Nanographite impurities in carbon nanotubes: their influence on the oxidation of insulin, nitric oxide, and extracellular thiols.
There has been growing interest in the use of modified-carbon-nanotube electrodes in applications such as the electrochemical detection of biologically significant compounds, owing to their apparent "electrocatalytic" properties and ability to enhance oxidative signals. In spite of their salient properties, little work has been done to further examine the reasons for these reported characteristics. In this report, we present clear evidence that the presence of nanographite impurities within carbon nanotubes (CNTs) is responsible for providing the previously reported enhanced electrochemical response. We have demonstrated this effect on homocysteine, N-acetyl-L-cysteine, nitric oxide, and insulin, which are important biological agents in the body. Moreover, we also showed that the influence of nanographite impurities on the electrochemistry of carbon nanotubes is prevalent among a variety of CNTs, such as single-walled CNTs, double-walled CNTs, and few-walled CNTs. Our findings will have a profound influence upon the biomedical applications of CNTs.
Division of Chmistry & Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore.
Elaine Lay Khim
EL
Chng
Martin
M
Pumera
D000111:Acetylcysteine / Q000737:chemistry; D004563:Electrochemistry; D007328:Insulin / Q000737:chemistry*; D037742:Nanotubes, Carbon / Q000737:chemistry*; D009569:Nitric Oxide / Q000737:chemistry*; D010084:Oxidation-Reduction; D013438:Sulfhydryl Compounds / Q000737:chemistry*
D007328:Insulin; D037742:Nanotubes, Carbon; D013438:Sulfhydryl Compounds; D009569:Nitric Oxide; D000111:Acetylcysteine