2 research outputs found
Selectively Sized Graphene-Based Nanopores for in Situ Single Molecule Sensing
The use of nanopore biosensors is
set to be extremely important in developing precise single molecule
detectors and providing highly sensitive advanced analysis of biological
molecules. The precise tailoring of nanopore size is a significant
step toward achieving this, as it would allow for a nanopore to be
tuned to a corresponding analyte. The work presented here details
a methodology for selectively opening nanopores in real-time. The
tunable nanopores on a quartz nanopipette platform are fabricated
using the electroetching of a graphene-based membrane constructed
from individual graphene nanoflakes (ø ∼30 nm). The device
design allows for in situ opening of the graphene membrane, from fully
closed to fully opened (ø ∼25 nm), a feature that has
yet to be reported in the literature. The translocation of DNA is
studied as the pore size is varied, allowing for subfeatures of DNA
to be detected with slower DNA translocations at smaller pore sizes,
and the ability to observe trends as the pore is opened. This approach
opens the door to creating a device that can be target to detect specific
analytes
Single Molecule Trapping and Sensing Using Dual Nanopores Separated by a Zeptoliter Nanobridge
There
is a growing realization, especially within the diagnostic
and therapeutic community, that the amount of information enclosed
in a single molecule can not only enable a better understanding of
biophysical pathways, but also offer exceptional value for early stage
biomarker detection of disease onset. To this end, numerous single
molecule strategies have been proposed, and in terms of label-free
routes, nanopore sensing has emerged as one of the most promising
methods. However, being able to finely control molecular transport
in terms of transport rate, resolution, and signal-to-noise ratio
(SNR) is essential to take full advantage of the technology benefits.
Here we propose a novel solution to these challenges based on a method
that allows biomolecules to be individually confined into a zeptoliter
nanoscale droplet bridging two adjacent nanopores (nanobridge) with
a 20 nm separation. Molecules that undergo confinement in the nanobridge
are slowed down by up to 3 orders of magnitude compared to conventional
nanopores. This leads to a dramatic improvement in the SNR, resolution,
sensitivity, and limit of detection. The strategy implemented is universal
and as highlighted in this manuscript can be used for the detection
of dsDNA, RNA, ssDNA, and proteins