Characterization of DNA translocation through a silicon based nanopore
The direct characterization, detection, and identification of single nucleic acid molecules can revolutionize genomics, expression analysis, and many areas of biological sciences, such as nano-medicine and nano-system biology. A nanopore fabricated using micro and nano-fabrication technique is a viable sensor for such single molecule studies. The idea is essentially a counter-counter based approach, in which the electric detection is achieved by blocking of the ionic current in the system when the species of interest passes through the single pore. Here we report the fabrication and processes characterization of silicon-based nanopore channels using e-beam lithography and (1) TEM based and (2) FESEM based processes. Subsequently, DNA measurements were performed with the nanopore as a function of potassium chloride concentrations and applied electrophoretic biases. We surprisingly observed both upwards and downwards pulses upon the translocation of DNA through the nanopore channels with varying bulk solution ionic concentration. At low ionic concentrations, the DNA resulted in increase in current whereas with higher ionic concentrations, the DNA resulted in a decrease in current. The experimental results will be presented and the explanations will be provided for the observed phenomena.
Bashir, Purdue University.
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