Non-thermal disinfection of biological fluids using non-thermal plasma

• US 20040022669A1
• Filed: 04/30/2003
• Published: 02/05/2004
• Est. Priority Date: 05/07/2001
• Status: Active Grant

• Current Assignee: Regents of The University of Minnesota (University of Minnesota)
• Original Assignee: Regents of The University of Minnesota (University of Minnesota)
• Inventors: Lin, Xiangyang, Ma, Hongbin, Deng, Shaobo, Bowman, Robert J., Oyen, Duane P.M., Ruan, R. Roger, Chen, Paul L.
• Granted Patent: US 7,011,790 B2
• Time in Patent Office: Days
• US Class Current: 422/22
• CPC Class Codes: A23L 3/26 by irradiation without heating
• CPC Class Codes: A61L 2/0011 using physical methods
• CPC Class Codes: A61L 2/14 Plasma, i.e. ionised gases
• CPC Class Codes: A61M 1/168 Sterilisation or cleaning before or after use
• CPC Class Codes: A61M 1/1698 Blood oxygenators with or without heat-exchangers intracorporal A61M1/1678; manufacturing of membranes therefor B01D67/00; semi-permeable membranes for separation processes characterised by their properties B01D69/00; semi-permeable membranes characterised by their material B01D71/00
• CPC Class Codes: A61M 1/32 Oxygenators without membranes
• CPC Class Codes: A61M 1/36 Other treatment of blood in a by-pass of the natural circulatory system, e.g. temperature adaptation, irradiation ; Extra-corporeal blood circuits
• CPC Class Codes: A61M 1/3681 by irradiation
• CPC Class Codes: A61M 2205/75 with filters
• CPC Class Codes: B01J 19/088 giving rise to electric discharges for heating purposes H05B7/00; for the production of ozone C01B13/11, H01T19/00
• CPC Class Codes: B01J 2219/00038 Processes in parallel
• CPC Class Codes: B01J 2219/0809 employing two or more electrodes
• CPC Class Codes: B01J 2219/0828 Wires
• CPC Class Codes: B01J 2219/083 cylindrical
• CPC Class Codes: B01J 2219/0835 substantially flat
• CPC Class Codes: B01J 2219/0869 Feeding or evacuating the reactor
• CPC Class Codes: B01J 2219/0877 Liquid
• CPC Class Codes: B01J 2219/0896 Cold plasma
• CPC Class Codes: H01J 37/32348 Dielectric barrier discharge
• CPC Class Codes: H05H 1/24 Generating plasma nuclear fusion reactors G21B1/00; gas-filled discharge reactors H01J37/32
• CPC Class Codes: H05H 1/246 : the plasma being activated using external electrodes H05H1/245 takes precedence
• CPC Class Codes: H05H 2245/36 : Sterilisation of objects, liquids, volumes or surfaces

Abstract

A method and apparatus are provided for at least partially disinfecting biological fluid of a mammal, which comprises pathogens in addition to normal cellular fractions. The method includes placing the biological fluid in a reaction volume and contacting a non-thermal plasma with the biological fluid to thereby kill at least a portion of the pathogens within the biological fluid.

Claims

1. A method of at least partially disinfecting biological fluid of a mammal, which comprises pathogens, the method comprising:

(a) placing the biological fluid comprising pathogens in a reaction volume; and

(b) contacting a non-thermal plasma with the biological fluid to kill at least a portion of the pathogens within the biological fluid.

2. The method of claim 1 wherein the biological fluid comprises a blood component.

3. The method of claim 1 and further comprising:

(c) drawing the biological fluid from the mammal prior to placing the biological fluid in the reaction volume in step (a); and

(d) returning the biological fluid to the mammal after treating the biological fluid in step (b).

4. The method of claim 3 wherein:

step (c) comprises drawing the biological fluid from a blood circulatory system of the mammal; and

step (d) comprises returning the biological fluid to the blood circulatory system.

5. The method of claim 3 wherein:

step (c) comprises drawing the biological fluid from an organ of the mammal; and

step (d) comprises returning the biological fluid to the organ.

6. The method of claim 1 wherein steps (a) and (b) are performed internal to the mammal.

7. The method of claim 1 wherein the reaction volume is defined in a non-thermal plasma reactor and-wherein the method further comprises:

(c) carrying the non-thermal plasma reactor along an elongated shaft;

(d) inserting a portion of the shaft into the mammal in which the biological fluid is located; and

(e) performing steps (a) and (b) while the portion of the shaft is inserted into the mammal.

8. The method of claim 7 wherein step (e) comprises drawing the biological fluid into the shaft, passing the biological fluid through the reaction volume and then removing the biological fluid from the shaft after treatment in step (b).

9. The method of claim 7 wherein step (c) positioning the reaction volume at a distal end of the shaft and exposing the reaction volume to an area external to the shaft, and step (d) comprises positioning the distal end at a region in the internal cavity to be treated.

10. The method of claim 1 and further comprising:

(c) introducing gas bubbles into the biological fluid to generate a fluid-gas mixture; and

(d) treating the fluid-gas mixture with the non-thermal plasma during step (b).

11. The method of claim 10 and further comprising:

(e) removing the gas bubbles from the fluid-gas mixture after treating during step (d).

12. The method of claim 1 and further comprising:

(c) introducing a diluent into the biological fluid to generate a diluted biological fluid;

(d) treating the diluted biological fluid with the non-thermal plasma during step (b); and

(e) removing the diluent from the diluted biological fluid after treating during step (d).

13. The method of claim 12 wherein step (e) comprises passing the diluted biological fluid along a semi-permeable membrane having pore sizes that filter the diluent and pathogens having selected sizes from larger components of the biological fluid.

14. The method of claim 1 wherein:

step (a) comprises passing the biological fluid through the reaction volume between first and second electrodes while maintaining a gap in the reaction volume between the biological fluid and at least one of the first and second electrodes; and

step (b) comprises electrically exciting the first and second electrodes to generate the non-thermal plasma within the reaction volume.

15. The method of claim 14 and further comprising:

(c) providing a barrier in the reaction volume, which separates the reaction volume into a discharge initiation region and a treatment region, wherein the discharge initiation region defines the gap and is positioned between the first electrode and the treatment region, and the treatment region is positioned between the discharge initiation region and the second electrode; and

wherein step (a) comprises passing the biological fluid through the treatment region.

16. The method of claim 15 wherein the barrier comprises a dielectric material.

17. The method of claim 14 wherein step (b) comprises applying a substantially constant AC or DC voltage to the first and second electrodes.

18. The method of claim 1 wherein step (b) comprises reducing a number of the pathogens in the biological fluid by at least one log.

19. A circulating blood disinfection apparatus for at least partially disinfecting blood of a mammal, the apparatus comprising:

a first shunt for coupling to a circulatory system of the mammal and having a blood outlet;

a second shunt for coupling to the circulatory system of the mammal and having a blood inlet;

an inlet path coupled to the blood outlet of the first shunt for carrying the blood to be disinfected;

an outlet path coupled to the blood inlet of the second shunt for returning the blood to the mammal; and

a non-thermal plasma reactor comprising an inlet coupled to the inlet path, an outlet coupled to the outlet path, first and second electrodes, at least one dielectric barrier between the first and second electrodes, and a reaction volume between the first and second electrodes, wherein the reaction volume is coupled to the inlet and the outlet.

20. The apparatus of claim 19 wherein the non-thermal plasma reactor further comprises a discharge initiation region and a treatment region, wherein the discharge initiation region is positioned between the first electrode and the treatment region, and the treatment region is positioned between the discharge initiation region and the second electrode, and wherein the treatment region is coupled to the inlet and the outlet.

21. The apparatus of claim 20 wherein the non-thermal plasma reactor further comprises a barrier separating the discharge initiation region from the treatment region.

22. The apparatus of claim 19 and further comprising:

a gas injector coupled in the inlet path and having a gas inlet for receiving a gas to be injected into the blood being passed along the inlet path; and

a gas-liquid separator coupled along the outlet path.

23. The apparatus of claim 19 and further comprising:

a diluent inlet along the inlet path for receiving a diluent to be mixed with the blood; and

a membrane filter coupled along the outlet path and adapted to filter at least a portion of the diluent from the blood along the outlet path.

24. The apparatus of claim 23 wherein the membrane filter comprises a semi-permeable membrane having pore sizes that are smaller than the sizes of red and white blood cells.

25. A probe for insertion into a mammal, the probe comprising:

a shaft with a proximal end and a distal end;

an inlet and an outlet positioned along the shaft; and

a non-thermal plasma reactor carried along the shaft and comprising first and second electrodes, at least one dielectric barrier between the first and second electrodes, and a reaction volume between the first and second electrodes, wherein the reaction volume is coupled to the inlet and the outlet.

26. The probe of claim 25 and further comprising a pump located along a fluid travel path extending between the inlet and the outlet.

27. The probe of claim 25 wherein the non-thermal plasma reactor further comprises a discharge initiation region and a treatment region, wherein the discharge initiation region is positioned between the first electrode and the treatment region, and the treatment region is positioned between the discharge initiation region and the second electrode, and wherein the treatment region is coupled to the inlet and the outlet.

28. The probe of claim 27 wherein the non-thermal plasma reactor further comprises a barrier separating the discharge initiation region from the treatment region.

29. The probe of claim 28 wherein the treatment region is located at the distal end of the shaft and has a perimeter that is open to an exterior of the probe and defines the inlet and the outlet.

30. A biological fluid treatment apparatus comprising:

a biological fluid input for receiving biological fluid of a mammal, which comprises pathogens in the biological fluid;

means for introducing gas bubbles into the biological fluid received from the biological fluid input to produce a mixture of the biological fluid and the gas bubbles;

non-thermal plasma reactor means for receiving the mixture of the biological fluid and the gas bubbles within a reaction volume and for generating a non-thermal plasma within the reaction volume to thereby kill at least a portion of the pathogens within the biological fluid; and

a gas-liquid separator coupled to an output of the reactor means for separating the gas bubbles from the biological fluid.

31. A fluid comprising a mammalian biological fluid and a non-thermal plasma.