Controlled self-assembly of stomatosomes by use of single-component fluorinated dendritic amphiphiles

Abstract

A series of novel non-ionic amphiphiles with dendritic oligoglycerol head groups of different generations ([G1]-[G3]) and lipophilic/fluorophilic tail segments, comprising single or double tail alkyl chains, C8F17-perfluoro rod segments as well as flexible spacer groups of different lengths were designed and synthesized. We expected that the differences in the size of the dendritic head groups in combination with perfluorinated segments would have an impact on the supramolecular structures formed in aqueous solution if compared with the hydrogenated analogues. Investigating the self-assembly behavior mainly by cryogenic transmission electron microscopy (cryo-TEM) and cryo-electron tomography (cryo-ET) we found as a new result the formation of perforated bilayer vesicles (stomatosomes) and bicontinuous network structures. Surprisingly, we have observed stomatosome formation by self-assembly of single component fluorinated dendritic amphiphiles. These assembly structures turned out to be extremely robust against harsh conditions, although there are strong indications that they represent non-equilibrium structures, which eventually transform into a bicontinuous cubic network structure of double diamond symmetry. In general, the molecular asymmetry of amphiphiles tuned by chemical design induced the expected trend from spherical micelles through worm-like micelles to perforated bilayers and three-dimensional network structures.

Unusual Structures of Interpolyelectrolyte Complexes: Vesicles and Perforated Vesicles

“…These morphologies occupy the area between the vesicles and the so-called structured solid particles. The hollow particles with porous shells are reported in numerous studies of amphiphilic systems and referred to as cage-like micelles, stomatosomes, or perforated vesicles [49][50][51][52][53]. As a result of the further worsening of the solvent quality, the density of the polycation groups falls to zero in the central part of the complex.…”

Advances of Non-Ionic Surfactant Vesicles (Niosomes) and Their Application in Drug Delivery

“…In niosomes, non-ionic surfactants are the main ingredient, rather than phospholipids, which is the primary component in liposomes. Non-ionic surfactants used in the niosomes are amphipathic, including terpenoids [17], polysorbates [18], Spans [19], alkyl oxyethylenes (usually from C12 to C18) [20,21] and so on. Squalene, as a member of the terpenoid family, is a natural lipid.…”

Non-ionic small amphiphile based nanostructures for biomedical applications

“…In another study, the morphology of similar type of uorinated dendritic amphiphiles was investigated, in which the curvature of the single molecule determined the shape of selfassembled aggregates. 67 In contrast to simple alkyl chain, uorinated chain gives extra stiffness favouring planar architecture. All G3 amphiphiles irrespective of the number of per-uoro chain as well as single-tailed G2 amphiphiles, selfassembled into spherical micelles (Fig.…”