AVS 52nd International Symposium
    Biomaterial Interfaces Thursday Sessions
       Session BI-ThA

Paper BI-ThA9
Investigations About the Formation of Supported Phospholipid Bilayers on Structured Surfaces

Thursday, November 3, 2005, 4:40 pm, Room 311

Session: Bionanotechnology
Presenter: B. Seantier, Chalmers University of Technology, Sweden
Authors: B. Seantier, Chalmers University of Technology, Sweden
I. Pfeiffer, Chalmers University of Technology, Sweden
M. Zaech, Chalmers University of Technology, Sweden
D. Sutherland, Chalmers University of Technology, Sweden
Correspondent: Click to Email
There has been a strong current interest in the interaction of lipid vesicles with different homogenous materials surfaces. A number of mechanisms have been discussed leading to the formation of Supported Phospholipid Bilayers (SPBs) (for example on flat SiO@sub 2@) or intact vesicles (for example on flat Au). In our study, we have utilized lithographically defined nanoscale patterns to investigate the role of local variations in surface topography and chemistry on vesicle-surface interaction. We have studied surfaces combining two chemistries (SiO@sub 2@ and Au) where the domain sizes are similar to or below the characteristic size of the vesicles. The mechanism of the SPB formation has been studied by varying parameters such as phospholipids composition, vesicles size and concentration, and the ionic strength of the buffer solution. Quartz Crystals sensor surfaces were structured using dispersed colloidal monolayer masks (d=100nm) and lift off pattern transfer giving pits with combinations of upper and lower surface (~20% of the total surface area) chemistries. 100 nm and 200 nm extruded vesicles of POPC and DMPC have been used to form SPBs (vesicle conc. range varied between 50 µM and 500 µM with and without CaCl@sub 2@). Parallel experiments with identical surfaces utilized Quartz Crystal Microbalance with Dissipation monitoring technique and the Atomic Force Microscopy technique providing time-lapse images of the SPBs formation. The results show a two step mechanism, different from the classical SPB formation, which cannot be explained by the superposition of the vesicle behavior on Au and SiO@sub 2@ surfaces. A complex mechanism involving trapping vesicles in holes and SPB formation at the pits is assumed. In the future perspectives, the size and the shape of the Au pits will be varied. This study should allow us to better understand the influence of the surface topography and chemistry on the SPB formation.