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Structure of lipid multilayers via drop casting of aqueous liposome dispersions

DOI: 10.1039/C6SM00369A DOI Help

Authors: Beatrice Sironi (University of Bristol) , Tim Snow (University of Bristol) , Christian Redeker (University of Bristol) , Anna Slastanova (University of Bristol) , Oier Bikondoa (ESRF) , Tom Arnold (Diamond Light Source) , Jacob Klein (Weizmann institute) , Wuge H. Briscoe (University of Bristol)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Soft Matter

State: Published (Approved)
Published: March 2016
Diamond Proposal Number(s): 1990 , 13139

Abstract: Solid supported lipid multilayers have been widely studied as model cell membranes and as a platform for novel materials. Conventionally, they are prepared from drop casting or spin coating of lipids dissolved in organic solvents, and lipid multilayers prepared from aqueous media have not been previously reported, due to extremely low lipid solubility (i.e. cmc ~10-9 M) in water. Here, the preparation of dioleoylphosphatidylcholine (DOPC) multilayers by drop casting aqueous small unilamellar and multilamellar vesicle or liposome (i.e. SUV and MLV) dispersions is reported on different surfaces, including mica, positively charged polyethylenimine (PEI) coated mica, and stearic trimethylammonium iodide (STAI) coated mica which exposes a monolayer of hydrocarbon tails. X-ray reflectivity (XRR) measurements using a unique “bending mica” method confirm the DOPC multilayer structure on all these substrates, and the influence of the substrate surface chemistry on the multilayer structure is discussed. We suggest that DOPC liposomes serve both as a delivery matrix where appreciable lipid concentration in water (~25 mg mL-1 or 14 mM, i.e. >107 cmc) is feasible, and as a structural precursor where the lamellar structure is readily retained on rupture of the vesicles at the solid surface upon solvent evaporation to facilitate rapid multilayer formation. Our results point towards a controlled preparation of ordered lipid multilayers by tailoring the liposome homogeneity and substrate surface properties, potentially offering a simple method for the inclusion of hydrophilic functional additives (e.g. drugs or nanoparticles) into lipid multilayer based hybrid materials.

Subject Areas: Chemistry, Biology and Bio-materials

Instruments: I07-Surface & interface diffraction

Other Facilities: ESRF