Effects of surface-coupled polyethylene oxide on human macrophage adhesionand foreign body giant cell formation in vitro

Surface immobilized polyethylene oxide (PEG) has been shown to efficiently reduce protein adsorption and cellular adhesion, resulting in a biologicall y passive surface. To explore the in vitro effects of surface immobilized P EO on the human inflammatory cells, macrophages, and foreign body giant cel ls (FBGCs), we developed a diisocyanate-based method for coupling PEG to am ine-modified glass, a surface previously shown to enhance macrophage adhesi on and FBGC formation. Contact angle analysis and X-ray photoelectron spect roscopy confirmed the presence of PEG molecules bound to the surface and re vealed that PEG molecular weight significantly influenced the efficiency of PEO coupling. We used a 10-day human monocyte culture protocol to demonstr ate that the presence of surface coupled PEG molecules does not significant ly decrease initial monocyte density or monocyte-derived macrophage density after 3 days. However, PEG-coupled surfaces significantly reduced long-ter m monocyte-derived macrophage density and virtually eliminated interleukin- 4-induced FBGC formation observed at day 10. The cellular response to these PEG-coupled surfaces was related to the molecular weight of the PEG chains , which was varied between 200 Da and 18.5 kDa. These results suggest that an optimized PEG surface treatment may be effective in reducing inflammator y cell adhesion and possible degradation during the inflammatory response t o an implanted biomedical device. (C) 1999 John Wiley & Sons, Inc.