Glucosomes: Glycosylated Vesicle‐in‐Vesicle Aggregates in Water from pH‐Responsive Microbial Glycolipid

Abstract

Vesicle‐in‐vesicle self‐assembled containers, or vesosomes, are promising alternatives to liposomes because of their possible hierarchical encapsulation and high stability. We report herein the first example of sugar‐based vesicles‐in‐vesicles, which we baptize glucosomes. These were prepared by using a natural microbial glycolipid (branched C22 sophorolipid) extracted from the culture medium of the yeast Pseudohyphozyma bogoriensis. Glucosomes spontaneously formed in water between pH 6 and pH 4 at room temperature, without the requirement of any additive. By means of pH‐resolved in situ small angle X‐ray scattering, we provided direct evidence for the vesicle‐formation mechanism. Statistical treatment of the vesicle radii distribution measured by cryo‐tansmission electron microscopy by using a derived form of the Helfrich bending free‐energy expression provided an order of magnitude for the effective bending constant (the sum of the curvature and the saddle‐splay moduli) of the lipid membrane to K=(0.4±0.1) k B T. This value is in agreement with the bending constant measured for hydrocarbon‐based vesicles membranes.

Biomedically Relevant Applications of Bolaamphiphiles and Bolaamphiphile-Containing Materials

“…An emerging class of BAs are those derived from sophorolipids (Cuvier et al, 2015 ; Baccile et al, 2017 ). Sophorolipids are a renewable class of glycolipid biosurfactant derived from Starmerella bombicola yeast.…”

Antibacterial properties of glycosylated surfaces: variation of the glucosidal moiety and fatty acid conformation of grafted microbial glycolipids

“…For its peculiar morphology, it is named "branched sophorolipid". The compound used in this work was recently produced 43 according to a published procedure 44 45 as a mixture of hydroxyled and non-hydroxyled congeners. The hydrolyzed cellobioselipids (CLh) were obtained by alkaline hydrolysis and further acidification at neutral pH.…”

Multivesicular Vesicles: Preparation and Applications

“… Schematic representation of Method (12) , the formation of MVVs by using a pH‐sensitive amphiphile that is known to undergo a micelle‐vesicle transformation on lowering the pH value from high to intermediate (partial protonation of carboxylate) [73] . Vesicles containing internal vesicles, i. e., MVVs, may form during this process, as was shown for a specific amphiphilic glycolipid and pH≈6 [73] …”

“…Oleic acid is an example of a pH‐sensitive amphiphile. Depending on the chemical structure of pH‐sensitive amphiphiles, the transformation of micelles into vesicles may occur such that the obtained vesicles to a large extent contain internal vesicles, i. e., MVVs are formed, [73] see Figure 18. This was demonstrated to occur under certain conditions (e. g. pH ≈6) with a specific type of pH‐sensitive glycolipid (carrying a carboxylic acid moiety as in the case of oleic acid) [72] .…”