Separation of particles based on size is one of the essential components in biochemical analysis, environmental assays, and industrial and biomedical applications. Filtration is one of the most frequently used techniques to separate particles. A mechanical filter can be used to remove, filter, or collect particles. This filtering and collection of particles can be used for sampling of particles, chemical detection, and/or biological cell analysis.

Existing filtration methods are performed in a batch or a continuous manner. However, when the particle size is much smaller or when the difference in particle size is small, separation becomes difficult. Pore clogging or membrane fouling may be an issue.

The present invention provides a streamline-based device and a method for using the device for continuous separation of particles including cells in biological fluids. The device includes a main microchannel and an array of side microchannels disposed on a substrate. The main microchannel has a plurality of stagnation points with a predetermined geometric design; for example, each of the stagnation points has a predetermined distance from the upstream edge of each of the side microchannels. The particles are separated and collected in the side microchannels.

A microfluidic device is provided that includes components linked in fluid communication. The components include one or more sample inlet ports, one or more microchannels, and one or more outlet ports. The device is capable of sorting particles (such as cells) according to their characteristics, such as particle size and shape. The various components are compatible with various microscale systems. Moreover, the design is modular, which permits the addition of other elements (e.g., detectors, cell collection chambers, and the like).

The method includes administering a fluid containing a plurality of particles through the main microchannel, optionally applying a positive or a negative pressure to the main microchannel to separate each particle, and collecting the plurality of particles from each of the side microchannels. The particles to be separated include red blood cells and white blood cells.

Separation of specific cells from a mixed cell population is important in medicine for biological and immunological measurements, and for use in cell therapy (e.g., transfusion medicine). For example, in the medical field, it is often necessary to filter blood. Human blood cell separation is the first challenging step towards total blood count and the subsequent disease diagnosis, prognosis, and management.

This device is not limited to the separation of in vitro particles, but can also be used to separate particles in a biological environment, such as cells, fibrins, bacteria, microorganisms, particulates, and the like.

This work was done by Yu-Chong Tai, Siyang Zheng, and Harvey Kasdan of Caltech for Johnson Space Center. NASA is seeking partners to further develop this technology through joint cooperative research and development. For more information about this technology and to explore opportunities, please contact This email address is being protected from spambots. You need JavaScript enabled to view it.. MSC-25025-1


NASA Tech Briefs Magazine

This article first appeared in the May, 2016 issue of NASA Tech Briefs Magazine.

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