Development of microfluidic cell nucleus separator employing rapid chemical treatment

Separation/purification of nuclei from cells is a critical process required for medical and biochemical research applications. Here we report a microfluidic device to isolate cell nucleus by utilizing the concept of hydrodynamic filtration to chemically treat cells. When a cell suspension is continuously introduced into a microchannel (main channel) having multiple side channels, cells flow through the main channel while the carrier-medium of cells is drained through the branch channels. Introduction of a surfactant solution and a washing buffer enables the exchange of the carrier-medium twice, and cells were treated by the surfactant solution for a short span of time. By controlling the treatment (retention) time, cell membranes could be selectively digested while cell nuclei are maintained, which are further separated from cytoplasmic components according to size. We examined several types of surfactant molecules, and demonstrated that Triton X-100 showed the best separation efficiencies when JM cells were treated for 0.7-4.0 sec. In addition, the isolation efficiency of cell nucleus was evaluated by western-blotting. The presented cell-nucleus separator would become a useful means for various biological applications, because of its simplicity in operation, reproducibility, and high efficiency.