AVS 52nd International Symposium
    Biomaterial Interfaces Wednesday Sessions
       Session BI2-WeM

Paper BI2-WeM7
1-dimensionally Crosslinked Intra- and Interleaflet Bilayers for Cell Surface Studies

Wednesday, November 2, 2005, 10:20 am, Room 312

Session: Biomembranes and Spectroscopy
Presenter: R. Michel, University of Washington
Authors: R. Michel, University of Washington
M. Halter, University of Washington
G. Sather, University of Washington
E. Naeemi, University of Washington
D.G. Castner, University of Washington
Correspondent: Click to Email
Although supported lipid bilayers are increasingly used as model systems for biological coatings, they lack the high stability desired for use in ambient or ultrahigh-vacuum environment. Poly(hydroxyethyl methacrylate) (pHEMA) is a hydrogel used in many biomedical applications, most commonly in ophthalmic applications. By tethering lipid bilayers to a pHEMA support, we better mimic the natural environment of the implant. In this work, a twofold approach was employed to stabilize the supported lipid film to the pHEMA. The intra-leaflet stabilization is achieved by cross-linking part of the lipids via the hydrophobic tail using SH-dipalmitoylphosphatidylcholine (DPPC) /acryloyloxy-phosphatidylcholine. To stabilize the leaflet to the surface, dimyristoylphosphatidylethanolamine (DMPE) lipids are mixed with the intra-leaflet crosslinked lipids. The DMPE lipids are crosslinked to the pHEMA substrate via 1.1' carbonyldimidazole (CDI) activation of the pHEMA surface and attachment of the polar head group. Using X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), and fluorescence microscopy, we characterized the purity, composition, and degree of crosslinking of the bilayers. We find that use of these inter- and intra-leaflet crosslinking agents allow us to tailor the fluidity and rigidity of the supported lipid bilayers, which opens up new possibilities for protein incorporation and activity in these lipid bilayers.