Microfluidic manipulation of fluids and reactions

• US 7,556,776 B2
• Filed: 09/08/2005
• Issued: 07/07/2009
• Est. Priority Date: 09/08/2005
• Status: Expired due to Fees

• Current Assignee: Brandeis University, President and Fellows of Harvard College (Harvard Corporation)
• Original Assignee: Brandeis University, President and Fellows of Harvard College (Harvard Corporation)
• Inventors: Weitz, David A., Link, Darren Roy, Fraden, Seth, Cristobal-Azkarate, Galder, Shim, Jung uk
• Primary Examiner(s): Gakh; Yelena G
• Assistant Examiner(s): XU, XIAOYUN
• Application Number:
  US11/221,585
• Publication Number:
  US 20070052781A1
• Time in Patent Office: 1,398 Days
• Field of Search: None
• US Class Current: 422/504
• CPC Class Codes: B01L 2200/0642 Filling fluids into wells by specific techniques
• CPC Class Codes: B01L 2200/0673 Handling of plugs of fluid surrounded by immiscible fluid
• CPC Class Codes: B01L 2200/10 Integrating sample preparation and analysis in single entity, e.g. lab-on-a-chip concept
• CPC Class Codes: B01L 2200/14 Process control and prevention of errors
• CPC Class Codes: B01L 2200/141 Preventing contamination, tampering
• CPC Class Codes: B01L 2300/0864 comprising only one inlet and multiple receiving wells, e.g. for separation, splitting
• CPC Class Codes: B01L 2300/0867 Multiple inlets and one sample wells, e.g. mixing, dilution
• CPC Class Codes: B01L 2300/0887 Laminated structure
• CPC Class Codes: B01L 2400/0487 fluid pressure, pneumatics
• CPC Class Codes: B01L 3/06 Crystallising dishes
• CPC Class Codes: B01L 3/502784 specially adapted for droplet or plug flow, e.g. digital microfluidics automatic analysis using a stream of discrete samples in a tube system G01N35/08
• CPC Class Codes: B01L 3/502792 for moving individual droplets on a plate, e.g. by locally altering surface tension
• CPC Class Codes: Y10T 156/1093 with covering of discrete laminae with additional lamina
• CPC Class Codes: Y10T 436/11 Automated chemical analysis
• CPC Class Codes: Y10T 436/2575 Volumetric liquid transfer

Abstract

The present invention relates generally to microfluidic structures, and more specifically, to microfluidic structures and methods including microreactors for manipulating fluids and reactions. In some embodiments, structures and methods for manipulating many (e.g., 1000) fluid samples, i.e., in the form of droplets, are described. Processes such as diffusion, evaporation, dilution, and precipitation can be controlled in each fluid sample. These methods also enable conditions within the fluid samples (e.g., concentration) to be controlled. Manipulation of fluid samples can be useful for a variety of applications, including testing for reaction conditions, e.g., in crystallization, chemical, and biological assays.

Claims

1. A method, comprising:

positioning a first droplet defined by a first fluid, and a first component within the first droplet, in a first region of a microfluidic network;

forming a first precipitate of the first component in the first droplet while the first droplet is positioned in the first region;

dissolving a portion of the first precipitate of the first component within the first droplet while the first droplet is positioned in the first region; and

re-growing the first precipitate of the first component in the first droplet.

2. A method as in claim 1, wherein the first precipitate comprises a crystal.

3. A method as in claim 1, wherein the first precipitate comprises largely non-crystalline material.

4. A method as in claim 1, wherein re-growing the first precipitate comprises growing a crystal of the first component.

5. A method as in claim 1, wherein the first droplet has a volume of less than 10 nanoliters.

6. A method as in claim 1, wherein re-growing the first precipitate in the first droplet occurs while the droplet is positioned within the first region.

7. A method as in claim 1, wherein the first region is a microwell.

8. A method as in claim 1, wherein the first precipitate is formed within the first droplet by decreasing the volume of the first droplet.

9. A method as in claim 1, wherein a portion of the first precipitate is dissolved within the first droplet by increasing the volume of the first droplet.

10. A method as in claim 1, wherein the first component is a protein.

11. A method as in claim 10, where the protein is a membrane protein.

12. A method as in claim 1, further comprising positioning a second droplet defined by a second fluid, and a second component within the second droplet, in a second region of the microfluidic network, wherein the second region is in fluid communication with the first region, forming a second precipitate of the second component in the second droplet, dissolving a portion of the second precipitate, and re-growing the second precipitate of the second component.

13. A method, comprising:

positioning a droplet defined by a first fluid, and a first component within the droplet, in a first region of a microfluidic network, the droplet being surrounded by a second fluid immiscible with the first fluid;

flowing a third fluid in a microfluidic channel in fluid communication with the first region and causing a portion of the second fluid to be removed from the first region;

changing the volume of the droplet and thereby changing a concentration of the first component within the droplet; and

allowing a concentration-dependent chemical process involving the first component to occur within the droplet.

14. A method as in claim 13, wherein the first region is a microwell.

15. A method as in claim 13, wherein the concentration-dependent chemical process comprises crystallization.

16. A method as in claim 13, wherein the concentration-dependent chemical process comprises a chemical or biological reaction.

17. A method as in claim 13, wherein the first fluid is aqueous.

18. A method as in claim 13, wherein the second fluid comprises an oil.

19. A method as in claim 18, wherein the oil is at least partially water soluble.

20. A method as in claim 13, wherein the third fluid is a gas.

21. A method as in claim 20, wherein the gas comprises air.

22. A method as in claim 20, wherein the gas comprises water vapor.

23. A method as in claim 13, wherein positioning the droplet comprises lowering the surface energy of the droplet in the first region relative to the droplet prior to being positioned in the first region.

24. A method, comprising:

positioning a first droplet defined by a first fluid, and a first component within the droplet, in a first region of a microfluidic network;

positioning a second droplet defined by a second fluid, and a second component within the droplet, in a second region of the microfluidic network, wherein the first and second droplets are in fluid communication with each other;

forming a first precipitate of the first component in the first droplet while the first droplet is positioned in the first region;

forming a second precipitate of the second component in the second droplet while the second droplet is positioned in the second region;

simultaneously dissolving a portion of the first precipitate and a portion of the second precipitate within the first and second droplets, respectively; and

re-growing the first precipitate in the first droplet and re-growing the second precipitate in the second droplet, while the first and second droplets are positioned in the first and second regions, respectively.

25. A method as in claim 24, wherein the first precipitate comprises a crystal.

26. A method as in claim 24, wherein the first precipitate comprises largely non-crystalline material.

27. A method as in claim 24, wherein re-growing the first precipitate comprises growing a crystal.