separation of alkaline protein standard mixtures. SLB-assisted CE was found to be capable of separating 4 alkaline proteins (protonated at neutral pH). This study demonstrates the applicability of DPI to monitor the process of SLB formation; and our findings, obtained by both DPI and CE, confirm that the presence of the SLB reduced drastically the problematic interactions between cationic, alkaline proteins and the negatively charged silica capillary wall, leading to better recovery and efficient separation of the proteins under investigation.