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

In this study, poly(D, L-lactide-co-glycolide) (PLGA) films were prepared by solvent casting method and the surfaces of the films were modified by application of oxygen plasma. A radio frequency (RF) generator working at 13.56 MHz was used to create plasma, and powers at different levels changing between 20 and 300 W were applied. The variations in chemistry, topography and surface free energy (SFE) of the films were investigated by electron spectroscopy for chemical analysis (ESCA), atomic force microscopy (AFM) and goniometer, respectively. The cell-material interactions of the modified samples were evaluated by cell culture tests using 3T3 fibroblast cell line. As the applied power of the RF generator was increased from 20 to 300 W, the surface oxygen content (examined by ESCA) first increased up to 100 W, and then decreased mostly because of crosslink formation by elimination of oxygen. Surface roughness (examined by AFM) and hydrophilicity (examined by water contact angle measurements) increased parallel to the applied power. SFE and the basic component of SFE also increased while the acidic component did not show a significant change with power according to the geometric mean approach. In vitro material-cell interaction studies showed that oxygen plasma modification enhanced the cell attachment and cell proliferation on PLGA samples. Copyright (C) 2010 John Wiley & Sons, Ltd.