The Body's Response to Deliberate Implants: Phagocytic Cell Responses to Large SubstrataVs.Small Particles

Abstract It is important to characterize possible inflammatory responses to small particles, and to separate clearly these effects from responses to larger objects nearby. This research used a chemiluminescent assay, scanning electron micrographs, and energy dispersive X-ray spectra to monitor inflammation-related reactive oxygen intermediate (ROI) production and morphological alterations of human monocyte-derived macrophages interacting with the walls of apolar and polar polystyrene cuvettes, in the absence and presence of small particles of surface-characterized Teflon™, polyethylene, Co-Cr-Mo alloy, titanium and alumina. The two types of polystyrene substrata represent the “bacterial” (as produced) and “tissue culture” (gas-plasma-treated [GPT]) materials widely used in biological testing and tissue culture. Monocyte-derived macrophage spreading during contact with the higher-surface-energy, more polar substratum suppressed “oxidative bursts” to lower levels than expressed from rounded cells in contact with the lower-energy, apolar substratum. Particulate matter engulfed by both rounded and spread cells did not significantly enhance ROI production beyond levels observed for no-particle controls during the one-hour exposure time. Biocompatibility of some implants might be related to cell-spreading-induced suppression of ROI production, improving the tissue integration of GPT implants.