Electrophoretic size separation of particles in a periodically constricted microchannel

Abstract

The size separation of Brownian particles with the same free mobility in an electrophoretic microchannel with alternating thick regions and narrow constrictions is studied theoretically. The electrophoretic mobility is field dependent and generally increases with field strength. In weak fields, Brownian diffusion dominates and the migration is controlled by the entrance effect. Therefore, smaller particles migrate faster than larger ones. In strong fields, however, the particle tends to follow electric field lines. Smaller particles are susceptible to Brownian motion and thus influenced by the nonuniform electric field in the well significantly. As a result, larger particles possess higher mobilities. Our simulation results agree with the experimental observations and provide guidance for efficient nanofluidic separation.

Dispersive transport of biomolecules in periodic energy landscapes with application to nanofilter sieving arrays

“…In our work, we use this formulation in two ways: in the subsections immediately following, using appropriate projections, we develop a 1-D formulation which under some conditions, allows analytical evaluation of (19) and (20). Subsequently, in order to validate this 1-D solution, we also solve the above set of equations in the full 2-D nanofilter geometry using a finite difference method.…”

“…Based on their experimental observations, Fu et al [17] developed an empirical model for biomolecular sieving in the Ogston regime (molecule characteristic size of the order of or smaller than pore size) and proposed empirical formulas for the effective molecule mobility in terms of a molecular partition coefficient and the field strength. Taking a different approach, a number of groups used stochastic particle simulation methods such as Brownian Dynamics (BD) and Dissipative Particle Dynamics (DPD) methods, to gain insight into the separation mechanism [7,8,18,19], mainly in terms of the effective mobility.…”

A study of effective diffusivity in porous scaffold by Brownian dynamics simulation

“…They reported that a decrease in the solute size generally increased its diffusivity. Recently, Cheng et al [19,20] used Brownian dynamics simulation to investigate the particle size effect on the diffusive escape and force driven transport in regularly arranged cavities. They attributed the effect to volume exclusion in the absence of hydrodynamic interaction.…”

Migration of DNA molecules through entropic trap arrays: a dissipative particle dynamics study

“…They proposed a simple kinetic theory [hernia nucleation in (Tessier et al 2002) or beachhead scenario in (Cheng et al 2008)] to obtain more insight into the separation mechanism. Crossing over the thin region of the channel requires the overcoming of the entropic barrier.…”