AVS 52nd International Symposium
    Biomaterial Interfaces Monday Sessions
       Session BI-MoP

Paper BI-MoP29
Calcium Ion Free Supported Lipid Bilayer Formation by Giant Vesicle Fusions

Monday, October 31, 2005, 5:00 pm, Room Exhibit Hall C&D

Session: Biomaterial Interfaces Poster Session
Presenter: Y.-H. Kim, The Graduate University for Advanced Studies, Japan
Authors: Y.-H. Kim, The Graduate University for Advanced Studies, Japan
Md. Rahman, The Graduate University for Advanced Studies, Japan
R. Tero, Institute for Molecular Science , NINS, Japan
T. Urisu, Institute for Molecular Science , NINS, Japan
Correspondent: Click to Email
Supported membranes are the lipid bilayers supported on the solid substrate, which are commonly used as a model membrane for the in vitro study of the fundamental properties of biological membranes and various biotechnological applications. We have investigated the effect of the electrostatic attractive force between vesicles and the surface on the supported lipid bilayer formation using atomic force microscopy (AFM) and fluorescence microscopy. In most of the lipid bilayer formation by vesicle fusion, Ca@super 2+@ are added to the vesicle suspensions to induce the rupture of the vesicle. The lipid bilayer formation under the Ca@super 2+@ free is required in such cases of the study of Ca@super 2+@ effects on the membrane surface reactions. When the bare SiO@sub 2@ surface was incubated in the suspension of the negatively charged giant vesicle without Ca@super 2+@, extremely low surface coverage of lipid bilayer was observed due to the surface-vesicle charge repulsion. while, high coverage of lipid bilayer was observed when Ca@super 2+@(final concentration 5 mM) was added before incubation. The remarkable difference in the coverage of the lipid bilayer on the SiO@sub 2@ surface according to the existence of calcium ion can be explained in terms of the adsorption of giant vesicles. As to the formation of the lipid bilayer, the adsorption is the initial step, and therefore a stable and strong adsorption is necessary to form high coverage of the lipid bilayer. In case of the positively charged surface modified by Aminoproplydimethylethoxysilane, the high surface coverage of the lipid bilayer was obtained without adding Ca@super 2+@. The strong electrostatic attractive force between vesicles and the surface of opposite charge enhances the stable adsorption of negatively charged giant vesicles, which promotes the lipid bilayer formation. The control of the surface and the vesicle charge is an important factor to make a supported lipid bilayer without calcium ion.