Using Lipopolysaccharides to Create 3-D Multicomponent Biomimetic Membranes on Solid Supports

Abstract

Cell membranes are complex, multi component systems that contain dynamic elements such as lipid rafts and protein rich domains. Lipid Bilayer Assemblies (LBAs) can be used as model membrane systems for investigating interactions and responses to different stimuli but the level of complexity that can be studied is limited. Previous studies have shown the ability to create these LBAs on glass microspheres as well as flat substrates. These microspheres introduce a new level of complexity by creating mobile samples that can be analyzed using new techniques and also provide a curved surface more similar to biological cells. In previous studies we have demonstrated that Lipopolysaccharides (LPS) from gram-negative bacteria can be used to pattern LBAs in a simple, iterative manner. In this study, we have applied this LPS-modification approach to introduce new elements into LBAs on glass microspheres. We have found that LPS can be used to form static holes throughout the membrane while keeping the membrane intact. These holes can be backfilled with proteins such as BSA, and lipids, allowing membrane repair and or introduction of new components into the system. This technique gives rise to a multicomponent system that can be manipulated while still maintaining lipid fluidity in three dimensions. These new findings are being used to better understand LPS-membrane interactions, lead to new approaches for potential biosensor design, and provide a new platform for investigating cell membrane interactions. Future directions include using these coated microspheres as an LPS biosensor that can be analyzed using flow cytometry, introducing additional components into the system, such as receptors, gel phase lipids, and complex proteins to investigate membrane interactions and binding events and exploring as a template for the generation of janus-type particles.