Master of Science (MS)
Recently, there have been reports on biological and solid-state nanopores that identify single biopolymers or their constituent monomers by analyzing changes in ionic current blockades when they block the flux of buffer ions while travelling through the nanopores. Nevertheless, there have been several limitations in their application, especially as DNA detectors; Poor confinement of the DNA strand within the nanopore (~0.1 % of a 10 kilobase (kb) DNA), poor signal sensitivity and random motion experienced by the DNA in solution that results in a large amount of noise in the signal. These have led to the development of nanochannel-based devices, which can directly address the aforementioned challenges. Nanochannels have widths comparable to nanopores but with longer lengths. As molecules travel through nanochannels, they undergo confinement, hydrophobic and van der Waals interactions with the walls of the channel generating some interesting physics, such as the elongation of DNA molecules. The small scale analyses offer high throughput with interesting attributes not accessible at the micro-scale. Presently, an expanding research area involves the integration of nanochannels with nanogap electrodes to provide new transduction modalities for single molecules traveling through nanochannels. In these detectors, the electrical behavior (field effect, impedance, capacitance, resistance, conductance, etc.) of biomolecules are observed. These have become powerful tools for bio-sensing, single molecule manipulation and design of high throughput systems, for example as systems for DNA sequencing. This work focuses on developing a novel technique for the fabrication of mixed-scale systems (nm to mm) in quartz used for the molecular-scale sensing of single-molecules (DNAs, RNAs, peptides and proteins). These systems consist of both microchannels and nanochannels (10-100 nm). Results on the fabrication of such systems will be reported. I will also discuss our ultimate goal; to develop a platform for the rapid and efficient sequencing of biopolymers by measuring flight-times of monomer units clipped from a single polymer digested with an enzyme. The flight times will be transduced using a non-labeling electrical approach via conductivity in a detection volume defined by nano-scale electrodes (5-10 nm). Theoretical computations performed to describe the variation of the Signal-to-Noise with the nano-electrode area and nano-gap size have provided promising results.
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Uba, Franklin Ifeanyichukwu, "Transport Properties of Nanometer-sized Assemblies through Nanofluidic Channels with Single Entity Electrical Detection" (2011). LSU Master's Theses. 623.