AVS 46th International Symposium
    Biomaterial Interfaces Group Friday Sessions
       Session BI-FrM

Paper BI-FrM1
Topographical Polymorphism of a Phospholipid Monolayer

Friday, October 29, 1999, 8:20 am, Room 613/614

Session: Interface, Properties, and Modification
Presenter: W.R. Schief, University of Washington
Authors: W.R. Schief, University of Washington
L.A. Touryan, University of Washington
S.B. Hall, Oregon Health Sciences University
V. Vogel, University of Washington
Correspondent: Click to Email
Light scattering microscopy reveals previously undetected topographical complexity in lipid monolayers at the air/water interface. At a surface pressure (@pi@) of @pi@ = 13 mN/m at room temperature, following completion of the liquid-expanded (LE) -> liqu id-condensed (LC) transition, the LC phase of Dipalmitoylphosphatidylcholine (DPPC) develops corrugations within a region covering half the monolayer and surrounding flat, chiral-shaped domains. The scattered intensities of the domains and the surrounding region are analyzed in light of capillary wave theory. With compression over @pi@ = 20 mN/m, the corrugated region becomes decorated with nanoparticles through a reversible budding process. Beyond a threshold of @pi@ = 60 mN/m, the budding accelerates. A tomic force microscopy (AFM) on samples transferred to mica confirms the presence of multibilayer discs of diameter 15 - 150 nm. These findings provide new information on potential surface mechanisms of respiration, since a monolayer enriched in DPPC is widely thought to coat the lung.