New research on cell sorting from a team at Nagoya University used a microfluidic chip to prevent sample infection and speed up the process. Their chip has microchannels. Cell suspensions are introduced for sorting through these microchannels. This research team integrated two externally-driven on-chip pumps into a microfluidic chip for high-speed flow control. They used a high-speed actuator as the driving source of the pump, which leads to a successful flow being produced with 16 microseconds for cell sorting.
Sorting individual cells is a necessary step for many biological applications, including the isolation of specific cell type from cell suspensions. Fluorescence-activated cell sorting (FACS) is used for high-throughput cell sorting. Lasers are used to excite auto-fluorescence or tagged-fluorescence of cells in droplets. Then the droplets are diverted into different containers, depending on the cell’s characteristics. This technique has long been standard but raises concerns about sample infections due to aerosols generation. Additionally, a FACS of larger cells requires the samples to be processed in low pressure through wider nozzles in order to prevent damage. This results in sorting limited to a low-level throughput.
An image showing the developed microfluidic chip. (Source: Shinya Sakuma, Yusuke Kasai, Takeshi Hayakawa, and Fumihito Arai)
"Target/non-target cells are three-dimensionally aligned in the main channel," corresponding author Shinya Sakuma said. "When target cells are detected, the on-chip pumps work rapidly to sort cells into one of two interest channels. Meanwhile, non-target cells are flushed into the waste channel without pump actuation."
This new technique allows researchers to sort large and small cells with high speed, high purity and high viability.
"We tested the method on microalgae as an example of large cells, around 100 micrometers in size, and achieved 95.8 percent purity, 90.8 percent viability, and a 92.8 percent success rate," corresponding co-author Yusuke Kasai said. "As a model small cell type, we used a cancer cell whose size is around 24 micrometers, and achieved 98.9 percent purity, 90.7 percent viability, and a 97.8 percent success rate."
A paper on this research called “On-chip cell sorting by high-speed local-flow control using dual membrane pumps” is published in Lab on a Chip.
