Influence of Biofluids Rheological Behavior on Electroosmotic Flow and Ionic Current Rectification in Conical Nanopores

Flow through nanopores has received a great deal of attention during the past decade due to its versatile areas of application in biology and engineering. The asymmetrical geometry of conical nanopores has made these devices advantageous in rectification of ionic current for counting and detection of biofluidic entities such as proteins and DNAs. Protein solutions exhibit non-Newtonian rheological behavior which mathematically alludes to a nonlinear relation between shear stress and shear rate. In this study, the electroosmotic flow (EOF) of non-Newtonian solutions through a conical nanopore with a constant charge density on the wall is investigated numerically. Using the assumption of continuity, the ionic transport in the EO flow is modeled by combining the Poisson, Nernst–Plank, and Navier–Stokes equations for potential field, ionic concentration, and velocity distributions, respectively. The biofluid is assumed to behave as a non-Newtonian power-law fluid with constant physical properties. For both overlapping and nonoverlapping electric double layers, the effects of biofluid rheological behavior, surface charge density, applied voltage, and the ratio of the pore radius to the Debye length on the ionic current rectification and the EOF are studied.