Effect of oxygen plasma on surface properties and biocompatibility of PLGA films

Chemical structure, roughness, hydrophilicity, distribution of charged groups, etc. are the examples of factors that affect the cell attachment and cell proliferation in tissue engineering applications. Plasma glow discharge is one technique which is used to modify the surfaces without affecting the bulk properties. In this study, poly(D, L-lactide-co-glycolide) (PLGA) films were prepared by solvent casting in chemistry, topography and surface free energy (SFE) with oxygen plasma treatment were investigated by electron spectroscopy for chemical analysis (ESCA), atomic force microscopy (AFM) and goniometer, respectively. The cell-material interactions of the samples were evaluated by cell culture tests using 3T3 fibroblast cell line. As the applied power of the RF generator was increased from 20 watts to 300 watts, the surface oxygen content (examined by ESCA) first increased up to 100 watts, and then decreased mostly because of crosslink formation by elimination of oxygen. Surface roughness was examined by AFM and hydrophilicity was examined by water contact angle measurement. SFE values of PLGA films increased in agreement with the applied power according to harmonic mean, geometric mean and acid base approaches. In vitro material-cell interaction studies showed that, oxygen plasma modification enhanced cell attachment and cell proliferation on PLGA films.