Microfluidic immunomagnetic cell separation using integrated permanent micromagnets

Abstract

In this paper, we demonstrate the possibility to trap and sort labeled cells under flow conditions using a microfluidic device with an integrated flat micro-patterned hard magnetic film. The proposed technique is illustrated using a cell suspension containing a mixture of Jurkat cells and HEK (Human Embryonic Kidney) 293 cells. Prior to sorting experiments, the Jurkat cells were specifically labeled with immunomagnetic nanoparticles, while the HEK 293 cells were unlabeled. Droplet-based experiments demonstrated that the Jurkat cells were attracted to regions of maximum stray field flux density while the HEK 293 cells settled in random positions. When the mixture was passed through a polydimethylsiloxane (PDMS) microfluidic channel containing integrated micromagnets, the labeled Jurkat cells were selectively trapped under fluid flow, while the HEK cells were eluted towards the device outlet. Increasing the flow rate produced a second eluate much enriched in Jurkat cells, as revealed by flow cytometry. The separation efficiency of this biocompatible, compact micro-fluidic separation chamber was compared with that obtained using two commercial magnetic cell separation kits.

Micro-magnet arrays for specific single bacterial cell positioning

“…These micron scaled magnetic flux sources, requiring neither an external magnetic field nor a power supply, have been used to fabricate compact autonomous devices for the trapping of magnetic particles [32] and of magnetically-labeled eukaryotic cells [33]. So as to be adaptable to several applications in the field of microbiology, two different strategies were employed to label cells magnetically and specifically using (1) immunomagnetic labeling, based on antibody-antigen interactions and (2) magnetic in situ hybridization relying on a specific DNA sequence detection [34].…”

Single living cell manipulation and identification using microsystems technologies

“…Cells of interest are targeted by the suitable selected frequencies 20,26,27 . The cells seen in the lower left part of the figure will not cross the comb-like electrode and will be directed to flow to the selected outlet.…”

“…Recently, several microfluidic platforms were reported 18 for detection, and separation of cells have been reported. Certain microfluidic devices use biomarkers that are selected for the specific cells to separate and differentiate 13,16,17,[19][20][21] . The commonly utilized biomarker of CTCs is epithelial cell adhesion molecule (EpCAM; antigen).…”

“…For separation as mentioned above, cells are suspended in a media with a mixture of water and sucrose/dextrose 20,26,27 . For cell detection, since the CP of the solution of sucrose/dextrose is very close to that of the cells, a mixture of glycerol with trypsin (water soluble triglyceride) is used in experiments due to its very low dielectric constant at RF frequencies.…”

Dual-mode on-demand droplet routing in multiple microchannels using a magnetic fluid as carrier phase

“…11,12 Among these modules, droplet sorting is one of the most important operations, and has been accomplished by utilizing various means, including a membrane valve, 13 surface acoustic wave, 14 dielectrophoresis, 15 Marangoni effect, 16 and magnetic field. [17][18][19][20][21][22] The microfluidic droplet sorting methods can be classified into two categories: passive and active. One popular sorting scheme relies on channel geometry and droplet size.…”