AVS 50th International Symposium
    Biomaterial Interfaces Wednesday Sessions
       Session BI+SS-WeA

Paper BI+SS-WeA5
Intact Vesicle Adsorption and Supported Biomembrane Formation from Vesicles in Solution Studied by a Combined SPR and QCM-D Instrument, and AFM

Wednesday, November 5, 2003, 3:20 pm, Room 307

Session: Biomolecular Surface Science and Microfluidics
Presenter: B. Kasemo, Chalmers University of Technology, Sweden
Authors: E. Reimhult, Chalmers University of Technology, Sweden
F. Höök, Chalmers University of Technology, Sweden
B. Kasemo, Chalmers University of Technology, Sweden
Correspondent: Click to Email
Two biomembrane model systems receiving high interest are unilamellar phospholipid vesicles and supported planar phospholipid bilayers. We have investigated the adsorption kinetics of small unilamellar POPC vesicles with a setup, combining the Quartz Crystal Microbalance with Dissipation technique and Surface Plasmon Resonance techniques in parallel. Using this instrument we have for the first time simultaneously and in real time measured the acoustic (hydrated) and optical (dry) mass for vesicle adsorption on SiO@sub 2@ and oxidized Au. These measurements have significantly extended our understanding of intact vesicle adsorption on surfaces, as a function of surface chemistry,@footnote 1@ temperature,@footnote 1,2@ vesicle size,@footnote 3@ and osmotic stress.@footnote 1@ We have been able to distinguish between the mass response due to adsorbing intact vesicles and that of planar bilayers formed on the surface via vesicle rupture. Furthermore, we have; determined the critical coverage required for vesicle rupture on SiO@sub 2@, obtained a measure of the amount of trapped water and deformation of intact vesicles on the surface, studied the kinetics of the final part of the supported planar bilayer formation process on SiO@sub 2@ and detected loss of lipids on its completion. The latter two are critical for the quality of the formed bilayer, i.e. limiting the number of defects. We also intend to present results from atomic force microscopy studies of vesicle adsorption on heterogenous (patterned) surfaces, with focus on the behavior at phase boundaries, separating planar bilayer forming and intact vesicle adsorbing areas. @FootnoteText@ @footnote 1@ E. Reimhult, F. Höök, and B. Kasemo, Langmuir 19, 1681 (2003)@footnote 2@ E. Reimhult, F. Höök, and B. Kasemo, PRE 66, 051905 (2002).@footnote 3@ E. Reimhult, F. Höök, and B. Kasemo, JCP 117, 7401 (2002).