Electrochemical biosensors based on carbon nanotubes

Carbon nanotubes, especially SWNTs, with their fascinating electrical properties, dimensional proximity to biomacromolecules (e.g., DNA of 1 nm in size), and high sensitivity to surrounding environments, are ideal components in biosensors not only as electrodes for signal transmission but also as detectors for sensing biomolecules and biospecies. In terms of configuration and detection mechanism, biosensors based on carbon nanotubes may be divided into two categories electrochemical sensors and field effect transistor (FET) sensors. Since a number of recent reviews on the former have been published,6,62,63 our focus here is mostly on FET sensors. 

Timur, S., Anik, U., Odaci, D., and Gorton, L. (2007) Development of a microbial biosensor based on carbon nanotube (CNT) modified electrodes. Electrochem. Commun., 9 (7), 1810-1815. 

G. Cheng, J. Zhao, Y. Tu, P. He, and Y. Fang, A sensitive DNA electrochemical biosensor based on magnetite with a glassy carbon electrode modified by multi-walled carbon nanotubes in polypyrrole. Anal. Chim. Acta 533, 11-16 (2005). 

Manso, J., Mena, M.L., Yanez-Sedeno, P., Pingarron, J.M. (2007) Electrochemical biosensors based on colloidal gold-carbon nanotubes-Teflon composite electrodes. J. Electroanal. Chem., 603, 1-7... 

In the last 5 years, our attention has been paid to the development of novel electrochemical DNA biosensors based on carbon-based transducers as substrates for immobilization of DNA. Among others, following four electrodes exhibited the best properties for these purposes GCE (supplied by Metrohm, Herisau, Switzerland), microcrystalline natural graphite-polystyrene composite film-modified electrode (CFE), SPCE (supplied by Food Research Institute, Bratislava, Slovakia), and SPCE modified with single-walled carbon nanotubes (SWCNTs). 

Z. Chang, H. Fan, K. Zhao, M. Chen, P. He, and Y. Fang. Electrochemical DNA biosensors based on Palladium nanoparticles combined with carbon nanotubes. Electroanalysis 20,131-136 (2008). 

Cesarino, I., Moraes, F. C., and Machado, S. A. S. (2011). A biosensor based on polyaniline-carbon nanotube core-shell for electrochemical detection of pesticides, Eiectroanalysis, 23, pp. 2586-2593. 

Liu, G., Lin, Y. Amperometric glucose biosensor based on self-assembling glucose oxidase on carbon nanotubes. Electrochem. Commun. 8(2), 251-256 (2006)... 

Kalcher K, Svancara I, Buzuk M, Vytras K, Walcarius A (2009) Electrochemical sensors and biosensors based on heterogeneous carbon materials. Monatsh Chem 140 861—889 Kauffman DR, Star A (2010) Graphene versus carbon nanotubes for chemictil sensor and fuel cell applications. Analyst... 

Using a glass carbon electrode (GCE) modified with MWCNTs, Cai et al. ° observed an enhanced sensitivity for electrochemical DNA biosensor based on CNTs. Figure 6.22 schematically shows the steps for constructing the nanotube-DNA biosensor. To start, carboxylic acid functionalized MWCNTs (COOH-MWCNTs) were dropped on a GCE electrode, single-strand DNA oligonucleotides (ss-DNAs) were then covalently bonded onto the COOH-MWCNTs via amide formation. The hybridization reaction on the electrode was monitored by differential pulse voltammetry (DPV) using an electroactive daunomycin intercalator as the indicator. 

Cesarino, 1., Moraes, F.C., Lanza, M.R.V. and Machado, S.A.S. (2012) Electrochemical detection of carbamate pesticides in fruit and vegetables with a biosensor based on acetylcholinesterase immobilised on a composite of polyaniline-carbon nanotubes. 

A label-free electrochemical DNA biosensor based on 4,4 -diaminoazobenzene (4,4 -DAAB) and multiwalled carbon nanotube (MWNT)-modified GCE for short DNA sequences related to HBV hybridization detection was presented by Li et al. [92]. DPV was used to investigate hybridization event. The decrease in the peak ciurent of 4,4 -DAAB was observed on hybridization of probe with the target. This electrochemical approach was sequence specific as indicated by the control experiments, in which no peak eurrent change was observed when a non complementary DNA sequence was used. Numerous factors affecting the target hybridization were optimized to maximize the sensitivity. Under optimal conditions, this sensor showed a good calibration range between 7.94 xlO M and 1.58 xlO M, with HBV DNA sequence deteetion limit of 1.1 xlO M. 

Zhang, Y., K. Zhang, and H. Ma, Electrochemical DNA biosensor based on silver nanoparticles/poly(3-(3-pyridyl) aciylic acid)/carbon nanotubes modified electrode. 

Zhang X, Jiao K, Liu S, Hu Y (2009) Readily reusable electrochemical DNA hybridization biosensor based on the interaction of DNA with single-walled carbon nanotubes. Anal Chem 81 6006-6012... 

Chang, Z., Fan, H., Zhao, K., Chen, M., He, P. and Fang, Y. (2007) Electrochemical DNA biosensors based on palladium nanopartides combined with carbon nanotubes. ElectroarMlysis,... 

---