AVS 51st International Symposium
    Biomaterial Interfaces Wednesday Sessions
       Session BI1-WeM

Paper BI1-WeM5
Supramolecular Structure of Adsorbed Collagen Layers and Influence on Endothelial Cells Behavior

Wednesday, November 17, 2004, 9:40 am, Room 210D

Session: Cell-Surface Interactions
Presenter: C.C. Dupont-Gillain, Universitat Catholique de Louvain, Belgium
Authors: C.C. Dupont-Gillain, Universitat Catholique de Louvain, Belgium
E. Gurdak, Universitat Catholique de Louvain, Belgium
Z. Keresztes, Universitat Catholique de Louvain, Belgium
P.G. Rouxhet, Universitat Catholique de Louvain, Belgium
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The aim of this study is to examine the supramolecular organization of adsorbed collagen and to evaluate its influence on endothelial cells, thereby increasing our understanding of cell-material interactions. Collagen was adsorbed on polystyrene (PS) and plasma-oxidized PS (PSox) in different conditions, likely to affect the supramolecular structure of the adsorbed layers. The collagen layers and their mechanism of formation were examined using atomic force microscopy, quartz crystal microbalance, X-ray photoelectron spectroscopy and radiolabeling. On PS, the adsorbed collagen molecules leave protruding segments in solution, allowing fibril formation at the interface; this increases with concentration and with time. Dewetting of the collagen layer leads to the formation of discontinuous layers with a net-like nanopattern. On PSox, collagen mainly forms a felt of lying molecules. The adhesion of human umbilical vein endothelial cells (HUVEC) was studied on collagen layers adsorbed on PS or PSox and presenting a diversity of supramolecular structures. In presence of serum, HUVEC cells could not adhere to PS. After adsorption of a smooth collagen layer, cell adhesion became high, and increased with the adsorbed amount. However, the formation of fibrils at the interface provoked a decrease of cell spreading. The last trend was also observed on PSox. This may be related to the accessibility of recognition sites, which could be hidden once collagen forms fibrils. In contrast, the spreading of HUVEC cells was enhanced on discontinuous collagen layers compared to smooth, continuous ones. In this case, collagen association was triggered by dewetting, which could change the availability of recognition sites. Moreover, the discontinuous pattern could stimulate the organization of cell surface receptors, or allow coadsorption of proteins secreted by the cells. Further work includes antibody assays to assess the availability of recognition sites on adsorbed collagen.