(220h) Field Effect Control of DNA Nanoparticle Electrokinetic Translocation Through a Nanopore

A DNA nanoparticle is electrophoretically driven through a single nanopore connecting two fluid reservoirs on either side under an axial electric field externally imposed. The ionic current is simultaneously altered and measured during the nanoparticle electrokinetic translocation process. Based on the current response to the presence of DNA molecules within a nanopore, one hopes to characterize the nanoparticle such as the determination of each nucleotide base in the DNA nanoparticle. One of the most challenging issues in the nanopore-based DNA sequencing technique is that DNA molecules translocate through the nanopore too fast for detection. Therefore, slowing down the nanoparticle electrokinetic translocation through the nanopore to obtain a detectable current change signal is required. We numerically investigated the field effect control of DNA molecules translocation through a nanopore by a field effect transistor (FET) using a continuum model, composed of the coupled Poisson-Nernst-Planck equations for the ionic mass transport and the Navier-Stokes equations for the hydrodynamic field. The FET contains a gate electrode fabricated on the outer surface of the dielectric nanopore. A potential applied to the gate electrode affects the surface potential on the nanopore’s inner wall, which in turn affects the net charge of the ionic electrolyte solution and thus the electroosmotic flow (EOF) inside the nanopore. The particle translocation will be retarded when the induced EOF is opposite to the particle electrophoretic motion. The FET control of the DNA translocation in a nanopore is investigated as a function of the ratio of the particle size to the Debye length, the ratio of the surface charged density of the nanopore to that of the particle, and the dielectric property of the dielectric transistor. Two effects arising from the field effect control, namely the EOF and the particle-nanopore electrostatic interaction, can effectively regulate the DNA translocation through a nanopore.