Biomimetic surface modification with bolaamphiphilic archaeal tetraether lipids via liposome spreading

Abstract

Through investigations of the self-assembly behavior of three different tetraether lipids, the authors successfully established a solid supported, biomimetic tetraether lipid membrane via liposome spreading. These bolaamphiphilic lipids are the main compound in membranes of archaea, extremophile microorganisms, which underwent an enormous adaptation to extreme conditions in their natural environment with regard to temperature, pH, and high salt concentrations. Starting from a mathematical point of view, the authors calculated hydrophilic–lipophilic balance values for each lipid and recognized a wide difference in self-assembly potentials relying on size and hydrophilic properties of the lipid head groups. These results were in good accordance with data generated by lipid experiments at the air–water interface applying a Langmuir–Blodgett film balance so that the self-assembly potential of two different tetraether lipids was found to be sufficient to form stable liposomes in aqueous media. Liposomes composed of the main phospholipid of the archaea strain Sulfolobus acidocaldarius fused covalently on silanized glass substrates and formed a monomolecular lipid layer with upright standing molecules at film consistent thicknesses of approximately 5 nm determined by ellipsometry and atomic force microscopy. This work can be considered as a basic strategy to find optimized lipid properties in terms of liposome formation and spreading in water, and it is the first report about archaeal liposome fusing on surfaces to establish a solid supported lipid monolayer.

Vesicular and Planar Membranes of Archaea Lipids: Unusual Physical Properties and Biomedical Applications

“…The sugar moieties (mainly gulose, [ 134 ]) on T. a cidophilum tetraether lipids, on the other hand, were removed to yield the bare hydrophobic core, which were then reacted with cyanuric chloride at both polar headgroups. When cyanuric chloride-activated caldarchaeols in aqueous solution are spread to the solid support [ 135 ], the cyanuric chloride at one of the two polar lipid headgroups can react with the amino groups on the substrate, followed by self-assembly to form planar lipid membranes on the substrate surface. The cyanuric acid at the other polar end of tetraether lipids can be further chemically modified to meet various application needs [ 133 ].…”

Amine end-functionalized poly(2-ethyl-2-oxazoline) as promising coating material for antifouling applications

“…The main phospholipid included in dried biomass of Sulfolobus acidocaldarius was isolated and puried as described earlier. 39 The head-groups of the extracted tetraether lipid were activated by reuxing with cyanuric chloride over 1 week in dry chloroform/methanol (1 : 1).…”

“…TEL coating was performed via liposome spreading in a PTFE reaction chamber by incubation with a freshly prepared lipid emulsion at 70 C overnight. 39 Finally, the coated substrates were sonicated in chloroform for 10 minutes and dried with pressurized air. In a next step, the PEtOx were immobilized on the TEL-coated glass by coupling the amine end group of the polymer with the cyanuric chloride moiety of the TEL.…”

“…bipolar membrane spanning lipids from thermoacidophilic archaea, were presented as an interesting new class of linker molecules. [34][35][36][37][38][39] By a simple selfassembling process, a stable, highly ordered impermeable TEL monolayer ($4 nm) with biomembrane-like properties is formed. The covalent immobilization of this thin lipid layer on surfaces can be achieved easily when the lipid headgroups are functionalized with cyanuric chloride.…”

“…The covalent immobilization of this thin lipid layer on surfaces can be achieved easily when the lipid headgroups are functionalized with cyanuric chloride. [35][36][37]39 An outstanding property of TELs is their excellent stability against oxidation, acidic and basic hydrolysis as well as biodegradation, which is based on the fully saturated character of the methyl branched alkyl chains. 34 Moreover, biocompatibility analyses revealed that TELs are both nontoxic and immunologically inert and, additionally, exhibit antifouling activity.…”