Characterization of lipid bilayers adsorbed to functionalized air/water interfaces

Lipid bilayers immobilized in planar geometries, such as solid-supported or floating bilayers, have enabled detailed studies of biological membranes with numerous experimental techniques, notably X-ray and neutron reflectometry. However, the presence of a solid support also has disadvantages as it complicates the use of spectroscopic techniques as well as surface rheological measurements that would require surface deformations. Here, in order to overcome these limitations, we investigate lipid bilayers adsorbed to inherently soft and experimentally well accessible air/water interfaces that are functionalized with Langmuir monolayers of amphiphiles. The bilayers are characterized with ellipsometry, X-ray scattering, and X-ray fluorescence. Grazing-incidence X-ray diffraction reveals that lipid bilayers in a chain-ordered state can have significantly different structural features than regular Langmuir monolayers of the same composition. Our results suggest that bilayers at air/water interfaces may be well suited for fundamental studies in the field of membrane biophysics.

Automated summary

This study investigates the characteristics of lipid bilayers adsorbed to soft air/water interfaces functionalized with amphiphilic Langmuir monolayers. The results show that chain-ordered lipid bilayers have significantly different structural features compared to regular Langmuir monolayers. This suggests that bilayers at air/water interfaces are well suited for fundamental studies in the field of membrane biophysics.