Ion beam induced nanometric structure and oligopeptide adsorption on patterned polymer surfaces

The adsorption process of the H–Arg–Gly–Asp–OH oligopeptide (RGD sequence) onto surfaces of poly(ethyleneterephtalate) and poly(caprolactone) patterned by 50 keV Ar+ ion beams is discussed. The irradiation through masks patterned with micrometric features was employed to create grooves and/or pits of nanometric depth. Both XPS and Imaging time-of-flight secondary-ion mass spectrometry (ToF-SIMS) measurements showed that incubation of the polymer samples with RGD solutions produces a preferential adsorption on the ion-irradiated areas of the PCL surfaces, while only a negligible adsorption is obtained onto PET. The adsorption behaviour of the RGD is found to correlate with the surface nanostructuring induced by the ion irradiation.