Microchamber device for studying phagocytosis of ultra-high molecular weight polyethylene particles by human monocyte-derived macrophages

It is well established in the literature that polyethylene wear particles are involved in loosening of joint prostheses. To investigate the phagocytosis of ultra-high molecular weight polyethylene particles by human monocyte-derived macrophages and the secretion of inflammatory cytokines, a microchamber was fabricated with a height of 200 mu m and diameter of 15 mm. The chamber had inlet and outlet ports for continuous administration of culture medium with polyethylene particles. These configurations enabled the polyethylene particles to pass near the macrophages and enabled quantitative and time-dependent assessments. Administration of culture medium with no polyethylene particles was used as a negative control, for which the secretion of TNF-alpha was not detected. With increasing administration of the polyethylene particles, the secretion of TNF-alpha gradually increased. With increasing administration of the lipopolysaccharide as a positive control, the secretion of TNF-alpha increased, reached a peak, and then gradually decreased. Furthermore, TNF-alpha secretion was influenced by polyethylene particle size. Particles with mean diameters of 0.77 and 1.10 mu m brought about greater TNF-alpha production than those with a mean diameter of 1.99 mu m. These results suggest that the microchamber device could be used to elucidate the differences in TNF-alpha secretion resulting from various sizes of wear particles.