For the first time, a new platform based on electrochemical growth of Au nanoparticles on aligned multi-walled
carbon nanotubes (A-MWCNT) was developed for sensitive lable-free
DNA detection of the TP53 gene mutation, one of the most popular genes in
cancer research. Electrochemical impedance spectroscopy (EIS) was used to monitor the sequence-specific
DNA hybridization events related to TP53 gene. Compared to the bare Ta or MWCNT/Ta
electrodes, the synergistic interactions of vertically aligned MWCNT array and
gold nanoparticles at modified
electrode could improve the density of the
probe DNA attachment and resulting the sensitivity of the
DNA sensor greatly. Using EIS, over the extended
DNA concentration range, the change of charge transfer resistance was found to have a linear relationship in respect to the logarithm of the complementary
oligonucleotides sequence concentrations in the wide range of 1.0×10(-15)-1.0×10(-7)M, with a detection limit of 1.0×10(-17)M (S/N=3). The prepared sensor also showed good stability (14 days), reproducibility (RSD=2.1%) and could be conveniently regenerated via dehybridization in hot water. The significant improvement in sensitivity illustrates that combining
gold nanoparticles with the on-site fabricated aligned MWCNT array represents a promising platform for achieving sensitive biosensor for fast mutation screening related to most human
cancer types.