Recent advances in cost-effective, ultra-rapid, and efficient
DNA
sequencing are in the saddle of the advancement of the personalization
of medicines for understanding and early-stage detection of several
killer diseases. Paying attention to a timely need for the development
of solid-state nanodevices for rapid and controlled identification
of DNA nucleotides, in this report, we theoretically explored the
potential of labeling techniques in the sequencing of DNA nucleotides
through solid-state graphene nanogap electrodes using the quantum
tunneling current approach. Our study boasts the idea that labeling
of DNA nucleotides can solve major hurdles of DNA sequencing, such
as improving the signal-to-noise ratio, slowing down translocation
velocity, and controlling orientational variations. Employing the
first-principle density functional theory study, we identify unique
interaction energy values for each labeled nucleotide having remarkable
differences in the range of 0.10–0.74 eV. The zero-bias transmission
spectra of the proposed setup suggest that the detection of the nucleotides
is possible by applying very low gate voltages. Moreover, the labeling
of nucleotides amplifies the conductance sensitivity considerably. I–V characteristics suggest that
electrical recognition of each labeled nucleotide can be carried out
at both lower (0.3 V) and higher (0.8 V) bias voltages with single-molecule
resolution, although the maximum current sensitivity is observed at
a higher bias voltage. The proposed sequencing device possesses high
sensitivity and selectivity characteristics that are crucial for experimental
purposes. We find that our results are rich compared to unlabeled
nucleotides-based graphene nanopore/nanogap devices. Hence, the study
will certainly motivate the experimentalists toward the application
of a labeled DNA nucleotide system for ultra-rapid DNA sequencing
by using the tunneling current approach.