Supported lipid membranes have been used as a model system to study biological membrane behavior and the structure and function of membrane proteins and receptors. However, integral membrane proteins incorporated into lipid bilayers that are directly supported on hydrophilic substrates suffer from non-physiological interactions with the solid support. This often causes loss of protein mobility and function.
To alleviate these problems, we have been developing a new, DNA-tethered lipid bilayer to separate the membrane from surface interactions, thereby providing a more favorable environment for integral membrane proteins. Our evolving strategy to make this system is first to tether giant vesicles to either a glass-supported lipid membrane or DNA-functionalized surface by complementary DNA using DNA-lipid conjugates which we have developed. These tethered giant vesicles rupture and form planar tethered lipid bilayer patches.  With this system, we will study the properties of the tethered membranes in varying conditions such as different lengths and number of DNA. A fluid tethered lipid membrane on top of another is a good model for cell-to-cell junction interactions. Interesting topological and possibly composition domains are observed and these can be used to obtain a deeper physical picture of complex membrane-membrane interactions.