Controlled wettability, same chemistry: biological activity of plasma-polymerized coatings

Plasma polymerization was used to produce novel nanometric coatings able to direct fibronectin adsorption and cell response. Using ethyl acrylate as a monomer, we obtain coatings whose chemical composition maintains some of the characteristic functionalities of the photo-initiated polymer, while the water contact angle increases monotonically with the duration of the plasma discharge. Enhanced surface mobility of the polymer chains due to a decrease of the thickness of the coating justifies this increase in wettability at lower treatment times. The coatings with higher surface mobility are shown to promote a more active conformation of the adsorbed protein, as proved by binding of the monoclonal antibodies HFN7.1 and mAb1937. Culture of MC3T3-E1 osteoblast-like cells onto the fibronectin-coated substrates further proves that the more mobile surfaces support better initial cell adhesion, even at low fibronectin surface density, as well as stronger cell-mediated fibronectin reorganization.