AVS 51st International Symposium
    Biomaterial Interfaces Tuesday Sessions
       Session BI-TuA

Paper BI-TuA5
Construction and Characterization of Planar Lipid Bilayers Supported on Conductive Thin Polymer Films: Toward Artificial Photosynthetic Supramolecular Devices

Tuesday, November 16, 2004, 2:40 pm, Room 210D

Session: Biomembranes on a Chip
Presenter: L. Wang, The University of Arizona
Authors: L. Wang, The University of Arizona
T. McBee, The University of Arizona
S. Marikkar, The University of Arizona
C. Ge, The University of Arizona
N. Armstrong, The University of Arizona
S. Saavedra, The University of Arizona
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We are developing a new type of biomimetic photosynthetic device based on a photoactive lipid bilayer supported on a planar optical waveguide electrode overcoated with indium-tin oxide (ITO). The bilayer serves as a host for incorporation of artificial photosynthetic centers, which are prepared by Moore, Gust, and Moore (Arizona State University). A water-swollen, conductive polymer cushion is used to couple the bilayer to the ITO surface. The polymer cushion is required to planarize the ITO support and render it compatible with vesicle fusion, as well as act as a transducer of light-generated proton flux across the lipid layer, so that changes in flux can be detected both electrochemically and spectroscopically. In this presentation, we will summarize recent progress in preparation and characterization of lipid bilayers deposited on conductive polymer films composed of poly(aniline) (PANI) and poly(acrylic acid) (PAA), which are deposited by layer-by-layer self-assembly on ITO. A variety of lipid compositions, polymer compositions, and assembly conditions have been compared. An array of methods has been used to characterize these assemblies, emphasizing the diffusive properties of the lipid components, the spectroscopic and electrochemical responses of the PANI/PAA film, and the barrier properties of the lipid layer. Different lipid systems exhibit different diffusive properties; these appear to be correlated with the degree to which the potentiometric response of the PANI/PAA is blocked by lipid bilayer deposition. Egg phosphatidylcholine/cholesterol appears to form a continuous, nearly pinhole free bilayer on 2(PAA/PANI)/ITO, which is attributed to the role of cholesterol as a stabilizer in supported lipid films.