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Biodegradation of Single‐Walled Carbon Nanotubes by Eosinophil Peroxidase
Author(s) -
Andón Fernando T.,
Kapralov Alexandr A.,
Yanamala Naveena,
Feng Weihong,
Baygan Arjang,
Chambers Benedict J.,
Hultenby Kjell,
Ye Fei,
Toprak Muhammet S.,
Brandner Birgit D.,
Fornara Andrea,
KleinSeetharaman Judith,
Kotchey Gregg P.,
Star Alexander,
Shvedova Anna A.,
Fadeel Bengt,
Kagan Valerian E.
Publication year - 2013
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201202508
Subject(s) - biodegradation , eosinophil peroxidase , carbon nanotube , raman spectroscopy , ex vivo , materials science , chemistry , peroxidase , chemical engineering , biophysics , nanotechnology , organic chemistry , enzyme , in vitro , biochemistry , biology , physics , optics , engineering
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 H 2 O 2 is reported. Biodegradation of SWCNTs is higher in the presence of NaBr, but neither EPO alone nor H 2 O 2 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.