Gram-negative (GN) bacteria are equipped with a cell wall constituted by a complex matrix of lipids, proteins and glycans, which forms a rigid protective layer against the environment. One major component is an outer membrane glycolipid, the lipopolysaccharide (LPS). The unique properties of the large and amphiphilic LPS molecules have major impact on GN outer membrane characteristics and understanding of their role in the cell wall is important for various fields such as electric field inactivation of bacteria, exploration of new antibiotics or bacteriophage treatments. Due to its high complexity, there is a great demand for reduced and defined models of the GN outer membrane. Giant unilamellar vesicles (GUVs) are versatile platforms for various model membranes. GUVs are synthetic membrane systems that allow the investigation of membrane properties, while controlling parameters such as membrane composition, surrounding media and temperature. Furthermore, effects of external factors like ionic strength, hydrodynamic flows and electromagnetic fields can be studied. In contrast to eukaryotic membranes, models of the Gram-negative outer membrane are scarce. In this project, we aim at generating an in vitro GUV model of the Gram-negative bacterial outer membrane and applying it in bacteriophage interaction studies to understand the molecular mechanism of the bacteriophage infection machinery. We use an adapted method based on inverted emulsions to integrate LPS in the GUV outer leaflet and present a detailed analysis of the resulting LPS-GUVs. We describe their membrane asymmetry and membrane material properties such as bending rigidity and edge tension. Moreover, we describe LPS-GUV stability in the electric field in comparison to conventional phospholipid vesicles.

Bacterial mimetic systems for studying bacterial inactivation and infection

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.