We present a parametric experimental study of convective electrokinetic instability (EKI) in an isotropically etched, cross-shaped microchannel using quantitative epifluorescence imaging. The base state is a three-inlet, one-outlet electrokinetic focusing flow configuration where the centre sample stream and sheath flows have mismatched ionic conductivities. Electrokinetic flows with conductivi...

In this report, the status quo and recent progress in electrokinetics are reviewed. Practical rules are recommended for performing electrokinetic measurements and interpreting their results in terms of well-defined quantities, the most familiar being the ζ-potential or electrokinetic potential. This potential is a property of charged interfaces, and it should be independent of the technique use...

The electrokinetic surfaces of cells of the TA3 ascites tumour of the mouse and the M.Mel. 1 ascites tumour of the golden hamster have been studied for the past 3 years. It became evident that with regard to their electrophoretic mobility (E.P.M.), TA3 cells were stable and melanoma cells were not. Therefore, results discussed in this paper only refer to the melanoma 'subline' used for the pres...

In a recent paper in this journal, Jefimenko (Jefimenko O D 2001 J. Phys. A: Math. Gen. 34 6143–56) used time-dependent generalizations of the Coulomb and Biot–Savart laws to infer the existence of ‘electrokinetic’ and ‘magnetokinetic’ fields due to radial acceleration of charges in circular motion. It is shown here that for the stationary charge and current distributions discussed in Jefimenko...

Electrokinetic manipulation refers to the control of particle and cell motions using an electric field. It is an efficient technique for microfluidic applications with the ease of operation and integration. It, however, suffers from an intrinsic drawback of low throughput due to the linear dependence of the typically very low fluid permittivity. We demonstrate in this work a significantly enhan...

Electrokinetic, structural and surface chemical characterizations of both active and porous sublayers of a composite (polyamide/polysulfone) reverse osmosis membrane were carried out by different techniques: (i) electrochemical impedance spectroscopy (EIS) allows both electrical and geometrical characterizations using equivalent circuits as models; (ii) surface chemical composition of the activ...

This study reports a hybrid electrokinetic technique for label-free manipulation of pathogenic bacteria in biological samples toward medical diagnostic applications. While most electrokinetic techniques only function in low-conductivity buffers, hybrid electrokinetics enables effective operation in high-conductivity samples, such as physiological fluids (∼1 S m(-1)). The hybrid electrokinetic t...