Curvophilic-curvophobic balance of monoalkyl-mannosides determines the magnitude of disturbance promoted in synthetic bilayers

The principles governing surfactant-lipid interactions, involved in biological membrane solubilization and reconstitution processes, are a topic of great interest in the field of membrane biochemistry and biophysics. Among non-ionic surfactants, which are extensively used in purification, characterization and reconstitution of membrane proteins and for reconstitution studies, sugar-based surfactants are particularly interesting because, besides being considered “green” chemicals, they have very good physical-chemical and dermatological properties. Mixtures of non-ionic sugar-based surfactants and phospholipids can result in interesting aggregates (micelles or vesicles) with promising applications in drug delivery, as a biocompatible carrier system. In this work, we studied how the incorporation of three different monoalkyl mannoside derivatives in synthetic bilayers modify their physical-chemical properties (transition temperature, fluidity) or promotes their solubilization. Determinations were made by using fluorescence spectroscopy, colorimetry and optical density measurements. Our results showed first that the mannoside derivatives behave different from other alkyl monosaccharides previously reported, such as glucosides and galactoside. Second, the ability of mannose derivatives to solubilize membranes dependents on its structure (length of alkyl chain) and the affinity between mannose derivatives and the lipid bilayer does not only depend on their Hydrophilic Lipophilic Balance, but also on the effect of the packing capabilities of the hydrophilic sugar head.