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Effect of the Chemical Structure of Ionic Glycolipids on Their Lyotropic Aqueous Phase Behavior

Year: 2025

Type: article

Abstract: High Resolution Image Download MS PowerPoint Slide This study examines the self-assembly and lyotropic aqueous phase behavior of galactose- (GC) and rhamnose-based (RC) bioinspired glycolipids with C 10 and C 14 alkyl chains using small-angle X-ray scattering and wide-angle X-ray scattering measurements. In the isotropic micellar regime (L 1 ), ellipsoidal micelles were identified, with their size and aggregation number mainly controlled by the surfactant alkyl chain length. As the concentration increases, both GC and RC systems form hexagonal (H 1 ) mesophases, with the C 14 homologues exhibiting a broader stability range of H 1 and crystallizing above 80 wt %. Notably, above 95 wt % RC10 assembles into an additional bicontinuous cubic Ia3d phase, which was not observed in the GC systems. Phase boundary diagrams further indicate that the presence of rhamnose, with fewer hydroxyl groups and weaker hydrogen-bonding ability, favors mesophase ordering at lower concentrations, while galactose enhances hydration and expands the L 1 domain. At higher glycolipid concentrations, however, headgroup interactions may alter this trend, and the hydroxyl-rich galactose tends to promote crystallization, while rhamnose maintains the H 1 mesophase up to a more concentrated region. Overall, these findings demonstrate that bioinspired glycolipid self-assembly depends on a balance of contributions from their alkyl chains and sugar headgroups, transitioning from a sugar solubility-driven mechanism in L 1 to prevailing sugar–sugar interactions in the concentrated regime.

Source: ACS Omega

DOI: 10.1021/acsomega.5c08922

Authors: Giuliana Valentini, Tomás S. Plivelic, Paulo R. A. F. Garcia, Shinji Kihara, Ben J. Boyd, Watson Loh