Method and apparatus for fluid dispersion

• US 7,708,949 B2
• Filed: 12/28/2004
• Issued: 05/04/2010
• Est. Priority Date: 06/28/2002
• Status: Active Grant

• Current Assignee: President and Fellows of Harvard College (Harvard Corporation), The Governing Council of the University of Toronto (University of Toronto)
• Original Assignee: President and Fellows of Harvard College (Harvard Corporation), The Governing Council of the University of Toronto (University of Toronto)
• Inventors: Link, Darren R., Kumacheva, Eugenia, Bontoux, Nathalie, Anna, Shelley L., Garstecki, Piotr, Diluzio, Willow, Whitesides, George M., Stone, Howard A., Weitz, David A., Gitlin, Irina
• Primary Examiner(s): Warden; Jill
• Assistant Examiner(s): Kingan; Timothy G
• Application Number:
  US11/024,228
• Publication Number:
  US 20050172476A1
• Time in Patent Office: 1,953 Days
• Field of Search: 422/50, 422/68.1, 422/100, 422/81, 422/82, 436/43, 436/174, 436/180, 436/52, 436/53
• US Class Current: 422/502
• CPC Class Codes: B01F 2215/0431 Numerical size values, e.g. diameter of a hole or conduit, area, volume, length, width, or ratios thereof
• CPC Class Codes: B01F 2215/045 Numerical flow-rate values
• CPC Class Codes: B01F 23/41 Emulsifying
• CPC Class Codes: B01F 25/45 Mixers in which the materials to be mixed are pressed together through orifices or interstitial spaces, e.g. between beads B01F25/44 takes precedence
• CPC Class Codes: B01F 25/4521 the components being pressed through orifices in elements, e.g. flat plates or cylinders, which obstruct the whole diameter of the tube
• CPC Class Codes: B01F 33/3011 using a sheathing stream of a fluid surrounding a central stream of a different fluid, e.g. for reducing the cross-section of the central stream or to produce droplets from the central stream
• CPC Class Codes: B01L 3/5027 by integrated microfluidic structures, i.e. dimensions of channels and chambers are such that surface tension forces are important, e.g. lab-on-a-chip B01L3/5023 takes precedence; micromixers B01F33/30; microreactors for synthesis B01J19/0093; microcapillary devices in general B81B1/00
• CPC Class Codes: B05B 7/0408 with arrangements for mixing two or more liquids
• CPC Class Codes: B05B 7/0416 with arrangements for mixing one gas and one liquid
• CPC Class Codes: B05B 7/0441 with one inner conduit of liquid surrounded by an external conduit of gas upstream the mixing chamber
• CPC Class Codes: Y10S 516/924 Significant dispersive or manipulative operation or step in making or stabilizing colloid system
• CPC Class Codes: Y10S 516/927 in situ formation of a colloid system making or stabilizing agent which chemical reaction
• CPC Class Codes: Y10T 137/0324 With control of flow by a condition or characteristic of a fluid
• CPC Class Codes: Y10T 137/0329 Mixing of plural fluids of diverse characteristics or conditions
• CPC Class Codes: Y10T 137/206 Flow affected by fluid contact, energy field or coanda effect [e.g., pure fluid device or system]
• CPC Class Codes: Y10T 137/87346 Including mixing feature
• CPC Class Codes: Y10T 29/49002 Electrical device making
• CPC Class Codes: Y10T 436/2575 Volumetric liquid transfer

Abstract

A microfluidic method and device for focusing and/or forming discontinuous sections of similar or dissimilar size in a fluid is provided. The device can be fabricated simply from readily-available, inexpensive material using simple techniques.

Claims

1. A method comprising:

providing a microfluidic interconnected region having an upstream portion, a downstream portion, and a dimensional restriction defining the downstream portion of the microfluidic interconnected region, the interconnected region being connected at its upstream portion to two or more microfluidic inlet channels, wherein the dimensional restriction is formed by at least an extension of a wall defining the interconnected region, the extension being in a direction transverse to the flow of fluid in the interconnected region; and

creating discontinuous sections of a subject fluid at the interconnected region, at least some of the discontinuous sections having a maximum dimension of less than 100 microns.

2. The method of claim 1, comprising creating the discontinuous sections of the subject fluid by surrounding the subject fluid, at least in part, by a continuous fluid, in the upstream portion of the interconnected region, and focusing the continuous fluid surrounding the subject fluid, at least in part, with the dimensional restriction.

3. The method of claim 2, wherein the continuous fluid comprises oil.

4. The method of claim 2, wherein each the subject fluid and the continuous fluid have a flow rate, and the ratio of the flow rate of the subject fluid to the continuous fluid is less than 1:

5.

5. The method of claim 2, wherein the continuous fluid completely circumferentially surrounds the subject fluid.

6. The method of claim 1, wherein the subject fluid flows though the interconnected region at a constant rate.

7. The method of claim 1, wherein the interconnected region has a maximum cross-sectional diameter of less than 50 microns.

8. The method of claim 1, wherein the subject fluid comprises water.

9. The method of claim 2, wherein the continuous fluid is immiscible with the subject fluid within the time flame of formation of the discontinuous sections of the subject fluid.

10. The method of claim 1, wherein the microfluidic interconnected region, the upstream portion, and the downstream portion are each contained within a microfluidic device.

11. The method of claim 1, wherein the downstream portion has a largest dimension perpendicular to fluid flow of less than about 5 mm.

12. The method of claim 1, wherein the downstream portion has a largest dimension perpendicular to fluid flow of less than about 1 mm.

13. The method of claim 1, wherein at least some of the discontinuous sections have a maximum dimension of less than 80 microns.

14. The method of claim 1, wherein at least some of the discontinuous sections have a maximum dimension of less than 60 microns.

15. The method of claim 1, wherein at least some of the discontinuous sections have a maximum dimension of less than 40 microns.

16. The method of claim 1, wherein at least some of the discontinuous sections have a maximum dimension of less than 20 microns.

17. The method of claim 1, wherein the interconnected region is connected at its upstream portion to three or more microfluidic inlet channels.