Surface free energy and cell attachment onto ion-beam irradiated polymer surfaces

The paper reports evidence of the different cytocompatibility towards ion irradiated polymer surfaces. In particular, we studied the cell attachment, adhesion and spreading of normal human dermal fibroblast cells onto poly(hydroxymethylsiloxane) and poly(ethyleneterephthalate) surfaces modified by 50 keV Ar+ beams. The cell response is discussed in connection with the radiation-induced changes of the polymers surface chemical structure and related surface free energy, investigated by means of X-ray photoelectron spectroscopy and static contact angle measurements. The biological response is interpreted in terms of the different modification trends of the Surface Free Energy components, and its relationship to the protein adsorption processes from culture medium or to the direct cell-surface interaction in a protein-free saline solution. The results point towards a critical role of the electron-donor character of the surfaces, which seems able to trigger the optimal cell response to the employed polymeric surfaces.