23447468

PMC4039041

Eosinophil peroxidase (EPO) is one of the major oxidant-producing enzymes during inflammatory states in the human lung. The degradation of single-walled carbon nanotubes (SWCNTs) upon incubation with human EPO and H₂O₂ is reported. Biodegradation of SWCNTs is higher in the presence of NaBr, but neither EPO alone nor H₂O₂ alone caused the degradation of nanotubes. Molecular modeling reveals two binding sites for SWCNTs on EPO, one located at the proximal side (same side as the catalytic site) and the other on the distal side of EPO. The oxidized groups on SWCNTs in both cases are stabilized by electrostatic interactions with positively charged residues. Biodegradation of SWCNTs can also be executed in an ex vivo culture system using primary murine eosinophils stimulated to undergo degranulation. Biodegradation is proven by a range of methods including transmission electron microscopy, UV-visible-NIR spectroscopy, Raman spectroscopy, and confocal Raman imaging. Thus, human EPO (in vitro) and ex vivo activated eosinophils mediate biodegradation of SWCNTs: an observation that is relevant to pulmonary responses to these materials.

CDC Public Access

3927ZHF/PHS HHS/United States
3927ZJQP/PHS HHS/United States
HL094488/HL/NHLBI NIH HHS/United States
HL70755/HL/NHLBI NIH HHS/United States
OH008282/OH/NIOSH CDC HHS/United States
R01 ES019304/ES/NIEHS NIH HHS/United States
R01 HL070755/HL/NHLBI NIH HHS/United States
R01 HL094488/HL/NHLBI NIH HHS/United States
R01ES019304/ES/NIEHS NIH HHS/United States
U19 AI068021/AI/NIAID NIH HHS/United States
U19AI068021/AI/NIAID NIH HHS/United States