Microfluidic system for analyzing nucleic acids

• US 20040086870A1
• Filed: 10/31/2002
• Published: 05/06/2004
• Est. Priority Date: 10/31/2002
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Childers, Winthrop D., Tyvoll, David
• Granted Patent: US 7,217,542 B2
• Time in Patent Office: Days
• US Class Current: 435/6
• CPC Class Codes: B01L 2200/027 for microfluidic devices
• CPC Class Codes: B01L 2200/0647 Handling flowable solids, e.g. microscopic beads, cells, particles
• 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 2300/023 Sending and receiving of information, e.g. using bluetooth
• CPC Class Codes: B01L 2300/024 Storing results with means integrated into the container
• CPC Class Codes: B01L 2300/0663 Whole sensors
• CPC Class Codes: B01L 2300/0809 rectangular shaped
• CPC Class Codes: B01L 2300/087 Multiple sequential chambers
• CPC Class Codes: B01L 2300/0874 Three dimensional network
• CPC Class Codes: B01L 2300/1827 using resistive heater
• CPC Class Codes: B01L 2400/0415 electrical forces, e.g. electrokinetic
• CPC Class Codes: B01L 2400/0487 fluid pressure, pneumatics
• CPC Class Codes: B01L 2400/0633 with moving parts
• CPC Class Codes: B01L 3/502715 characterised by interfacing components, e.g. fluidic, electrical, optical or mechanical interfaces
• CPC Class Codes: B01L 3/50273 characterised by the means or forces applied to move the fluids micropumps F04B19/006, of the membrane type F04B43/043
• CPC Class Codes: B01L 7/52 with provision for submitting samples to a predetermined sequence of different temperatures, e.g. for treating nucleic acid samples amplification or hybridisation processes per se C12Q1/68; controlling sequential reactions for synthesis B01J19/0046

Abstract

A system, including methods and apparatus, for microfluidic analysis of a nucleic acid target in a nucleic acid mixture. The system includes a method to preselect the target from the mixture before amplification. Preselection enriches the mixture for the target by retaining the target on a target-selective receptor and then removing unretained non-target nucleic acids. The preselected target then may be amplified from the enriched mixture and assayed. Devices configured to carry out the method are also disclosed.

Claims

1. A method of analyzing a nucleic acid target in a nucleic acid mixture of the target and non-target nucleic acids, the method comprising:

attracting the nucleic acid mixture to an electrode included in electronics formed on a substrate;

retaining the target selectively by binding the target to a receptor disposed near the electrode;

enriching the mixture for the target by removing unretained nucleic acids; and

amplifying the target from the enriched mixture.

2. The method of claim 1, wherein enriching includes moving the unretained nucleic acids at least partially by mechanically driven flow.

3. The method of claim 2, wherein moving is conducted under a binding stringency that is determined by at least one of heating and applying an electric field to the receptor.

4. The method of claim 1, wherein attracting and retaining are conducted in a first compartment, amplifying being conducted in a distinct second compartment.

5. The method of claim 1, further comprising detecting the amplified target.

6. The method of claim 1, the receptor being a nucleic acid that is at least substantially complementary to the target, the nucleic acid being connected to the electrode.

7. The method of claim 1, amplifying being conducted with nucleic acid primers that are each distinct from the receptor.

8. The method of claim 1, wherein the receptor is a first receptor, the method further comprising contacting a second receptor with the amplified target to assay the amplified target, the second receptor being configured to selectively bind the target.

9. The method of claim 8, each of retaining and contacting being performed with a binding stringency, the stringency of contacting being greater than the stringency of retaining.

10. The method of claim 8, the first and second receptors being identical.

11. The method of claim 10, enriching and contacting being conducted in a shared compartment.

12. The method of claim 8, amplifying and contacting being conducted in different compartments.

13. The method of claim 8, the first and second receptors being distinct structurally and separated spatially.

14. The method of claim 1, further comprising releasing the retained target before the step of amplifying.

15. The method of claim 1, further comprising moving the retained target before the step of amplifying.

16. A microfluidic device for analyzing a nucleic acid target in a nucleic acid mixture that includes the target, comprising:

a substrate portion at least partially defining a chamber, the substrate portion including a substrate and electronics formed on the substrate, the electronics including at least first and second electrodes, each electrode being operable to form an electric field in the chamber; and

first and second receptors for specifically binding the target, the first and second receptors being distinct and connected to the first and second electrodes, respectively.

17. The device of claim 16, the chamber being plural chambers, the first and second electrodes being disposed in different chambers.

18. The device of claim 16, the electronics including a heating device that is operable to reverse binding of the target to the first receptor.

19. The device of claim 16, further comprising a fluid-handling portion connected to the substrate portion and configured to move fluid through the chamber at least partially by mechanically driven flow.

20. The device of claim 16, the first and second receptors being nucleic acids that are at least substantially complementary to a region of the target.

21. The device of claim 16, wherein the electronics include at least one nonconductive thin-film layer disposed near the chamber.

22. A microfluidic device for analyzing a nucleic acid target in a nucleic acid mixture of the target and non-target nucleic acids, comprising:

a substrate portion at least partially defining fluidically connected first and second chambers, the substrate portion including a substrate and electronics formed on the substrate, the electronics including a first electrode operable to form an electric field in the first chamber and a second electrode operable to form an electric field in the second chamber; and

first and second receptors for specifically binding the target, the first and second receptors being connected to the first and second electrodes, respectively.

23. The device of claim 22, the first and second receptors being distinct.

24. The device of claim 22, the electronics including a heating device operable to reverse binding of the first receptor to the target.

25. The device of claim 22, further comprising a fluid-handling portion connected to the substrate portion and configured to move fluid to and receive fluid from the first chamber.

26. The device of claim 25, the fluid-handling portion being configured to move fluid at least partially by mechanically driven flow.

27. The device of claim 22, at least one of the first and second electrodes being plural electrodes.

28. A microfluidic device for analyzing a nucleic acid target in a nucleic acid mixture of the target and non-target nucleic acids, comprising:

a substrate portion at least partially defining a chamber, the portion including a substrate and electronics formed on the substrate, the electronics including an electrode configured to attract the nucleic acid mixture in the chamber;

a receptor connected to the electrode and configured to selectively bind the target from the attracted mixture; and

a fluid-handling portion connected to the substrate portion and configured to remove unbound non-target nucleic acids from the chamber and to deliver amplification reagents to the chamber.

29. The device of claim 28, the fluid-handling portion being configured to move fluid at least substantially by mechanically driven flow.

30. The device of claim 28, the fluid-handling portion defining plural chambers for storing reagents and receiving waste.

31. The device of claim 28, the fluid-handling portion being formed at least partially of plastic.

32. A microfluidic device for analyzing a nucleic acid target in a nucleic acid mixture of the target and non-target nucleic acids, comprising:

means for attracting the nucleic acid mixture, the attracting means including an electrode included in electronics formed on a substrate;

means for selectively retaining the target near the attracting means;

means for removing unretained nucleic acids to enrich the mixture for the target; and

means for thermally cycling the enriched mixture to amplify the target from the enriched mixture.

33. The device of claim 32, further comprising means for assaying the amplified target.

34. The device of claim 33, the means for assaying including a second means for retaining the target selectively.

35. The device of claim 32, the removing means including means for moving fluid mechanically.

36. The device of claim 32, the means for thermally cycling being included in the electronics.

37. A microfluidic device for analyzing a nucleic acid target in a nucleic acid mixture, comprising:

means for preselecting the target from the mixture;

means for amplifying the preselected target; and

means for assaying the preselected target after amplification.