News Column

Patent Issued for Continuous-Flow Deformability-Based Cell Separation

July 22, 2014



By a News Reporter-Staff News Editor at Life Science Weekly -- A patent by the inventors Han, Jongyoon (Bedford, MA); Bow, Hansen (Rolling Hills Estates, CA); Abgrall, Patrick (Toulouse, FR), filed on October 6, 2010, was published online on July 8, 2014, according to news reporting originating from Alexandria, Virginia, by NewsRx correspondents (see also Massachusetts Institute of Technology).

Patent number 8771933 is assigned to Massachusetts Institute of Technology (Cambridge, MA).

The following quote was obtained by the news editors from the background information supplied by the inventors: "Change in cell stiffness is a characteristic of several hematological diseases. Examples of such diseases may involve red blood cells (e.g. malaria and sickle cell anemia), white blood cells (leukemia and leukostasis), and metastatic solid-organ tumor cells (circulating tumor cells and the more extreme carcinocythemia). Often, increases in blood cell stiffness lead to loss of the cells' ability to squeeze through capillaries, resulting in organ failure, coma, and ultimately death."

In addition to the background information obtained for this patent, NewsRx journalists also obtained the inventors' summary information for this patent: "In one embodiment, this invention provides a method of sorting a fluid mixture comprising a plurality of cells, said method comprising the steps of: i. loading a fluid mixture comprising a plurality of cells in a cell sorter comprising: a first substrate comprising plurality of parallel trenches, arranged at intervals, the trenches each have a contour of a pair of walls and a bottom. a second substrate positioned parallel to said first substrate, such that a spacing is formed between said first and said second substrates; a sample inlet to said sorter; a sample outlet from said sorter; ii. applying a force field at a non-zero angle with respect to the length of said trenches, whereby applying said force field allows for separation of said plurality of cells; and iii. collecting separated cells obtained in (b) from said sample outlet.

"In one embodiment, the separation is a result of the difference in cell deformability of different cells in said plurality of cells. In one embodiment, the separation is a result of the difference in cell stiffness of different cells in said plurality of cells. In one embodiment, the method is used for disease diagnosis and/or for treatment efficacy monitoring. In one embodiment, the method is used as a tool for drug screening. In one embodiment, the method is used for isolation of a sub-population of cells. In one embodiment, the cells are cancer cells.

"In one embodiment, the cell separation rate is less than 0.1 seconds per cell. In one embodiment, the cell separation rate ranges between 0.1-1 seconds per cell. In one embodiment, the method reduces or eliminates clogging of said sorter. In one embodiment, the force field at a non-zero angle with respect to the length of said trenches is an electrostatic force field. In one embodiment, the electrostatic force field provides an electroosmotic driving force for said fluid. In one embodiment, the force field is a pressure-driven fluid flow. In one embodiment, the fluid has an ionic strength of about 1-1000 mM.

"In one embodiment, the sorting is deformability-based. In one embodiment, the sorting is size-based. In one embodiment, the sorting is charge-based. In one embodiment, the depth of said trenches ranges between 10-100,000 nm. In one embodiment, the spacing between said second substrate and said first substrate ranges between 10-50,000 nm. In one embodiment, the width of said trenches ranges between 10-1,000,000 nm. In one embodiment, the length of said trenches ranges between 10 nm and 10 cm. In one embodiment, the sample inlet, the sample outlet or a combination thereof are in fluid communication with a reservoir. In one embodiment, voltage is applied to the reservoir. In one embodiment, the applied voltage is less than 1000 V. In one embodiment, pressure is applied to the reservoir. In one embodiment, the fluid mixture comprises a cell mixture. In one embodiment, the fluid mixture comprises a buffered solution. In one embodiment, the method further comprising the step of sorting a sample of said fluid mixture two or more times, wherein the pH or ionic strength of said buffered solution is varied at the time of said sorting.

"In one embodiment, the trenches comprise a material having a Young's Modulus of at least 500 kPa. In one embodiment, the ratio between the length of said trenches and the spacing between the first and second substrates is at least 3:1. In one embodiment, the ratio between the length of said trenches and the spacing between the first and second substrates ranges between 10:1 and 100:1.

"In one embodiment, the spacing between the second substrate and the first substrate is less than 50% of the spacing between the second substrate and the bottom of the trenches of the first substrate. In one embodiment, the spacing between the second substrate and the first substrate ranges between 10% and 70% of the spacing between the second substrate and the bottom of the trenches of the first substrate. In one embodiment, spacing between the first and the second substrate ranges between 0.1-10 .mu.m. In one embodiment, the sorter conducts fluid, when fluid is introduced in said sorter. In one embodiment, the sorter employs a force field for conducting the fluid through the sorter. In one embodiment, the direction of the force field is diagonally to the length of the trenches. In one embodiment, the direction of the force field is at a non-zero angle and at an angle that is less than 90 degrees with respect to the length of the trenches. In one embodiment, the force field is a fluid flow. In one embodiment, the force field is an electric field. In one embodiment, the sample inlet comprises sample loading ports. In one embodiment, the sample outlet comprises sample collection ports.

"In one embodiment, the first substrate, the second substrate, portions thereof or a combination thereof comprises PDMS, NOA 81, glass, silicon, SiO.sub.2 or a combination thereof. In one embodiment, the first substrate, the second substrate, portions thereof or a combination thereof comprises a transparent material. In one embodiment, the surface of the first substrate, the second substrate, portions thereof or a combination thereof are coated to reduce cell adhesion. In one embodiment, the sorter is part of a microchip. In one embodiment, the microchip is disposable."

URL and more information on this patent, see: Han, Jongyoon; Bow, Hansen; Abgrall, Patrick. Continuous-Flow Deformability-Based Cell Separation. U.S. Patent Number 8771933, filed October 6, 2010, and published online on July 8, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=8771933.PN.&OS=PN/8771933RS=PN/8771933

Keywords for this news article include: Massachusetts Institute of Technology.

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Source: Life Science Weekly


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