Impact of RGD peptide density grafted onto Poly(ethylene terephthalate) on MC3T3 cell attachment

The aim of this study was to evaluate the impact of different densities on MC3T3 cells attachment onto poly(ethylene terephthalate) (PET) film surfaces. Biomimetic modifications were performed by means of a three-step reaction procedure: creation of COOH functions onto PET surface, coupling agent grafting and finally immobilization of peptides. The originality of this work consist, in one hand on quantifying RGD peptides densities grafted onto PET, and on the other hand on studying MC3T3 cells responses after seeding on such biomimetic surfaces. After each functionalization step, modifications were validated by several physico-chemical techniques: X-ray photoelectron spectroscopy allowed to prove the grafting and high-resolution mu-imager coupled with use of radiolabelled amino acids enabled the evaluation of peptides densities. Moreover, this last technique permit us to ensure stability of binding between peptides and polymer. The efficiency of this new route for biomimetic modification of PET surface was demonstrated by measuring the adhesion at 15 h of osteoblast like cells. Study of cellular comportement was realised by means of focal contact proteins (vinculin, actin) immunostaining.