Magnetohydrodynamic microfluidic systems including modified electrodes and methods of using the same

• US 9,989,452 B2
• Filed: 11/24/2015
• Issued: 06/05/2018
• Est. Priority Date: 11/25/2014
• Status: Expired due to Fees

• Current Assignee: The Board of Trustees of the University of Arkansas (University of Arkansas System)
• Original Assignee: The Board of Trustees of the University of Arkansas (University of Arkansas System)
• Inventors: Fritsch, Ingrid, Nash, Christena, Kumar, Sai, Muldoon, Timothy, Balachandran, Kartik, Claycomb, Adair, Gerner, Matthew D., Hutcheson, Joshua, Khan, Foysal Z., Powless, Amy, Prieto, Sandra, Scrape, Preston G., Weston, Melissa C.
• Primary Examiner(s): Phasge, Arun S
• Application Number:
  US14/951,322
• Publication Number:
  US 20160146756A1
• Time in Patent Office: 924 Days
• Field of Search: None
• CPC Class Codes: B01F 33/3032 using magneto-hydrodynamic [MHD] phenomena to mix or move the fluids
• CPC Class Codes: B01L 2200/0647 Handling flowable solids, e.g. microscopic beads, cells, particles
• CPC Class Codes: B01L 2300/0654 Lenses; Optical fibres
• CPC Class Codes: B01L 2300/0816 Cards, e.g. flat sample carriers usually with flow in two horizontal directions
• CPC Class Codes: B01L 2400/0415 electrical forces, e.g. electrokinetic
• CPC Class Codes: B01L 2400/043 magnetic forces
• 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 3/502761 specially adapted for handling suspended solids or molecules independently from the bulk fluid flow, e.g. for trapping or sorting beads, for physically stretching molecules investigating characteristics of particles G01N15/00
• CPC Class Codes: F04B 19/006 Micropumps F04B43/043 and F04B43/095 take precedence
• CPC Class Codes: G01N 15/1433 using image recognition
• CPC Class Codes: G01N 15/147 the analysis being performed on a sample stream
• CPC Class Codes: G01N 2015/016 White blood cells
• CPC Class Codes: G01N 2015/1486 Counting the particles
• CPC Class Codes: G01N 27/447 using electrophoresis

Abstract

A magnetohydrodynamic microfluidic system and a method of pumping a fluid using a magnetohydrodynamic system are disclosed. The method includes applying at least one of an electric current and an electric voltage to a first modified electrode and a second electrode to generate an ionic current between the first modified electrode and the second electrode and to cause a current carrying species to move to or from the modified electrode, applying a magnetic field perpendicular to an ionic current vector, the magnetic field and the ionic current combining to induce flow of the fluid in a direction perpendicular to the magnetic field and the ionic current vector, and maintaining fluid flow by recharging the modified electrode.

Claims

1. A microfluidic system comprising:

a first and second electrode, said first electrode comprising at least one modified electrode comprising an immobilized electroactive chemical species;

at least one power source adapted to create an ionic current that passes between said electrodes;

at least one magnet adapted to create a magnetic field that is perpendicular to said ionic current;

said system adapted receive a fluid; and

said magnetic field and said ionic current combine to induce flow of the fluid.

2. The microfluidic system of claim 1 wherein said second electrode is a modified electrode comprising an immobilized electroactive chemical species.

3. The microfluidic system of claim 1 further comprising an opening, said first and second electrodes opposingly located in said opening and said at least one magnet located outside of said opening.

4. The microfluidic system of claim 3 further comprising:

at least one chamber adapted to contain the fluid and said chamber adapted to receive a plurality of cells to be counted in the fluid;

an illumination source and sensor located outside of said electrodes;

a processor in communication with said sensor and adapted to count the cells; and

said illumination source produces a light sheet that produces a 2-dimensional convergence area at a focal plane within said chamber, whereby the cells are counted by determining the depth of focus of said convergence area, the amount of time imaging per the speed of the cells, and the density of cells in the fluid.

5. The microfluidic system of claim 4 wherein the system is adapted to reverse the flow of the fluid containing the cells at least once to repass the cells through said focal plane.

6. The microfluidic system of claim 4 wherein said chamber is larger than a cell.

7. The microfluidic system of claim 3 further comprising:

at least one chamber adapted to contain the fluid and said chamber adapted to receive a biological sample to be analyzed in the fluid;

an illumination source and sensor located outside of said electrodes; and

a processor in communication with said sensor and adapted to analyze the biological sample.

8. The microfluidic system of claim 7 further adapted to perform a three-part differential on blood by texture analysis wherein said imaging sensor is in communication with said processor to capture an image of an illuminated blood cell;

said processor is adapted to detect and differentiate minute variations in the morphologic features of the blood cell by texture analysis of the blood cell; and

said illumination source produces a light sheet that produces a 2-dimensional convergence area at a focal plane within said chamber, whereby the blood cells are counted by determining the depth of focus of said convergence area, the amount of time imaging per the speed of the blood cells, and the density of blood cells in the fluid.

9. The microfluidic system of claim 1 further comprising an opening, said first and second electrodes are concentric with one another within said opening, and said at least one magnet located outside said opening.

10. The microfluidic system of claim 9 wherein said first electrode is a disk and said second electrode is a ring, said first electrode opposingly located from said second electrode and said system induces a rotational flow of the fluid that decreases from a center of the system.

11. The microfluidic system of claim 1 further including two opposingly located magnets and said electrodes located in between said magnets.

12. The microfluidic system of claim 1 further comprising maintaining fluid flow by recharging said modified electrode.

13. The microfluidic system of claim 12 wherein the recharging comprises applying at least one of a varying voltage and a varying current to said electrodes and applying a varying magnetic field.

14. The microfluidic system of claim 12 wherein the recharging comprises applying at least one of a varying voltage and a varying current to said electrodes and applying a varying magnetic field.

15. The microfluidic system of claim 12 wherein the fluid flow during recharging of the modified electrode is approximately zero.

16. The microfluidic system of claim 12 wherein the fluid flow is a pulsed fluid flow during recharging.

17. The microfluidic system of claim 12 wherein the recharging comprises

applying at least one of a varying voltage and a varying current to the electrodes;

and

changing the direction of the magnetic field.

18. The microfluidic system of claim 1 further comprising applying at least one of a sinusoidal potential, a current waveform, and a step function to said electrodes while simultaneously altering the direction of the magnetic field.

19. The microfluidic system of claim 1 further comprising intermittently recharging the modified electrode.

20. The microfluidic system of claim 19 wherein the intermittently recharging comprises directing the flow of ionic current such that an ionic current vector, j, is in parallel with the magnetic field.

21. The microfluidic system of claim 19 wherein directing the flow of ionic current such that the ionic current vector, j, is in parallel with the magnetic field does not alter the magnetic field.

22. The microfluidic system of claim 19 wherein intermittently recharging the modified electrode comprises directing the magnetohydrodynamic force such that the absolute value of the magnetohydrodynamic force is greater than zero.