Titanium dioxide induced chemiluminescence of human polymorphonuclear leukocytes.

The ability of different titanium dioxides (TiO2) to induce production of reactive oxygen metabolites by human polymorphonuclear leukocytes was studied. Pure rutile or anatase preparations show only a weak chemiluminescent response. Surface-modified TiO2 causes a strong chemiluminescent response with a biphasic configuration resembling that of quartz. Sonication of the dust suspensions resulted in a strong enhancement of the chemiluminescent response, with each dust preparation showing approximately equal maximal activity. However, coated TiO2 still exhibited a different mode of cell activation. The chemiluminescence-inducing activity of the different TiO2 studied did not correlate with their hemolytic activity. As polyvinyl-pyridin-N-oxide (PVPNO) inhibits the chemiluminescence induced by coated TiO2 samples, it seems that both particle size and surface structure determine the mode and intensity of activation of human PMNL by TiO2. The results point out the need for in vivo testing and comparison of different TiO2 preparations.