title: The response effect of pheochromocytoma (PC12) cell lines to oxidized multi-walled carbon nanotubes (o-MWCMTs).
abstract: BACKGROUND
  The applications of oxidized carbon nanotubes (o-CNTs) have shown potentials in novel drug delivery including the brain which is usually a challenge. This underscores the importance to study its potential toxic effect in animals. Despite being a promising tool for biomedical applications little is known about the safety of drugs in treating brain diseases. The toxicity of oxidized multi-walled carbon nanotubes (o-MWCNTs) are of utmost concern and in most in-vitro studies conducted so far are on dendritic cell (DC) lines with limited data on PC12 cell lines.
  
  
  OBJECTIVE
  We focused on the effect of o-MWCNTs in PC12 cells in vitro: a common model cell for neurotoxicity.
  
  
  METHODS
  The pristine multi-walled carbon nanotubes (p-MWCNTs) were produced by the swirled floating catalytic chemical vapour deposition method (SFCCVD). The p-MWCNTs were then oxidized using purified H2SO4/HNO3 (3:1v/v) and 30% HNO3 acids to produce o-MWCNTs. The Brunauer-Emmett-Teller (BET), transmission electron microscopy (TEM), Scanning electron microscopy (SEM), thermogravimetric analyser (TGA) and Raman spectroscopy techniques were used to characterize the MWCNTs. The PC12 cells were cultured in RPMI medium containing concentrations of o-MWCNTs ranging from 50 to 200 µg/ml.
  
  
  RESULTS
  The o-MWCNTs demonstrated slight cytotoxicity at short time period to PC12 neuronal cells whilst at longer time period, no significant (p > 0.05) toxicity was observed due to cell recovery.
  
  
  CONCLUSIONS
  In conclusion, the o-MWCNTs did not affect the growth rate and viability of the PC12 cells due to lack of considerable toxicity in the cells during the observed time period but further investigations are required to determine cell recovery mechanism.
authors.affiliation: School of Chemical and Metallurgical Engineering, University of the Witwatersrand, Johannesburg, P/Bag 3, Wits 2050, South Africa.
authors.forename: C L
authors.initials: CL
authors.lastname: Phillips
authors.affiliation: School of Chemical and Metallurgical Engineering, University of the Witwatersrand, Johannesburg, P/Bag 3, Wits 2050, South Africa.
authors.forename: C S
authors.initials: CS
authors.lastname: Yah
authors.affiliation: School of Chemical and Metallurgical Engineering, University of the Witwatersrand, Johannesburg, P/Bag 3, Wits 2050, South Africa.
authors.forename: S E
authors.initials: SE
authors.lastname: Iyuke
authors.affiliation: Department of Pharmacy and Pharmacology, School of Therapeutic Sciences, University of the Witwatersrand, 7 York Road, Parktown, 2193 Johannesburg, South Africa.
authors.forename: V
authors.initials: V
authors.lastname: Pillay
authors.affiliation: School of Molecular & Cell Biology, University of the Witwatersrand, Johannesburg, P/Bag 3, Wits 2050, South Africa.
authors.forename: K
authors.initials: K
authors.lastname: Rumbold
authors.affiliation: Department of Pharmacy and Pharmacology, School of Therapeutic Sciences, University of the Witwatersrand, 7 York Road, Parktown, 2193 Johannesburg, South Africa.
authors.forename: Y
authors.initials: Y
authors.lastname: Choonara
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002460:Cell Line / Q000187:drug effects*; D046529:Microscopy, Electron, Transmission; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000633:toxicity* / Q000648:ultrastructure; D016501:Neurites / Q000187:drug effects / Q000378:metabolism; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D010084:Oxidation-Reduction; D051381:Rats
chemical_list: D037742:Nanotubes, Carbon
keywords: Oxidized carbon nanotubes; PC12; cellular response; toxicity