pH-Dependent Chiral Vesicles from Enantiomeric Sodium 2,3-Bis(decyloxy) Succinate in Aqueous Solution

Abstract

Enantiomeric, twin-tailed, twin-chiral, sodium (2R,3R)-(+)-bis(decyloxy)succinate and sodium (2S,3S)-(-)-bis(decyloxy)succinate have been synthesized and characterized. Surface tension, conductivity, and steady-state fluorescence spectroscopic measurements confirmed the presence of two aggregation concentrations, namely, the critical micellar concentration (CMC) and the critical vesicle concentration (CVC). The compounds behaved as true surfactants, with a CMC of 0.05 mM, and formed vesicles spontaneously in aqueous solution at a CVC of 0.14 mM. The compounds formed myelin figures in contact experiments, suggesting the formation of bilayers in aqueous solution culminating into individual vesicles. The vesicles were of 500-800 nm size and formed egg shells, porous spheres, and multivesicular vesicles, confirmed from transmission electron microscopy and optical microscopic techniques. The vesicles were found to be pH sensitive, were stable in the pH range 6-8, and formed the insoluble diacid at acidic pH due to protonation of the carboxylate head groups.

Size, Charge, and Stability of Fully Serine‐Based Catanionic Vesicles: Towards Versatile Biocompatible Nanocarriers

“…We attribute the two critical aggregation points to the formation of different bulk aggregates, which coexist when the final plateau is attained. This type of behavior has been observed before in other surfactant mixtures49, 53–57 and we will return to it later.…”

Serine-based gemini surfactants with different spacer linkages: from self-assembly to DNA compaction

“…45 Accordingly, for the amine and conventional bis-quat gemini, the cac values correspond to a true critical micelle concentration, cmc, while for the amide and ester they are instead a critical vesicle concentration, cvc. [46][47][48][49][50][51] The rst break point that appears for the ester and amide surfactants may signal the formation of initial small aggregates (either micellar or vesicular), similar to what has been previously reported for other bilayer-forming surfactants. 48,[50][51][52] Table 1 shows the interfacial parameters obtained from the g-ln(m) curves, namely the cac (determined as the intersection points in Fig.…”

Micelle–Vesicle Transition of Fatty Acid Based Ion‐Pair Surfactants: Interfacial Evidence and Influence of the Ammonium Counterion Structure

“…[3][4][5][6] A possible transition from micelles to vesicles or vesicles to micelles, and its control, could be of great interest for practical applications (drug delivery or protein reconstruction) [7,8] and fundamental studies. [9][10][11] There are many examples of micellevesicle transition being induced by altering the solution condi-tions, temperature, [12,13] pH level, [14] surfactant concentration, [12,15] electrolyte concentration and nature, [16][17][18][19] or organic additives. [20][21][22][23] For example, micelle-vesicle transitions in catanionic surfactant systems are well-documented, and there are numerous possibilities for inducing such transitions.…”