A Single-Molecule Label-Free Identification of Single-Nucleotide Colorectal-Cancer-DNA Polymorphism Using Impedance Spectroscopy of Self-Redox-Active Decorated Carbon Nanotubes

A novel label-free impedance assay which is based on self-redox active carbon nanotube arrays decorated by nanocyclic organometallic complex monolayer is offered to discriminate single-nucleotide polymorphism of colorectal-tumor genome. The assay is based on the following effects. A mass transfer for the multiwalled carbon nanotubes (MWCNTs) is testified by a Cole–Cole plot with Warburg impedance in dielectric spectra. Charging K(K')-point of graphene Brillouin zone is associated with the mass transfer for MWCNTs that leads to arising of charged MWCNT-end states. Plasma oscillations of charge carriers shield electric field of charged electrodes. Complementary hybridization of target deoxyribonucleic acid (DNA) with probe DNA on the MWCNT surface facilitates the penetration of single-stranded target DNA in the nanopores. Dielectric-band appearance and shielding effects testify the duplex formation.