Continuous sorting of magnetic cells via on-chip free-flow magnetophoresis

Abstract

The ability to separate living cells is an essential aspect of cell research. Magnetic cell separation methods are among some of the most efficient methods for bulk cell separation. With the development of microfluidic platforms within the biotechnology sector, the design of miniaturised magnetic cell sorters is desirable. Here, we report the continuous sorting of cells loaded with magnetic nanoparticles in a microfluidic magnetic separation device. Cells were passed through a microfluidic chamber and were deflected from the direction of flow by means of a magnetic field. Two types of cells were studied, mouse macrophages and human ovarian cancer cells (HeLa cells). The deflection was dependent on the magnetic moment and size of the cells as well as on the applied flow rate. The experimentally observed deflection matched well with calculations. Furthermore, the separation of magnetic and non-magnetic cells was demonstrated using the same microfluidic device.

Separation enhancement in pinched flow fractionation

“…The separation in the two types of devices were compared and an amplification in the separation of up to 70% was achieved. Numerical [3][4][5][6][7][8][9][10][11][12][13][14] Pinched flow fractionation ͑PFF͒ is a microchip based size separation technique for nanometer to micrometer sized particles relying on a laminar flow sheet. The method was first demonstrated by Yamada et al, 15 where 15 and 30 m polystyrene microspheres were separated.…”

Particle-by-Particle Charge Analysis of DNA-Modified Nanoparticles Using Tunable Resistive Pulse Sensing

“…One family of nanomaterials favoured with purification strategies is Superparamagnetic Particles, SPPs. These particles allow for the removal of specific analytes from complex sample matrices using nothing more complicated than a hand held magnet 14,[20][21][22][23] and the use of SPPs has become increasingly common. When they are incorporated into fluidic devices they can be used to continuously sort cells and DNA from liquids 24 , and are integrated into a variety of detection platforms 14,24,25 .…”

Microfluidic conformal coating of non-spherical magnetic particles

“…27 Tsai et al 28 has showed coating of spherical magnetic particles in microfluidics, with magnetic forces applied to move the microparticles from the aqueous to the non-aqueous phase in a co-laminar flow geometry. Upon passage through the co-laminar interface, the microparticles are coated with a thin O(1) lm layer of the aqueous fluid.…”