Multiwalled carbon nanotubes covalent attachment

An other interesting strategy is the modification of the surface of the electrodes with multiwalled carbon nanotubes (MWNTs) or single-walled carbon nanotubes (SWNTs) [13,32]. The MWNTs are grown on the electrodes covered with a nickel catalyst film by plasma-enhanced chemical vapour deposition and encapsulated in Si02 dielectrics with only the end exposed at the surface to form an inlaid nanoelectrode array [13]. In the other case, commercial SWNTs are deposited on SPE surface by evaporation [32], The carbon nanotubes are functionalised with ssDNA probes by covalent attachment. This kind of modification shows a very efficient hybridisation and, moreover, the carbon nanotubes improve the analytical signal. 

The other immobilization methods include carbon nanotubes and nanoparticles. PolyCglycidyl methacrylate)-grafted multiwalled carbon nanotubes (MWNT) were covalently attached to A-butyl imidazolium bromide. An indium tin oxide (ETO) electrode coated with such MWNT-IL successfully immobilized tyrosinase and showed sensing response toward phenol at the range of 0.01-0.08 mM at ambient pH and temperature [60]. Similarly, glassy carbon (GC) electrode was coated with... 

Intercalated doxorubicin has been also used as an electrochemical label in the detection of DNA hybridization events in a genosensor built by layer-by-layer covalent attachment of multiwalled carbon nanotubes and Au-NPs [46]. The oxidation peak current obtained by differential pulse voltammetry showed a linear relationship with the logarithm of the target DNA concentration in the range 5.0 x 10 to 1.0 x 10 M, with a detection limit of 6.2 pM. 

Khezrian S, Salimi A, Teymourian H, Hallaj R (2013) Label-free electrochemical IgE aptasensor based on covalent attachment of aptamer onto multiwalled carbon nanotubes/ionic liquid/chitosan nanocomposite modified electrode. Biosens Bioelectron 43 218-225... 

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