Phase behavior and miscibility in lipid monolayers containing glycolipids

Abstract

Hypothesis: Glycolipids in biological membranes are ubiquitous and believed to be involved in the formation of ordered functional domains. However, our current knowledge about such glycolipid-enriched domains is limited because they are inherently difficult to characterize.

Experiments: We use grazing-incidence X-ray diffraction, isotherm measurements, and Brewster angle microscopy to investigate the phase behavior and miscibility in Langmuir lipid monolayers containing glycolipids.

Findings: Glycolipid-enriched domains give rise to distinct diffraction patterns that allow for a systematic structural investigation and reveal a rich phenomenology, ranging from near-complete demixing to the formation of mixed domains with unique features. The phase behavior is governed by the headgroup chemistry and by the length and saturation of the tails.

Keywords: Brewster-angle microscopy; Glycolipid-enriched domains; Grazing-incidence X-ray diffraction; Langmuir isotherm; Langmuir monolayer; Phase behaviour; Phase diagram; Phospholipid.