TY  - JOUR
AU  - Allen, B..
AU  - Kotchey, G.
AU  - Chen, Y.
AU  - Yanamala, N.
AU  - Klein-Seetharaman, J.
AU  - Kagan, V.
AU  - Star, A.
TI  - Mechanistic Investigations of Horseradish Peroxidase-Catalyzed Degradation of Single-Walled Carbon Nanotubes
JO  - Journal of the American Chemical Society
VL  - 131
SN  - 0002-7863
CY  - Washington, DC
PB  - American Chemical Society
M1  - PreJuSER-7756
SP  - 17194 - 17205
PY  - 2009
N1  - This work was supported by AFOSR, Grant no. FA 9550-09-1-0478; NIOSH OH008282 and the 7th Framework Programme of the European Commission (NANOMMUNE).
AB  - Single-walled carbon nanotubes (SWNTs) have been investigated for a variety of applications including composite materials, electronics, and drug delivery. However, these applications may be compromised depending on the negative effects of SWNTs to living systems. While reports of toxicity induced by SWNTs vary, means to alleviate or quell these effects are in small abundance. We have reported recently the degradation of carboxylated SWNTs through enzymatic catalysis with horseradish peroxidase (HRP). In this full Article, we investigated the degradation of both carboxylated and pristine SWNTs with HRP and compared these results with chemical degradation by hemin and FeCl(3). The interaction between pristine and carboxylated SWNTs with HRP was further studied by computer modeling, and the products of the enzymatic degradation were identified. By examining these factors with both pristine and carboxylated SWNTs through a variety of techniques including atomic force microscopy (AFM), transmission electron microscopy (TEM), Raman spectroscopy, ultraviolet-visible-near-infrared (UV-vis-NIR) spectroscopy, gas chromatography-mass spectrometry (GC-MS), high-performance liquid chromatography (HPLC), and liquid chromatography-mass spectrometry (LC-MS), degradation pathways were elucidated. It was observed that pristine SWNTs demonstrate no degradation with HRP incubation but display significant degradation when incubated with either hemin or FeCl(3). Such data signify a heterolytic cleavage of H(2)O(2) with HRP as pristine nanotubes do not degrade, whereas Fenton catalysis results in the homolytic cleavage of H(2)O(2) producing free radicals that oxidize pristine SWNTs. Product analysis shows complete degradation produces CO(2) gas. Conversely, incomplete degradation results in the formation of different oxidized aromatic hydrocarbons.
KW  - Biocatalysis
KW  - Horseradish Peroxidase: metabolism
KW  - Microscopy, Atomic Force
KW  - Microscopy, Electron, Transmission
KW  - Nanotubes, Carbon
KW  - Spectrum Analysis: methods
KW  - Nanotubes, Carbon (NLM Chemicals)
KW  - Horseradish Peroxidase (NLM Chemicals)
KW  - J (WoSType)
LB  - PUB:(DE-HGF)16
C6  - pmid:19891488
UR  - <Go to ISI:>//WOS:000272207300042
DO  - DOI:10.1021/ja9083623
UR  - https://juser.fz-juelich.de/record/7756
ER  -