Inertia-Enhanced Pinched Flow Fractionation

Abstract

Separating target particles or cells from a heterogeneous mixture is often critical to many chemical and biomedical applications. Pinched flow fractionation (PFF) is a microfluidic technique that utilizes the laminar flow profile to continuously separate particles by size. We demonstrate that the flow-induced inertial lift force in microchannels can be exploited to significantly increase the particle displacement in PFF due to its strong size dependence. This inertia-enhanced PFF (iPFF) technique can offer at least one-order-of-magnitude higher particle throughput than PFF does at the same sheath flow rate. Moreover, it is able to work effectively in a large range of Reynolds number that spans more than 1 order of magnitude in the current study. In addition, iPFF is found to work most effectively in a rectangular microchannel with a width-to-height aspect ratio of around 2.

Continuous Microfluidic Particle Separation via Elasto-Inertial Pinched Flow Fractionation

“…We have demonstrated that eiPFF offers a much higher particle throughput and a much better separation resolution than the traditional PFF. Moreover, as it works most efficiently for Re of order 1, eiPFF fills perfectly into the gap of our recently proposed inertia-enhanced PFF (iPFF) technique 56 that requires Re of order 10 or more. This feature makes eiPFF suitable for particle and cell separation in microfluidic devices that typically process a limited amount of samples.…”

Microfluidic co-flow of Newtonian and viscoelastic fluids for high-resolution separation of microparticles

“…Coupled with the secondary flows induced in structured [14][15][16][17] or curved 18-21 microchannels, inertial microfluidics has been intensively used for enrichment, separation, and stretching measurement of cells and microparticles. In comparison with inertial microfluidics generally using Newtonian fluids as the carrier medium, viscoelastic microfluidics relies on the elasticity by adding synthetic or biological polymers into the carrier medium.…”

Sheathless electrokinetic particle separation in a bifurcating microchannel

“…1,2 Compared with the batch-wise separation methods such as electrophoresis 3 and field flow fractionation, 4 continuous-flow microfluidic separation techniques are more favored for their ease of integration with up/downstream components and their potential to achieve high throughput. 5,6 A variety of force fields, which can be either externally applied or internally induced, have been demonstrated to continuously separate particles in microfluidic devices [7][8][9] ranging from hydrodynamic [10][11][12][13] to electrical, 14,15 acoustic, 16 optical, 17 and magnetic 18 forces. Among them, the most widely used is dielectrophoresis (DEP), a force exerted on a particle by a non-uniform electric field.…”