Effect of Supporting Polyelectrolyte Multilayers and Deposition Conditions on the Formation of 1-Palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine/1-Palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine Lipid Bilayers

Abstract

The formation of complete supported lipid bilayers by vesicle adsorption and rupture was studied in relation to deposition conditions of vesicles and underlying cushion formed from various polyelectrolytes. Lipid vesicles were formed from zwitterionic 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and negatively charged 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) in phosphate buffer of various pH with or without NaCl addition. Polyelectrolyte multilayer films (PEM) were constructed by sequential adsorption of alternately charged polyelectrolytes from their solutions-layer-by-layer deposition (LBL). The mechanism of the formation of supported lipid bilayer on polyelectrolyte films was studied by quartz crystal microbalance with dissipation monitoring (QCM-D) and atomic force microscopy (AFM). QCM-D allowed following the adsorption kinetics while AFM measurements verified the morphology of lipid vesicles and isolated bilayer patches on the PEM cushions providing local topological images in terms of lateral organization. Additionally, polyelectrolyte cushions were characterized with ellipsometry to find thickness and swelling properties, and their roughness was determined using AFM. It has been demonstrated that the pH value and an addition of NaCl in the buffer solution as well as the type of the polyelectrolyte cushion influence the kinetics of bilayer formation and the quality of formed bilayer patches.

Supported Lipid Bilayer Assembly on PEDOT:PSS Films and Transistors

“…This may indicate a mixed population of vesicles and lipid bilayer . Previous studies by Wlodek et al monitoring vesicle rupture on polyelectrolyte coated surfaces, have shown Δf and ΔD values of up to −82 Hz and 28 × 10 −6 , respectively, concluding that the high shifts are caused by abundant water trapped in hydrophilic regions . Further confirmation of the effect of thickness on vesicle adsorption and fusion is shown in Figure S3 of the Supporting Information.…”

Interfacial and structural characteristics of polyelectrolyte multilayers used as cushions for supported lipid bilayers

“…Thus, these results show that the amount of liposomes adsorbed, the kinetics of liposome fusion and rupture, as well as the final structure and amount of the obtained SLBs depended on the PEM cushion type, demonstrating the important role of the PEM properties in the SLB formation via vesicle fusion. 20 Our findings are in agreement with a number of previous studies. Renner et al 29 found that the degree of hydrophobicity and swelling of the anionic polymer cushions determined both the kinetics of the membrane formation and the mobility of the obtained SLB.…”

“…Considering the results for supported lipid bilayer formation on the top of PEI(PGA/PLL) 3 , PEI(PSS/PDADMAC) 3 and PEI(PSS/PEI) 3 discussed previously 20 and in the Introduction section, we can correlate the capacity of the SLB formation with the polar component of the surface free energy of polyelectrolyte cushion. While the kinetics of liposome deposition is the same for all the studied PEM supports (Fig.…”

“…Some key parameters include the polyelectrolyte type, ionic strength, pH and temperature in the solution, type of electrolyte used, deposition time, number of steps during the sequential adsorption, etc. 5 Different experimental techniques have been used to study PEM properties, such as quartz crystal microbalance QCM, 15 surface plasmon resonance (SPR) spectroscopy, 16 ellipsometry, 17 X-ray reflectometry (XRR), 18 neutron reflectometry (NR), 19 atomic force microscopy (AFM), 20 Fourier transform infrared (FTIR) spectroscopy, optical waveguide lightmode spectroscopy (OWLS), etc.. 5,12,14 These advantages of PEMs make them a promising candidate as a support for lipid bilayers. 21 Supported lipid bilayers (SLBs) are widely utilized as model cell membranes, 23,24 and in biosensors where they provide a biologically mimicking environment for functional biomolecules such as proteins with sensing activities, 25 interfacing artificial materials with biological system.…”

Biodegradable, Tethered Lipid Bilayer–Microsphere Systems with Membrane-Integrated α-Helical Peptide Anchors

“…27,28 This is likely due to an inhibition of rupture propagation. The surface roughness of PLGA microspheres prepared by solvent evaporation has been previously measured to be approximately 12 nm or below 29 which reaches the limit suggested Duarte and Raposo.…”