New Microfluidic Device Speeds Up Cell Separation

Researchers in Japan have created a new method to sort suspended, living cells that required only 30 minutes and eliminated the need for labor-intensive sample pretreatment and chemical tagging techniques. While the device cannot entirely replace existing separation methods such as centrifuge and mesh filters, it opens the door to faster cell separation that may be useful in certain research and industrial areas, such as the preparation of cells for therapeutics, platelets, and cancer-fighting T-cells.

Led by Professor Fumito Maruyama at Hiroshima University, the team developed a prototype microfluidic chip that leverages dielectrophoresis—a process by which suspended particles are induced into movement by applying a non-uniform electric field—to gently sort cells but leave them intact. Since the strength of dielectrophoretic force depends on the size of the cell and its dielectric properties, this technique can be used to selectively separate cells based on these differences. 

“The device eliminated sample pretreatment and established cell separation by all-in-one operation in a lab-on-chip, requiring only a small volume (0.5-1 mL) to enumerate the target cells and completing the entire separation process within 30 minutes,” Maruyama says. “Such a rapid cell separation technique is in high demand by many researchers to promptly characterize the target cells.”

Dielectrophoresis could be particularly useful in separating living cells for medical research applications and the medical industry. Its most significant advantage over other methods is its simplicity. “In conventional cell separation methods such as commercially available cell sorters, cells are generally labeled with markers such as fluorescent substances or antibodies, and cells cannot be maintained in their original physical state,” Maruyama said. “Therefore, separating differently sized cells using microfluidic channels and dielectrophoresis has been studied as a potentially great method for separating cells without labeling.”

Other common medical industry uses of cell separation include removing unwanted bacteria cells from donated blood and separating stem cells and their derivatives, which are crucial for developing stem cell therapies.

“If enrichment of a certain cell type from a solution of two or more cell types is needed, our dielectrophoresis-based system is an excellent option as it can simply enable a continuous pass-through of a large number of cells. The enriched cells are then easily collected from an outlet port,” Maruyama added. “Future research may examine refinements, allowing us to use dielectrophoresis to target certain cell types with greater specificity.”

The team’s findings were published in iScience.