In this paper we present the numerical simulation-based design of a new microfluidic device concept for electrophoretic mobility and (relative) concentration measurements of dilute mixtures. The device enables stationary focusing points for each species, where the locally applied pressure driven flow (PDF) counter balances the species’ electrokinetic velocity. The axial location of the focusing...

Electrokinetic phenomena have an important connection to microfluidics because electrolytes can be used to manipulate small masses of fluids by means of suitably applied electric fields. Fluids at such small scales appear both in various natural systems and in microdevices intended for applications ranging from gene sequencing and gene expression to micropixels in electronic paper. Perhaps one ...

The electrokinetic flow resistance (electroviscous effect) is predicted for steady state, pressure-driven liquid flow at low Reynolds number in a microfluidic contraction of rectangular cross-section. Calculations of the three dimensional flow are performed in parallel using a finite volume numerical method. The channel walls are assumed to carry a uniform charge density and the liquid is taken...

The interaction of dextrin and guar gum with pyrite has been investigated through adsorption, flotation, and electrokinetic measurements. The adsorption densities of the polysaccharides onto pyrite reveal a region of higher adsorption density in the pH range 7.5-11, with a maximum around pH 10 for both polymers. The isotherms exhibit Langmuirian behavior. The adsorption density of guar gum onto...

The electrokinetic flow resistance (electroviscous effect) is predicted for steady state, pressure-driven liquid flow at low Reynolds number in a microfluidic contraction of rectangular cross-section. Calculations of the three dimensional flow are performed in parallel using a finite volume numerical method. The channel walls are assumed to carry a uniform charge density and the liquid is taken...

Electrokinetic soil remediation is often impeded by the aggregation of small particles, within soil, during procedure. The porous network subsequently clogged which results in immediate process termination. In order to overcome this limitation, feasibility electrokinetic coupled simultaneously with two enhancing techniques was investigated: modified periodic polarity reversal and catholyte pH c...

Bacillus thuringiensis and recombinant Escherichia coli proteinaceous protoxins were subject to proteolysis and analyzed by capillary electrokinetic chromatography. Three resulting toxins (65 kDa) were baseline-resolved within 22 min using a 10 mM borate, pH 11 separation buffer consisting of 25 mM sodium dodecyl sulfate (SDS) and 30 mM phytic acid. The toxins displayed differential interaction...

We introduce an on-chip electrokinetic assay to perform high-sensitivity nucleic acid (NA) detection. This assay integrates electrokinetic sample focusing using isotachophoresis (ITP) with a background signal-removal strategy that employs photopatterened, DNA-functionalized hydrogels. In this multistage assay, ITP first enhances hybridization kinetics between target NAs and end-labeled compleme...

Previously we have reported a family of convective patterns formed by charge-stabilized aqueous colloidal suspensions under constant (dc) vertical electric fields [Y. Han and D. G. Grier, J. Chem. Phys. 122, 164701 (2005); and ibid. 125, 144707 (2006)]. These patterns form in the bulk when electrokinetic forces act in the opposite direction to gravity. Here, we report on cellular patterns that ...

The area of 'laboratory-on-a-chip', miniaturised or microfluidic analysis systems, is a rapidly developing field. At the microscale, electrokinetic processes become enhanced, and the advent of AC electrokinetics (EK) in recent years further promotes the development of electrokinetic devices for microfluidics. ACEK has demonstrated to manipulate fluids and polarisable particles at low voltages w...