Pumps On Microfluidic Chips Speed Up Cell Sorting

A research group in Japan has developed a high-speed cell sorting method using dual on-chip pumps.

AsianScientist (Aug. 2, 2017) – Scientists in Japan have incorporated pumps into microfluidic chips to enable rapid sorting of cell suspensions. They report their results in Lab on a Chip.

The sorting of individual cells is necessary for many biological applications, including the isolation of specific cell types from cell suspensions. A fluorescence-activated cell sorting (FACS) has been used for high-throughput cell sorting. In this method, lasers are used to excite auto-fluorescence or tagged-fluorescence of cells encased in droplets, and the droplets are subsequently diverted into different containers depending on their characteristics.

However, this technique is prone to sample contamination due to the generation of aerosols. Additionally, FACS analysis of larger cells requires the samples to be processed under low pressure and passed through wider nozzles to prevent damage. Thus, sorting is a low throughput process.

In this study, researchers at Nagoya University performed cell sorting using a microfluidic chip to prevent sample contamination. Their chip has microchannels into which cell suspensions are introduced, a cross-shaped sorting area and a three-branched microfluidic channel.

Importantly, the research group integrated two externally-driven on-chip pumps for high-speed flow control in the microfluidic chip. Using a high-speed actuator as the driving source of the pumps, they succeeded in producing a flow with 16 microseconds for cell sorting.

“Target and non-target cells are three-dimensionally aligned in the main channel,” said Assistant Professor Shinya Sakuma of Nagoya University. “When target cells are detected, the on-chip pumps work rapidly to sort cells of interest into one of two distinct channels. Meanwhile, non-target cells are flushed into the waste channel without pump actuation.”

The technique allowed the researchers to sort not only large, but also small cells with high speed, high purity, and high viability.

“We tested the method on microalgae as an example of large cells, which are around 100 micrometers in size, and achieved 95.8 percent purity, 90.8 percent viability, and a 92.8 percent success rate,” said Assistant Professor Yusuke Kasai of Nagoya University. “As a model of small cell types, we used a type of 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.”

The article can be found at: Sakuma et al. (2017) On-chip Cell Sorting by High-speed Local-flow Control Using Dual Membrane Pumps.


Source: Nagoya University.
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