A novel electrochemical DNA biosensor fabricated with layer-by-layer covalent attachment of multiwalled carbon nanotubes and gold nanoparticles

A novel DNA biosensor has been fabricated for the detection of DNA hybridization based on layer-by-layer (LBL) covalent assembly of gold nanoparticles (GNPs) and multiwalled carbon nanotubes (MWCNTs). The stepwise LBL assembly process was characterized by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The hybridization events were monitored by differential pulse voltammetry (DPV) measurement of the intercalated doxorubicin, and the factors influencing the performance of the DNA hybridization was investigated in detail. ne signal was linearly changed with target DNA concentration increased from 0.5 to 0.01 nM, and had a detection limit of 7.5 pM (signal/noise ratio of 3). In addition, the DNA biosensor showed an excellent reproducibility and stability under the DNA-hybridization conditions.