Electric tempest in a teacup: The tea leaf analogy to microfluidic blood plasma separation

Abstract

In a similar fashion to Einstein’s tea leaf paradox, the rotational liquid flow induced by ionic wind above a liquid surface can trap suspended microparticles by a helical motion, spinning them down towards a bottom stagnation point. The motion is similar to Batchelor [Q. J. Mech. Appl. Math. 4, 29 (1951)] flows occurring between stationary and rotating disks and arises due to a combination of the primary azimuthal and secondary bulk meridional recirculation that produces a centrifugal and enhanced inward radial force near the chamber bottom. The technology is thus useful for microfluidic particle trapping/concentration; the authors demonstrate its potential for rapid erythrocyte/blood plasma separation for miniaturized medical diagnostic kits.

Particle concentration via acoustically driven microcentrifugation: microPIV flow visualization and numerical modelling studies

“…In measurements made at heights above this value, there is evidence of a radial velocity directed outwards implying the existence of secondary flow recirculation up the central vortex column. Similar secondary meridional flow recirculations structures were first observed in Yeo et al (2006a) and Arifin et al (2007). Figure 11 provides a graphical representation of the vortex shape established within the drop.…”

“…The experimental and numerically computed threedimensional flow characteristics bear striking resemblance to Batchelor flows (Batchelor 1951) occurring in a cylindrical fluid column trapped between a rotating disk on top and a stationary one at the bottom (Pao 1972;Yeo et al 2006a;Arifin et al 2007). The fluid-solid interface through which the SAW interacts with the drop can be regarded as a no-slip boundary (akin to the bottom stationary disk in the example above), due to the fact that the SAW radiates through only a small area of the contact footprint of the drop.…”

MicroPIV and micromixing study of corona wind induced microcentrifugation flows in a cylindrical cavity

“…2c. The latter flow behavior thus constituted the first concept of a microcentrifuge that does not require the bulk rotation of the entire fluidic chamber or any other mechanically moving parts, and was demonstrated as an effective micromixer as well as a mechanism to separate or concentrate particles (Yeo et al 2006b)-for example, the separation of red blood cells from blood plasma (Yeo et al 2006a;Arifin et al 2007).…”

Rapid bioparticle concentration and detection by combining a discharge driven vortex with surface enhanced Raman scattering

“…This flow field has been shown to be able to separate red blood cells from the plasma in blood samples as a microfluidic blood separator. 25 As the convection velocity exceeds 1 cm/ s, the trapping is rapid. Hence, this far-reaching microflow significantly extends the domain of attraction of short-range DEP traps.…”