HUMAN MONOCYTE MACROPHAGE ADHESION, MACROPHAGE MOTILITY, AND IL-4-INDUCED FOREIGN-BODY GIANT-CELL FORMATION ON SILANE-MODIFIED SURFACES IN-VITRO/

A cytokine-based, in vitro model of foreign body giant cell (FBGC) for mation was utilized to examine the effect of biomaterial surface chemi stry on the adhesion, motility, and fusion of monocytes and macrophage s. Human monocytes were cultured for 10 days on 14 different silane-mo dified glass surfaces, during which time the cells assumed the macroph age phenotype. The adhesion of monocytes and macrophages during the cu lture period decreased by an average of similar to 50%, with the major ity of cell loss observed during days 1-3. Most important, the adhesio n of monocytes and macrophages was surface independent except for two surfaces containing terminal methyl groups, which decreased adhesion l evels. Interleukin-4 (IL-4) and granulocyte-macrophage colony-stimulat ing factor (GMCSF) were added to the medium to induce FBGC formation a nd enhance macrophage adhesion, respectively. Surprisingly, GM-CSF dec reased long-term monocyte/macrophage adhesion. IL-4-induced FBGC densi ty was strongly influenced by the surface carbon content, as determine d by X-ray photoelectron spectroscopy (XPS). In contrast, contact angl e and surface energy displayed no correlation with FBGC formation. The motility of adherent macrophages, as measured by time-lapse confocal microscopy, was not affected significantly by differences in surface c hemistry or the addition of cytokines. The surface dependence of FBGC formation is hypothesized to be the result of varying levels of silane -derived surface carbon. (C) 1998 John Wiley & Sons, Inc.