Model cell membranes: Techniques to form complex biomimetic supported lipid bilayers via vesicle fusion

Abstract

Vesicle fusion has long provided an easy and reliable method to form supported lipid bilayers (SLBs) from simple, zwitterionic vesicles on siliceous substrates. However, for complex compositions, such as vesicles with high cholesterol content and multiple lipid types, the energy barrier for the vesicle-to-bilayer transition is increased or the required vesicle-vesicle and vesicle-substrate interactions are insufficient for vesicle fusion. Thus, for vesicle compositions that more accurately mimic native membranes, vesicle fusion often fails to form SLBs. In this paper, we review three approaches to overcome these barriers to form complex, biomimetic SLBs via vesicle fusion: (i) optimization of experimental conditions (e.g., temperature, buffer ionic strength, osmotic stress, cation valency, and buffer pH), (ii) α-helical (AH) peptide-induced vesicle fusion, and (iii) bilayer edge-induced vesicle fusion. AH peptide-induced vesicle fusion can form complex SLBs on multiple substrate types without the use of additional equipment. Bilayer edge-induced vesicle fusion uses microfluidics to form SLBs from vesicles with complex composition, including vesicles derived from native cell membranes. Collectively, this review introduces vesicle fusion techniques that can be generalized for many biomimetic vesicle compositions and many substrate types, and thus will aid efforts to reliably create complex SLB platforms on a range of substrates.

Molecular-level insights of early-stage prion protein aggregation on mica and gold surface determined by AFM imaging and molecular simulation

“…[32] Meanwhile, mica surface is commonly used as substrate for lipid bilayers, modeling the native cell membrane with its unique properties of being atomically flat, and negatively-charged. [33] Several investigations using in situ AFM reported aggregates A c c e p t e d M a n u s c r i p t of amyloid proteins with varied morphologies on mica surface. [34,35] Therefore, application of both solid surfaces as model systems provide the opportunity to elucidate how specific surface environments influence the architectural features of early-stage PrP aggregates.…”

Total internal reflection fluorescence microscopy for determination of size of individual immobilized vesicles: Theory and experiment

“…8 Such systems can be fabricated via adsorption of vesicles without or with subsequent spontaneous or peptide-induced rupture 8,9 or via the "solventassisted" procedure. 10 The corresponding mass uptake can be determined optically by ellipsometry, waveguide lightmode spectroscopy and surface plasmon resonance, [11][12][13] or by quartz crystal microbalance.…”

Interaction of Extracellular Vesicles with Si Surface Studied by Nanomechanical Microcantilever Sensors

“…While spreading of synthetic liposomes and proteoliposomes on flat surfaces to form SLBs is extensively studied [52,53], the present work is among the first attempts to extend this research to EVs. EV layers may be used as novel accurate models to investigate properties of biological membranes.…”