Biological evaluation of RGD peptidomimetics, designed for the covalent derivatization of cell culture substrata, as potential promotors of cellular adhesion.

Our aim was to replace the proteins and peptides, generally used for the biocompatibilization of polymer substrata, with synthetic molecules mimicking the RGD (Arg-Gly-Asp) active sequence. Based on the (L)-tyrosine template, RGD peptidomimetics were constructed; one molecule 3 was equipped with an anchorage arm that allowed its covalent grafting on a culture substratum made from poly(ethylene terephthalate) (PET) microporous membrane. The amount of fixed molecules was readily determined by XPS, using a fluorine tag incorporated in the peptidomimetic structure. The binding of peptidomimetics 1-3 to the vitronectin (VN) and fibronectin (FN) receptors could not be revealed in a test of inhibition of MSC 80 cells adhesion, by the synthetic compounds in solution placed in competition with the adhesive proteins (VN and FN) coating polystyrene plates. However, the cell-attachment activity of peptidomimetic 3 was shown by culturing CaCo2 cells, in the absence of serum, on the PET substratum grafted with 3. The performance of this support was similar to that of PET grafted with the reference peptide RGDS (Arg-Gly-Asp-Ser), and only reduced by half comparatively to the PET grafted with FN.