Staggered-electromagnetophoresis with a Split-flow System for the Separation of Microparticles by a Hollow Fiber-embedded PDMS Microchip

Abstract

Recently, we have developed a new microchip separation method for microparticles utilizing electromagnetophoresis (EMP) under the concept of the free-flow technique. 27 EMP, which was the migration phenomenon based on the Lorentz force proposed for the first time by Kolin in 1953, 28 is a force induced on a particle placed in a magnetic and electric field 2016 © The Japan Society for Analytical Chemistry † To whom correspondence should be addressed. A novel microchip separation system for microparticles based on electromagnetophoresis (EMP) was developed. In this system, focusing and separation of flowing microparticles in a microchannel could be performed by staggered-EMP by controlling the electric current applied to the channel locally combined with the split-flow system for fractionation of eluates. To apply the electric current through the flushing medium in the microchannel, a hollow fiber-embedded microchip with multiple electrodes was fabricated. The hollow fiber was made by a semi-permeable membrane and could separate small molecules. This microchip allowed us to apply the electric current to a part of the microchannel without any pressure control device because a main channel contacted with the subchannels that had electrodes through the semi-permeable membrane. Moreover, the separation using this microchip was combined with the split-flow system at two outlets to improve separation efficiency. Using this system, with the split-flow ratio of 10:1, 87% of 3 μm polystyrene (PS) latex particles were isolated from a mixture of 3 and 10 μm particles. Even the separation of 6 and 10 μm PS particles was achieved with about 77% recovery and 100% purity. In addition, by controlling the applied current, size fractionation of polypropylene (PP) particles was demonstrated. Moreover, biological particles such as pollens could be separated with high separation efficiency by this technique.

Applications of magnetic and electromagnetic forces in micro-analytical systems

“…239 To overcome this disadvantage and improve the separation efficiency, they fabricated a microchip system composed of a 7 mm EMP focusing segment and 3 mm EMP separation segment, where the two EMP forces were applied inversely. 240 To keep the sample particles in a single flow channel, a micro-dialysis hollow fiber (o.d. 220 μm, i.d.…”

Fabrication of a Polydimethylsiloxane Fluidic Chip Using a Sacrificial Template Made by Fused Deposition Modeling 3D Printing and Application for Flow-injection Analysis

“…Among the many materials for fluidic chips, polydimethylsiloxane (PDMS) is typical because of its usefulness. [9][10][11][12][13][14][15][16] PDMS can be obtained commercially as a highly viscous liquid (e.g., Sylgard or Silpot) that becomes a flexible and optical clear solid by crosslinking polymerization in the presence of a curing agent. Thus, PDMS is suitable for fabricating complex-shaped fluidic chips.…”