Adsorption and Electrooxidation of Nucleic Acids at Glassy Carbon Electrodes Modified with Multiwalled Carbon Nanotubes Dispersed In Polylysine

We report the advantages of the adsorption and electrooxidation of oligonucleotides and calf-thymus double stranded DNA (dsDNA) at glassy carbon electrodes (GCE) modified with a dispersion of multiwalled carbon nanotubes (MWCNT) in poly-L-lysine (Plys) (GCE/MWCNT-Plys). Important enhancement in the guanine oxidation signal was obtained by adsorptive stripping voltammetry (AdSV) due to a most favorable interaction between the negatively charged DNAs and the positively charged Plys that support the MWCNT. The layer of oligo(dG)11 immobilized at GCE/MWCNT-Plys was successfully used for the selective detection of the hybridization event using oligo(dG)11/oligo(dC)11 as model.