Fluid dynamics and electrical detection of λDNA in electrode-embedded nanochannels

In the present study, we address theoretical approaches for the experimental results to investigate the flow dynamics of λDNA through a nanochannel in which two nanoelectrodes are integrated. In order to elucidate the relationship between the longitudinal ionic current and the electrophoresis of λDNA in the specific micro/nanofluidics, we develop a theoretical model for the macroscopic fluid dynamics in a Lagrangian framework. The measured current change associated with a single molecule translocation through the channel is explained by the principle of the Coulter counter that allowed to predict the conformation of λDNA. We also analyze the local velocity of λDNA passing through a nanoscaled confined channel. A result from the model is in considerable agreement with the experimental observations for the electrophoretic flow of λDNA. The basic knowledge obtained here may be useful in developing electrical methods for controlling the electrophoretic velocity of single-molecule DNA for realizing the nanopore sequencer.