Stabilization of Lipid Membranes With Dendritic Polymers

Abstract : Ion channels incorporated into lipid bilayers can be used as chemical sensors; however, the lack of stability of these bilayers prevents their use in practical sensor devices. In this study, dendrimers were used to stabilize lipid membranes by making use of their high surface functionality and the capability of modifying that functionality. Silica surfaces were coated with submonolayers of dendritic polymers, followed by a lipid solution containing a small percentage of fluorescent lipid. The lipid was allowed to incubate on the surface, and then unbound lipid was rinsed off with water. Fluorescence microscopy and fluorometry were used to assess the lipid adsorption to the substrate surfaces. Amine-based dendritic polymers, including polyamidoamine and polyethyleneimines, stabilized the lipids the greatest amount due to positive interactions between the lipid head group and the amine dendrimer. Neutral zwitterionic lipids, such as phosphocholine, were stabilized to a greater extent than negatively charged lipids, probably because the latter were repelled from the negatively charged silica surface. Ion channels incorporated into lipid bilayers can be used as chemical sensors; however, the lack of stability of these bilayers prevents their use in practical sensor devices. In this study, dendrimers were used to stabilize lipid membranes by making use of their high surface functionality and the capability of modifying that functionality. Silica surfaces were coated with submonolayers of dendritic polymers, followed by a lipid solution containing a small percentage of fluorescent lipid. The lipid was allowed to incubate on the surface, and then unbound lipid was rinsed off with water. Fluorescence microscopy and fluorometry were used to assess the lipid adsorption to the substrate surfaces.