Despite the high initial success rate with metallic stents for the treatment of a variety of vascular lesions, problems have included occlusion due to thrombus formation or intimal proliferation. Improving the biological behavior of these and other other implantable metallic devices may require the use of biomimetic peptide coatings which promote specific cellular responses at the biological-materials interface.
Thiol-terminated peptides, without the addition of a cysteine residue, were synthesized by a modification of standard solid phase methodology. Gold/mica or gold/glass surfaces were exposed for 6 hours at 23 °C to one of three peptide solutions: GRGD(βA)3YNH(CH2)2SH (RGD); (βA)6NH (CH2)2SH (bAla); or a 1:1 mix of both peptides. Peptide films were examined by external reflectance infrared (IR) spectroscopy and atomic force microscopy (AFM) which confirmed the presence of unique close-packed structures for bAla and the 1:1 mix. Endothelial cell proliferative, migratory, and adhesive behavior were evaluated using 3H-thymidine and 51Cr labeling techniques, respectively. Cell proliferation, migration, and adhesion were significantly higher on RGD containing peptide films.
Well-ordered protein assemblies on metallic substrates can be produced with the proper choice of peptide chain structure and terminal residues. Biological activity is a function of film composition and oligopeptide pendant structure.