Electromagnetic microfluidic cell labeling device using on-chip microelectromagnet and multi-layered channels

We present a new design for a microfluidic cell sorting system in which microelectromagnets are implemented and the Joule heating energy is dissipated to maintain a biocompatible temperature. The microfluidic channel has a multi-layered structure for rapid separation in a high gradient magnetic field. The top and bottom layers of our device both contribute to separate the magnetically labeled bio-particles, such as animal cells and bacteria, in the vertical direction. Joule heat was exploited to supply the thermal energy to an active area of cell sample channels, and the channel temperature was maintained in the biocompatible range (37 °C) using cooling channels embedded in the top channel layer. We numerically analyzed heat transfer for an on-chip electromagnet and solved the Joule heat problem of the device. Experimentally, we demonstrated the separation of a T-cell leukemia line, human Jurkat cells, utilizing immune-magnetophoresis. Magnetic beads with a characteristic polymer surface for coupling with CD3 T-cells made it possible to sort the human Jurkat cells with a labeling efficiency of greater than 95%. According to the cell viability test, the number of dead cells did not exceed 10% of the total, indicating that our cell sorting system did not cause any heat damage to the cells, despite utilizing electromagnets.