Simulation On Nanopore And Charged Particle Translocation Based Finite Element Methods

Nanopore single molecule detection has been one of the research hotspot in recent years, it has been widely used in detection of various biological molecule and chemical analyte. The nanopore single molecular DNA sequencing technology was considered as the promising third generation sequencing technology by virtue of its advantages of fast detection and low cost, and it is being drawn more and more attentions in the research fields about advanced DNA sequencing.Nanopore single molecule detection is one of the technologies based on the Coulter counter method. Electrolyte solution is divided by a membrane with nanopore across which voltage is applied, and the ionic current through the nanopore will be detected. When a charged particle is driven to translocate the nanopore, the current curve will show a drop because of the blockage. The characteristics of the blockage current give the properties of the charged particle analyzed.The Finite Element Method (FEM) Analysis models about the nanopore and charged particle, which are based on Nernst-Planck model, were built with COMSOL Multiphysics?. The current change, electric potential distibution, ionic charges distribution and fluid flow and other factors in the nanopore without and without charged nanoparticle translocation in the nanopore were simulated. The results about the simulations of nanopore electric properties show that the I-V curves are linear in different concentration conditions; while the nanopore conductance becomes unlinear at low electrolyte concentration due to the notable electroosmotic effect in this condition.Because of the effect of volume occupancy of charged nanoparticle during the translocation , the translocating current will drop during this event. But meanwhile, the translocation current can be enhanced due to the electroosmotic effect in nanopore. The overall current change was a competitive result of the two effects mentioned above. At very low concentration, the overall current even show a rise compared with the original current due to the enhancing effect of electroosmsis. The size of nanopartecle also dramatically influence the translocating current profile. Generally, a short and thin particle influence trivial to the current change.The simulation results are in good agreement with the former experiments, and can give explanations to various effects. Finally, a modifying suggestion about further FEM simulation was proposed.