Microfluidic feedback using impedance detection

• US 9,188,615 B2
• Filed: 05/08/2012
• Issued: 11/17/2015
• Est. Priority Date: 05/09/2011
• Status: Active Grant

• Current Assignee: Advanced Liquid Logic, Inc. (Illumina Incorporated)
• Original Assignee: Advanced Liquid Logic, Inc. (Illumina Incorporated)
• Inventors: Sturmer, Ryan, Srinivasan, Vijay, Sudarsan, Arjun
• Primary Examiner(s): DIETERLE, JENNIFER M
• Application Number:
  US14/116,553
• Publication Number:
  US 20140190830A1
• Time in Patent Office: 1,288 Days
• US Class Current: 1/1
• CPC Class Codes: B01L 2200/0621 Control of the sequence of chambers filled or emptied
• 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 2200/16 Reagents, handling or storing thereof
• CPC Class Codes: B01L 2300/0645 Electrodes
• CPC Class Codes: B01L 2300/0816 Cards, e.g. flat sample carriers usually with flow in two horizontal directions
• CPC Class Codes: B01L 2300/0829 Multi-well plates; Microtitration plates
• CPC Class Codes: B01L 2300/087 Multiple sequential chambers
• CPC Class Codes: B01L 2300/089 Virtual walls for guiding liquids
• CPC Class Codes: B01L 2400/0427 Electrowetting
• 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 3/502792 for moving individual droplets on a plate, e.g. by locally altering surface tension
• CPC Class Codes: G01N 27/048 for determining moisture content of the material
• CPC Class Codes: G01R 27/16 Measuring impedance of element or network through which a current is passing from another source, e.g. cable, power line

Abstract

Methods comprising measuring the impedance of the electrode produced by the excitation signal, wherein the impedance indicates presence of liquid at the electrode are disclosed. Computer readable mediums storing processor executable instructions for performing the method, and systems are also disclosed. The systems comprise a processor, memory and code stored in the memory that when executed cause the processor at least to: receive an output voltage signal, superimpose an excitation signal onto the output voltage signal to produce a superimposed signal, connect the superimposed signal to an electrode in a droplet actuator, suppress the output voltage signal, when detecting an impedance of the electrode, and measure the impedance of the electrode produced by the excitation signal, wherein the impedance indicates presence of liquid at the electrode.

Claims

1. A method, comprising:

(a) receiving an output voltage signal produced by a power supply;

(b) superimposing an excitation signal onto the output voltage signal to produce a superimposed signal;

(c) connecting the superimposed signal to an electrode in a droplet actuator;

(d) suppressing the output voltage signal when detecting an impedance of the electrode; and

(e) measuring the impedance of the electrode produced by the excitation signal, wherein the impedance indicates presence of liquid at the electrode.

2. The method of claim 1, wherein superimposing the excitation signal comprises adding the excitation signal to the output voltage signal.

3. The method of claim 1, wherein suppressing the output voltage signal comprises stopping the output voltage signal.

4. The method of claim 1, wherein suppressing the output voltage signal comprises disabling a switching action of the power supply.

5. The method of claim 1, wherein suppressing the output voltage signal comprises disabling the power supply.

6. The method of claim 1, further comprising receiving a suppression signal to suppress the output voltage signal from the power supply.

7. The method of claim 1, further comprising determining a saturation of the impedance.

8. The method of claim 1, further comprising:

(a) injecting the liquid into the droplet actuator; and

(b) stopping injection when the impedance indicates the liquid has flowed to the electrode.

9. The method of claim 1, further comprising:

(a) injecting the liquid into a gap in the droplet actuator; and

(b) stopping injection when the impedance indicates the liquid has flowed to the electrode.

10. The method of claim 1, further comprising:

(a) injecting the liquid into a reservoir in the droplet actuator; and

(b) stopping injection when the impedance indicates the liquid has flowed to the electrode.

11. The method of claim 1, further comprising:

(a) injecting the liquid to fill a reservoir in the droplet actuator; and

(b) stopping injection when the impedance indicates the liquid has flowed from the reservoir to the electrode.

12. The method of claim 1, further comprising:

(a) establishing a fluid path in the droplet actuator from an input port to a reservoir to the electrode;

(b) injecting the liquid through the input port to fill the reservoir; and

(c) stopping injection when the impedance indicates the liquid has flowed to the electrode.

13. The method of claim 1, further comprising:

(a) arranging an input port outside a boundary of a reservoir in the droplet actuator;

(b) forming a fluid path from the input port to the reservoir to the electrode;

(c) injecting the liquid through the input port to fill the reservoir; and

(d) stopping injection when the impedance indicates the liquid has flowed to the electrode.

25. The method of claim 1, further comprising:

(a) arranging an input port outside a boundary of a reservoir in the droplet actuator;

(b) forming a fluid path from the input port to the reservoir to the electrode;

(c) injecting the liquid through the input port to fill the reservoir; and

(d) stopping injection when the impedance indicates the liquid has flowed to the electrode.

14. A method, comprising:

(a) generating an output voltage by a power supply;

(b) storing charge produced by the output voltage;

(c) superimposing an excitation signal onto the output voltage to produce a superimposed signal;

(d) connecting the superimposed signal to an electrode in a droplet actuator;

(e) suppressing the output voltage from the power supply when detecting an impedance at the electrode;

(f) supplying the charge to the droplet actuator to activate the electrode during the impedance; and

(g) measuring the impedance produced by the excitation signal while the output voltage is suppressed, wherein the impedance indicates presence of liquid at the electrode.

15. The method of claim 14, wherein superimposing the excitation signal comprises adding the excitation signal to the output voltage.

16. The method of claim 14, wherein suppressing the output voltage comprises at least one of stopping the output voltage generated by the power supply, disabling a switching action of the power supply, and disabling the power supply during the impedance measurement.

17. The method of claim 14, further comprising activating a suppression signal to suppress the output voltage generated by the power supply.

18. The method of claim 17, further comprising deactivating the suppression signal to resume the output voltage generated by the power supply.

19. The method of claim 14, further comprising charging a capacitor to store the charge.

20. The method of claim 14, further comprising determining the impedance is saturated.

21. The method of claim 14, further comprising:

(a) injecting the liquid into the droplet actuator; and

(b) stopping injection when the impedance indicates the liquid has flowed to the electrode.

22. The method of claim 14, further comprising:

(a) injecting the liquid into a gap in the droplet actuator; and

(b) stopping injection into the gap when the impedance indicates the liquid has flowed to the electrode.

23. The method of claim 14, further comprising:

(a) injecting the liquid into a reservoir in the droplet actuator; and

(b) stopping injection into the reservoir when the impedance indicates the liquid has flowed to the electrode.

24. The method of claim 14, further comprising:

(a) establishing a fluid path in the droplet actuator from an input port to a reservoir to the electrode;

(b) injecting the liquid through the input port to fill the reservoir; and

(c) stopping injection when the impedance indicates the liquid has flowed to the electrode.

26. A system, comprising:

(a) a controller;

(b) memory; and

(c) the controller configured to;

(i) receive an output voltage signal;

(ii) superimpose an excitation signal onto the output voltage signal to produce a superimposed signal;

(iii) connect the superimposed signal to an electrode in a droplet actuator;

(iv) suppress the output voltage signal when detecting an impedance of the electrode; and

(v) measure the impedance of the electrode produced by the excitation signal, wherein the impedance indicates presence of liquid at the electrode.

27. The system of claim 26, wherein the controller is further configured to at least one of add the excitation signal to the output voltage signal, stop the output voltage signal, disable a switching action of the power supply, and disable the power supply.

28. The system of claim 26, wherein the controller is further configured to determine a saturation of the impedance.

29. The system of claim 26, wherein the controller is further configured to:

(a) cause injection of the liquid into the droplet actuator; and

(b) stop the injection when the impedance indicates the liquid has flowed to the electrode.

30. The system of claim 26, wherein the controller is further configured to:

(a) cause injection of the liquid into a gap in the droplet actuator; and

(b) stop the injection when the impedance indicates the liquid has flowed to the electrode.

31. The system of claim 26, wherein the controller is further configured to:

(a) cause injection of the liquid into a reservoir in the droplet actuator; and

(b) stop the injection when the impedance indicates the liquid has flowed to the electrode.

32. The system of claim 26, wherein the code further causes the processor to:

(a) cause the injection of the liquid to fill a reservoir in the droplet actuator; and

(b) stop the injection when the impedance indicates the liquid has flowed from the reservoir to the electrode.

33. The system of claim 26, wherein the controller is further configured to:

(a) cause injection of the liquid into an input port of a reservoir in the droplet actuator; and

(b) stop the injection when the impedance indicates the liquid has flowed along a fluid path from the reservoir to the electrode.

34. A non-transitory computer readable medium comprising:

(a) generating an output voltage by a power supply;

(b) storing charge produced by the output voltage;

(c) superimposing an excitation signal onto the output voltage to produce a superimposed signal;

(d) connecting the superimposed signal to an electrode in a droplet actuator;

(e) suppressing the output voltage from the power supply when detecting an impedance at the electrode;

(f) supplying the charge to the droplet actuator to activate the electrode during the impedance; and

(g) measuring the impedance produced by the excitation signal while the output voltage is suppressed, wherein the impedance indicates presence of liquid at the electrode.

35. The non-transitory computer readable medium of claim 34, further comprising instructions for at least one of adding the excitation signal to the output voltage, stopping the output voltage generated by the power supply, disabling a switching action of the power supply, and disabling the power supply during the impedance measurement.

36. The non-transitory computer readable medium of claim 34, further comprising instructions for activating a suppression signal to suppress the output voltage generated by the power supply.

37. The non-transitory computer readable medium of claim 36, further comprising instructions for deactivating the suppression signal to resume the output voltage generated by the power supply.

38. The non-transitory computer readable medium of claim 34, further comprising instructions for charging a capacitor to store the charge.

39. The non-transitory computer readable medium of claim 34, further comprising instructions for determining the impedance is saturated.

40. The non-transitory computer readable medium of claim 34, further comprising instructions for:

(a) injecting the liquid into the droplet actuator; and

(b) stopping injection when the impedance indicates the liquid has flowed to the electrode.

41. The non-transitory computer readable medium of claim 34, further comprising instructions for:

(a) injecting the liquid into a gap in the droplet actuator; and

(b) stopping injection into the gap when the impedance indicates the liquid has flowed to the electrode.

42. The non-transitory computer readable medium of claim 34, further comprising instructions for:

(a) injecting the liquid into a reservoir in the droplet actuator; and

(b) stopping injection into the reservoir when the impedance indicates the liquid has flowed to the electrode.

43. The non-transitory computer readable medium of claim 34, further comprising instructions for:

(a) injecting the liquid through an input port to fill a reservoir in the droplet actuator;

(b) stopping injection when the impedance indicates the liquid has flowed to the electrode.

44. The non-transitory computer readable medium of claim 34, further comprising instructions for:

(a) injecting the liquid into an input port of a reservoir in the droplet actuator; and

(b) stopping injection when the impedance indicates the liquid has flowed along a fluid path from the reservoir to the electrode.