Nanosensor Chips for the Single-Molecule Sequencing of DNA and RNA
Steve Soper,
Foundation Distinguished Professor; Director, Center of BioModular Multi-scale System for Precision Medicine, Adjunct Professor, Ulsan National Institute of Science & Technology,
The University of Kansas
We are generating a single-molecule DNA/RNA sequencing platform that can
acquire sequencing information with high accuracy (>99%) at
unprecedented throughputs (106 nt/s). The technology employs a fluidic
chip populated with nanosensors that read the identity of individual
mononucleotides from their characteristic flight-time through a
2-dimensional (2D) nanochannel (~50 nm in width and depth; >10 µm in
length) and their current transient amplitudes. The nanosensors are
fabricated in a thermoplastic via nanoimprint lithography (NIL). The
mononucleotides are generated from an intact DNA fragment using a highly
processive exonuclease, which is covalently anchored to a plastic
support (500 nm in diameter) contained within a bioreactor that
sequentially feeds mononucleotides into a 2D nanochannel. The identity
of the mononucleotides is deduced from a molecular-dependent flight-time
through the 2D nanochannel that is related to the electrophoretic
mobility of that molecule. The flight time is read in a label-less
fashion by measuring current transients (i.e., resistive pulse sensing)
induced by a single mononucleotide when it travels through a
constriction possessing molecular dimensions (<10 nm in diameter) and
poised at the input/output ends of the flight tube. In this
presentation, our efforts in building these nanosensors using NIL in
thermoplastics will be discussed. We will also talk about the detection
of single molecules using NIL-produced nanopores. Also, surface
modifications of plastics for the immobilization of biologics, such as
exonucleases, will be discussed and their enzymatic performance when
surface immobilized. Finally, information on the manipulation of single
DNA molecules using nanofluidic circuits that uses nano-scale features
to shape electric fields will be presented.
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