# US 8,783,467 B2 · Bump array device having asymmetric gaps for segregation of particles > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,783,467 B2 - Document ID: US8783467B2 - Status: Granted - Kind: B2 - Application number: 13/708,425 - Filed: 2012-12-07 - Published: 2013-04-25 - Granted: 2014-07-22 - Earliest claimed: 2008-07-24 - Assignees: The Trustees of Princeton University - Applicants: The Trustees of Princeton University - Inventors: Kevin Loutherback; James C. Sturm; Robert Austin; Keith Morton; Jason Puchalla - Web page: https://patentgrep.com/patent/US8783467B2 ## CPC - B03B 5/00: Washing granular, powdered or lumpy materials; Wet separating (separating by pneumatic tables or by pneumatic jigs B03B4/00) - G01N 27/44791: {Microapparatus (sample containers with integrated microfluidic structures B01L3/5027)} - G01N 30/0005: {Field flow fractionation} - G01N 30/6095: {Micromachined or nanomachined, e.g. micro- or nanosize} - B01L 3/502753: {characterised by bulk separation arrangements on lab-on-a-chip devices, e.g. for filtration or centrifugation} - G01N 30/6069: {with compartments or bed substructure} - G01N 2030/528: {Monolithic sorbent material} - B03B: SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - B01L: CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE ## Abstract The disclosure relates to obstacle array devices (also known as bump array devices) for separating populations of particles by size. Improvements over previous obstacle array devices are realized by causing the fluid velocity profile across gaps between obstacles to be asymmetrical with respect to the plane that bisects the gap and is parallel to the direction of bulk fluid flow. Such asymmetry can be achieved by selecting the shape(s) of the obstacles bounding the gap such that the portions of the obstacles upstream from, downstream from or bridging the narrowest portion of the gap are asymmetrical with respect to that plane. Improvements are also realized by using obstacles that have sharp edges bounding the gaps. Other improvements are realized by selecting obstacle shapes such that the critical particle dimensions defined by the gaps in two different fluid flow directions differ. ## Claims ### Claim 1 A bump array device for segregating particles by size, the device comprising: a body defining a microfluidic flow channel for containing fluid flow in a first direction and an array of obstacles disposed within and extending across the microfluidic flow channel; the obstacles being arranged in rows and columns, wherein the rows define an array direction that differs from the first direction by a tilt angle (ε); the columns repeat periodically and have a periodicity that is equal to 1/ε, where ε is measured in radians; the obstacles in each respective column defining gaps between themselves through which the fluid can flow generally transversely with respect to the columns; and the obstacles being shaped such that surfaces of two obstacles defining a respective gap are asymmetrically oriented about a first plane that extends through the center of the respective gap and that is parallel to the first direction. ### Claim 2 (depends on 1) The device of claim 1, wherein the surfaces of each of the two obstacles defining a respective gap are non-parallel, substantially planar surfaces. ### Claim 3 (depends on 2) The device of claim 2, wherein each of the two obstacles defining a respective gap has a triangular cross-section. ### Claim 4 (depends on 1) The device of claim 1, wherein the surface of one of the two obstacles defining a respective gap is curved and the surface of the other obstacle defining the respective gap is substantially planar. ### Claim 5 (depends on 1) The device of claim 1, wherein the microfluidic flow channel is bounded by a pair of parallel, substantially planar surfaces between which the obstacles extend. ### Claim 6 (depends on 1) The device of claim 1, wherein the rows and columns are at an angle of 90 degrees with respect to one another. ### Claim 7 (depends on 1) The device of claim 1, wherein the shape of each of multiple obstacles in a column is substantially identical and symmetrical about a second plane that bisects each of the multiple obstacles. ### Claim 8 (depends on 7) The device of claim 7, wherein the shape of substantially all obstacles in the array is substantially identical. ### Claim 9 (depends on 1) The device of claim 1, further comprising a liquid completely filling the flow channel. ### Claim 10 (depends on 9) The device of claim 9, further comprising a fluid handling apparatus for providing liquid to, withdrawing liquid from, or both providing liquid to and withdrawing liquid from the microfluidic flow channel. ### Claim 11 (depends on 1) The device of claim 1, wherein the surface of at least one of the two obstacles is a planar surface upstream of the gap and has a sharp edge at the gap. ### Claim 12 A bump array device for segregating particles by size, the device comprising: a body defining a microfluidic flow channel for containing fluid flow in a first direction and a second direction; an array of obstacles disposed within and extending across the microfluidic flow channel; the obstacles being arranged in rows and columns, wherein the rows define an array direction that differs from the first direction by a tilt angle (ε); the columns repeat periodically and have a periodicity that is equal to 1/ε, where ε is measured in radians; the obstacles in each respective column defining gaps between themselves through which the fluid can flow in the first direction generally transversely with respect to the columns and through which the fluid can flow in the second direction generally transversely with respect to the column; and the obstacles being shaped such that the critical particle size for particles passing through each gap in the first direction is different than the critical particle size for particles passing through each of the gaps in the second direction. ### Claim 13 (depends on 12) The device of claim 12, wherein the first and second directions are offset at an angle of from 120 to 180 degrees. ### Claim 14 (depends on 12) The device of claim 12, wherein the first and second directions are offset by 180 degrees. ### Claim 15 (depends on 12) The device of claim 12, wherein the obstacles extend between essentially parallel faces of the microfluidic flow channel. ### Claim 16 (depends on 12) The device of claim 12, wherein the transverse cross-section of each of the two obstacles defining a respective gap is substantially triangular. ### Claim 17 A method of segregating particles, the method comprising: inducing movement of a fluid in a first direction in a flow channel having a multiplicity of obstacles disposed therein and extending thereacross; the fluid having the particles suspended therein; the obstacles being arranged in rows and columns, wherein the rows define an array direction that differs from the first direction by a tilt angle (ε); the columns repeat periodically and have a periodicity that is equal to 1/ε, where ε is measured in radians; the obstacles in each respective column defining gaps between themselves through which the fluid can flow generally transversely with respect to the columns; the obstacles being shaped such that the surfaces of two obstacles defining a respective gap are asymmetrically oriented about a first plane that extends through the center of the gap and that is parallel to the first direction; and whereby the velocity profile of fluid flow through the gap is asymmetrically oriented about the first plane and the critical particle size for particles passing through each respective gap adjacent to one of the two obstacles is different than the critical particle size for particles passing through each respective gap adjacent to the other of the two obstacles. ### Claim 18 A method of segregating particles, the method comprising: inducing discrete, alternate movement of a fluid in a first direction and a second direction, in a flow channel having a multiplicity of obstacles disposed therein and extending thereacross; the fluid having the particles suspended therein; the obstacles being arranged in rows and columns, wherein the rows define an array direction that differs from the first direction by a tilt angle (ε); the columns repeat periodically and have a periodicity that is equal to 1/ε, where ε is measured in radians; the obstacles in each respective column defining gaps between themselves through which the fluid can flow in the first direction generally transversely with respect to the columns and through which the fluid can flow in the second direction generally transversely with respect to the columns; the obstacles being shaped such that the critical particle size for particles passing through each gap in the first direction is different than the critical particle size for particles passing through each gap in the second direction; and whereby particles intermediate in size between i) the critical particle size for particles passing through each gap in the first direction and ii) the critical particle size for particles passing through each gap in the second direction are separated from other particles. ### Claim 19 A bump array device comprising a body defining a microfluidic flow channel for containing fluid flow in a first direction; an array of obstacles within and extending across the microfluidic flow channel and arranged in rows and columns, wherein the rows define an array direction that differs from the first direction by a tilt angle (ε); the columns repeat periodically and have a periodicity that is equal to 1/ε, where ε is measured in radians; the obstacles in each set of two proximal obstacles in a respective one of the columns are separated by a respective gap through which the fluid can flow generally transversely with respect to the columns; and the obstacles being shaped such that the surfaces of the two proximal obstacles defining each of the respective gaps are asymmetrically oriented about a plane that extends through the center of each of the respective gaps and is parallel to the first direction. ### Claim 20 A method of segregating particles, the method comprising: inducing movement of a fluid in a flow channel either in a first direction or alternating between the first direction and a second direction; the fluid having the particles suspended therein; the flow channel having a multiplicity of obstacles disposed therein and extending thereacross, the obstacles being arranged in rows and columns, wherein the rows define an array direction that differs from the first direction by a tilt angle (ε); the columns repeat periodically and have a periodicity that is equal to 1/ε, where ε is measured in radians; the obstacles in each set of two proximal obstacles in a respective one of the columns separated by a respective gap and through which the fluid can flow generally transversely with respect to the columns; and the obstacles being shaped such that the surfaces of obstacles in each set of two proximal obstacles separated by a respective gap are asymmetrically oriented about a plane that extends through the center of the respective gap.