AVS 49th International Symposium
    Biomaterials Tuesday Sessions
       Session BI-TuP

Paper BI-TuP5
Interaction of Poly(L-Lysine)-g-poly(ethylene glycol) with Negatively Charged Supported Phospholipid Bilayers

Tuesday, November 5, 2002, 5:30 pm, Room Exhibit Hall B2

Session: Biointerfaces and Surfaces I
Presenter: F. Rossetti, Swiss Federal Institute of Technology
Authors: F. Rossetti, Swiss Federal Institute of Technology
I. Reviakine, University of Houston
G. Csucs, Swiss Federal Institute of Technology
S.M. De Paul, Swiss Federal Institute of Technology
J. Vörös, Swiss Federal Institute of Technology
N.D. Spencer, Swiss Federal Institute of Technology
M. Textor, Swiss Federal Institute of Technology
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The goal of the study presented in this poster is to develop a general, one-step method for modifying the surfaces of different types of vesicles. The proposed idea is to coat negatively charged phospholipid or polymeric vesicles with functionalised Poly(L-Lysine)-g-poly(ethylene glycol) (PLL-g-PEG), a polyelectrolyte with a positively charged backbone and protein-resistant ("stealth"@footnote 1@) side chains. Negatively charged supported phospholipid bilayers (SPBs) were used to investigate the adsorption behaviour of PLL-g-PEG as a function of charge density. The main investigation methods used were the Quartz Crystal Microbalance (QCM-D, including measurement of dissipation) and fluorescence microscopy. The SPB system used consisted of mixtures of a zwitterionic phospholipid (dioleyl phosphatidyl choline - DOPC) and a negatively charged phospholipid (dioleyl phophatildyl serine - DOPS) in a range from 0 (neutral SPB, used as a control) to 18 mol-%. Effects of the buffer composition on the adsorption process (with particular attention to the ionic strength) and the presence or absence of Ca@super 2+@ ions, which were found to be crucial for the formation of an SPB from DOPC:DOPS vesicles, were also considered. @FootnoteText@ @footnote 1@ Woodle, M.C., Lasic D.D., Biochim. Biophis. Acta, 1992, 1113, 171-199.