Microfluidics and small volume mixing based on redox magnetohydrodynamics methods

• US 7,147,441 B2
• Filed: 12/12/2002
• Issued: 12/12/2006
• Est. Priority Date: 12/20/2000
• Status: Expired due to Term

• Current Assignee: Board of Trustees of The University of Arkansas NA
• Original Assignee: Board of Trustees of The University of Arkansas NA
• Inventors: Aguilar, Zoraida P., Carter, Christopher S., Fritsch, Ingrid
• Primary Examiner(s): Rodriguez, William H.
• Application Number:
  US10/317,777
• Publication Number:
  US 20030118453A1
• Time in Patent Office: 1,461 Days
• Field of Search: 417/48, 417/49, 417/50, 417/53, 417/44, 417/45
• US Class Current: 417/48
• CPC Class Codes: B01F 33/3032 using magneto-hydrodynamic [MHD] phenomena to mix or move the fluids
• CPC Class Codes: B01L 2200/0605 Metering of fluids
• CPC Class Codes: B01L 2200/0647 Handling flowable solids, e.g. microscopic beads, cells, particles
• CPC Class Codes: B01L 2300/0887 Laminated structure
• CPC Class Codes: B01L 2300/12 Specific details about materials
• CPC Class Codes: B01L 2400/0415 electrical forces, e.g. electrokinetic
• CPC Class Codes: B01L 2400/043 magnetic forces
• CPC Class Codes: B01L 3/502707 characterised by the manufacture of the container or its components by shaping or joining plastic parts B29C59/00, B29C65/00; by laminating B32B37/00; manufacture of microstructural devices in general B81C
• 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 3/502784 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: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: F04B 17/00 Pumps characterised by combination with, or adaptation to, specific driving engines or motors
• CPC Class Codes: F04B 19/006 Micropumps F04B43/043 and F04B43/095 take precedence

Abstract

Microfluidic channels utilizing magnetohydrodynamics are used to pump very small volumes of solution. The channels have electrodes along the walls of the channel and a current carrying species within the solution carries the current through the solution. The electric field generated by the use of the current carrying species is perpendicular to a magnetic field applied to the channel. The combination of the electric and magnetic fields causes the solution to flow through the channel.

Claims

1. A microfluidic device comprising:

at least one microfluidic channel having a length;

at least two electrodes creating an electric field within the at least one channel wherein the field is perpendicular to the length of the channel by means of at least one anode and at least one cathode in the channel and opposite to each other;

a magnetic field within the channel and perpendicular to the electric field and the channel;

at least two solutions that are substantially immiscible, wherein at least one solution has a current carrying species, the current carrying species being capable of accepting at least one electron from the cathode and transferring the at least one electron to the anode such that the current carrying species does not accumulate upon the cathode or the anode and gaseous bubbles are not formed;

wherein the current carrying species is a redox compound;

wherein the electric field and the magnetic field induce the solution to flow in a direction perpendicular to both the electric field and the magnetic field.

2. The microfluidic device of claim 1 wherein said solution is an aqueous solution.

3. The microfluidic device of claim 1 wherein said solution is hydrophobic.

4. The microfluidic device of claim 1 further comprising at least one passive equilibration conductor within the channel and near the at least two electrodes.

5. The microfluidic device of claim 1 wherein the channel is less than one millimeter wide.

6. The microfluidic device of claim 1 wherein said channel is constructed from at least one layer of ceramic tape.

7. The microfluidic device of claim 1 further comprising a plurality of channels.

8. The microfluidic device of claim 7 wherein the plurality of channels is interconnected.

9. The microfluidic device of claim 1 wherein the solution having the current carrying species includes conductive nanoparticles.

10. The microfluidic device of claim 1 wherein at least one solution is nonaqueous.

18. The microfluidic device of claim 10 further comprising a rinse solution within a rinse solution reservoir, said reservoir being connected to the assay structure by a rinse conduit and being pushed through the rinse conduit by the force of an immiscible solution propelled by magnetohydrodynamic means.

19. The microfluidic device of claim 10 further comprising a secondary analyte binding material in solution within a secondary analyte binding material reservoir, said reservoir being connected to the assay structure by a secondary analyte binding solution conduit, wherein the secondary analyte binding solution is pushed through the secondary analyte binding conduit by the force of an immiscible solution propelled through the secondary analyte binding solution conduit by magnetohydrodynamic means.

11. A magnetohydrodynamic microfluidic device for performing assays comprising:

at least one assay structure having a cathode and an anode;

at least one conduit for applying a sample to the assay structure;

at least one first solution within the at least one conduit;

at least one second solution within the at least one conduit;

wherein the at least one first solution and the at least one second solution are immiscible;

wherein the first solution is pushed through the at least one conduit by the force of the at least one second solution being a propelled by magnetohydrodynamic means, said second solution comprising a current carrying species, the current carrying species being capable of repeatedly accepting at least one electron from the cathode and transferring the at least one electron to the anode such that the current carrying species does not accumulate upon the cathode or the anode and gaseous bubbles are not formed; and

,

at least one immiscible fluid plug in the at least one conduit capable of preventing the mixing of the at least aqueous solutions.

12. The microfluidic device of claim 11 further comprising a rinse solution within a rinse solution reservoir, said reservoir being connected to the assay structure by a rinse conduit.

13. The microfluidic device of claim 12 wherein the rinse solution comprises a current carrying species and is propelled through the rinse conduit by magnetohydrodynamic means.

14. The microfluidic device of claim 12 wherein the rinse solution is pushed through the rinse conduit by the force of an immiscible solution being propelled through the rinse conduit by magnetohydrodynamic means.

15. The microfluidic device of claim 11 further comprising a secondary analyte binding material in solution within a secondary analyte binding material reservoir, said reservoir being connected to the assay structure by a secondary analyte binding solution conduit.

16. The microfluidic device of claim 15 wherein the secondary analyte binding solution comprises a current carrying species and is propelled through the secondary analyte binding solution conduit by magnetohydrodynamic means.

17. The microfluidic device of claim 15 wherein the secondary analyte binding solution is pushed through the secondary analyte binding conduit by the force of an immiscible solution propelled through the secondary analyte binding solution conduit by magnetohydrodynamic means.

20. A microfluidic device comprising:

at least one microfluidic channel having a length;

at least two electrodes creating an electric field within the at least one channel wherein the field is perpendicular to the length of the channel by means of at least one anode and at least one cathode in the channel and opposite to each other;

a magnetic field within the channel and perpendicular to the electric field and the channel;

at least two solutions that are substantially immiscible, wherein at least one solution has a current carrying species the current carrying species being capable of accepting at least one electron from the cathode and transferring the at least one electron to the anode such that the current carrying species does not accumulate upon the cathode or the anode and gaseous bubbles are not formed;

wherein the current carrying species is conductive nanoparticles;

wherein the electric field, and the magnetic field induce the solution to flow in a direction perpendicular to both the electric field and the magnetic field.

21. The microfluidic device of claim 20 wherein said solution is an aqueous solution.

22. The microfluidic device of claim 20 wherein said solution is hydrophobic.

23. The microfluidic device of claim 20 further comprising at least one passive equilibration conductor within the channel and near the at least two electrodes.

24. The microfluidic device of claim 20 wherein the channel is less than one millimeter wide.

25. The microfluidic device of claim 20 wherein said channel is constructed from at least one layer of ceramic tape.

26. The microfluidic device of claim 20 further comprising a plurality of channels.

27. The microfluidic device of claim 26 wherein the plurality of channels is interconnected.

28. The microfluidic device of claim 20 wherein the solution having the current carrying species includes a redox compound.

29. The microfluidic device of claim 20 wherein at least one solution is nonaqueous.

30. A microfluidic device comprising:

at least one microfluidic channel having a length, wherein the at least one channel is constructed from at least one layer of ceramic tape;

at least two electrodes creating an electric held within the at least one channel wherein the field is perpendicular to the length of the channel by means of at least one anode and at least one cathode in the channel and opposite to each other;

a magnetic field within the channel and perpendicular to the electric field and the channel;

at least two solutions that are substantially immiscible, wherein at least one solution has a current carrying species the current carrying species being capable of accepting at least one electron from the cathode and transferring the at least one electron to the anode such that the current carrying species does not accumulate upon the cathode or the anode and gaseous bubbles are not formed;

wherein the electric field and the magnetic field induce the solution to flow in a direction perpendicular to both the electric field and the magnetic field.

31. The microfluidic device of claim 30 wherein said solution is an aqueous solution.

32. The microfluidic device of claim 30 wherein said solution is hydrophobic.

33. The microfluidic device of claim 30 further comprising at least one passive equilibration conductor within the channel and near the at least two electrodes.

34. The microfluidic device of claim 30 wherein the channel is less than one millimeter wide.

35. The microfluidic device of claim 30 further comprising a plurality of channels.

36. The microfluidic device of claim 35 wherein the plurality of channels is interconnected.

37. The microfluidic device of claim 30 wherein the current carrying species is a redox compound.

38. The microfluidic device of claim 30 wherein the current carrying species is conductive nanoparticles.

39. The microfluidic device of claim 30 wherein at least one solution is nonaqueous.