Study of the Effect of Electrophoresis on Transport of Biomolecules in Microreactors

The effect of electrophoresis (i.e., applying uniform electric field to use the natural charge of particles) on the transport of a sample (like biomolecules) in active microreactors is numerically investigated. Navier-Stokes equations are solved along with the equations of electrostatics, species mass transport in the buffer and chemical reaction kinetics at reactive surfaces. Unlike previous studies, in which the effect of the charge of the sample bulk on the electric field has been neglected (i.e., the assumption of electroneutrality), here space charge density is assumed to be nonzero. As a result, the governing equations become fully coupled. The efficiency of the microreactor device is analyzed for two different geometries commonly used in biomolecule separation (i.e., open channel and microcylinders). It is shown that the electroneutrality assumption can drastically influence the final adsorbed concentration depending on the device configuration. Average adsorbed surface concentration is compared for each case as a measure of the performance of the device. The plots depicting the influence of the electric field and nonzero space charge density on the bulk concentration profile and the velocity field are also presented and discussed.