Fig. 10

Illustration of proposed mechanisms underlying the acute phase immune response to ZnO-coated MWCNTs (Z-MWCNTs) in human THP-1 monocytes in vitro and after delivery to the lungs of mice in vivo by oropharyngeal aspiration. Uncoated MWCNTs (U-MWCNTs) are subjected to atomic layer deposition (ALD) coating with ZnO to yield Z-MWCNTs. Sonication results in breakage of Z-MWCNTs and the ZnO coating also undergoes partial dissolution to release Zn⁺² ions in aqueous media. Unlike U-MWCNTs, Z-MWCNTs are not taken up by phagocytic monocytes or macrophages in vitro or in vivo. Z-MWCNTs cause epithelial cell growth arrest and increases in CXCL10, a monocyte chemoattractant, as well as increases in IL-6 that mediates systemic acute phase responses