Sorting various pluripotent state of iPSCs via magnetization of nanoclusters in microfluidic magnetophoresis devices

iPSCs are prone to randomly differentiate into any cell line, and it is hard to maintain cell population with high pluripotency level. Therefore, it is necessary to isolate homogenous populations of highly pluripotent iPSCs... [ view full abstract ]

iPSCs are prone to randomly differentiate into any cell line, and it is hard to maintain cell population with high pluripotency level. Therefore, it is necessary to isolate homogenous populations of highly pluripotent iPSCs for applying the iPSCs in reprogramming somatic cells into iPSCs or differentiating iPSCs into specific cells. FACS and MACS have been used for sorting specific cells, but both methods have underlying issues in time and efficiency. Therefore, we developed magnetophoresis system with microfluidic channel to overcome abovementioned flaws. It can sort cells with higher quality and faster than conservative methods.
We used iPSCs-specific surface marker (A) and differentiated cells-specific surface marker (CD44), and each marker was labelled synthesized 200 nm and 500 nm magnetic clusters (200-A NC, and 500-CD44 NC), respectively. Highly pluripotent iPSCs are tagged with only 200-A NC, and slightly differentiated cells are tagged with 200-A NC and 500-CD44 NC. The cells are multifractionated in magnetophoresis microfluidic system.
Consequently, magnetically cell separation in a microfluidic channel system containing five outlets was successfully performed. Cells were deflected and carried out into different outlet channels depending on their magnetization. The magnetization is decided by tagged magnetic particle size and amount, which is related with pluripotency state of iPSCs. The result showed that outlet 1, 3, 5 had non-tagged cells, highly pluripotent iPSCs, and slightly differentiated cells, respectively. This method allows for high-throughput, cell preservation, and successfully overcoming the current flaws of FACS and MACS.
A multifractionation method for magnetic cell separation has been presented and evaluated using a stem cell model. Magnetization differences according to size and amount of tagged NC showed remarkable potential for multifractionation of the target cells. The results that we have shown agree with pluripotency state of iPSCs. This system demonstrates the ability to separate various kinds of homogeneous and heterogeneous cells by taking advantage of a range of magnetizations.