Mimicking anhydrobiosis on solid supported lipid bilayers

The studies presented in this thesis focus on the synthesis of air-stable solid supported lipid bilayers by anhydrobiotic mechanisms. Supported lipid bilayers (SLBs) serve as platforms that mimic cellular membrane surfaces in appearance and behavior. One of the most attractive aspects of the SLB is that it exhibits two-dimensional fluidity that allows for individual components to rearrange as they would in actual cellular membranes. The one thing that would allow the SLB to become an ideal biosensor is the ability to remain stable in the absence of bulk water. As it stands now, unprotected SLBs are unstable in the presence of air causing the membrane to rearrange and delaminate from the surface. Several biological organisms utilize the process of anhydrobiosis to persevere in severe dehydrated states. Anhydrobiosis occurs when organisms employ large amounts of sugars, particularly disaccharides, to protect their cell membranes. The sugars, often released as a stress response, protect the membrane by replacing the water around the lipid headgroups while also interacting with other sugars to form a glass atop the bilayer. One of the most successful anhydrobiotic sugars has been trehalose, although other sugars have been evaluated and are capable of protecting lipid bilayers minimally. The experimental section of this thesis involves the creation of SLBs that are examined with and without the presence of sugar molecules. Essentially, the SLB was created, exposed to sugar solutions, dried, and subsequently rehydrated. Successful experiments occurred when rehydrated bilayers exhibited little damage and were mobile and functional. In addition to trehalose, several other mono- and disaccharides were used as were glycolipids, lipids with sugar headgroups. Upon the completion of all experiments it was clear that trehalose afforded the most protection of all species tested and that glycolipids do not sufficiently protect the membrane during rehydration. Therefore, the addition of a sugar such as trehalose to an SLB could allow for the creation of an air-stable biosensor that would be both practical and require little maintenance.