METHODS FOR NON-THERMAL APPLICATION OF GAS PLASMA TO LIVING TISSUE

• US 20100145253A1
• Filed: 04/25/2006
• Published: 06/10/2010
• Est. Priority Date: 04/25/2005
• Status: Active Grant

• Current Assignee: Drexel University
• Original Assignee: Drexel University
• Inventors: Balasubramanian, Manjula, Fridman, Gregory, Fridman, Alexander, Gutsol, Alexander F., Friedman, Gennady
• Granted Patent: US 8,521,274 B2
• Time in Patent Office: Days
• US Class Current: 604/20
• CPC Class Codes: A61B 18/042 using additional gas becoming plasma
• CPC Class Codes: A61N 1/40 Applying electric fields by inductive or capacitive coupling microwave apparatus A61N5/00; Applying radio-frequency signals
• CPC Class Codes: H05H 1/2406 using dielectric barrier discharges, i.e. with a dielectric interposed between the electrodes
• CPC Class Codes: H05H 2240/20 Non-thermal plasma
• CPC Class Codes: H05H 2245/32 Surgery, e.g. scalpels, blades or bistoury; Treatments inside the body
• CPC Class Codes: H05H 2245/34 Skin treatments, e.g. disinfection or wound treatment

Abstract

Method for the non-thermal treatment of human or animal tissue with high-voltage electrical discharge plasma is disclosed. The disclosed method employs current through plasma and through tissue not for the purpose of heating the tissue, but instead to maintain the plasma proximate to the tissue being treated. Also disclosed is a method of limiting the current through plasma and through tissue to minimize tissue heating by placement of an insulator or semiconductor between an electrode and tissue resulting in generation of a high-voltage discharge similar to a dielectric barrier discharge. The disclosed non-thermal plasma treatment can be employed to promote coagulation of blood, sterilization, disinfection, re-connection of tissue, and treatment of tissue disorders without causing significant thermal tissue damage.

Claims

1. A method of non-thermal treatment of living tissue comprising the step of providing gas discharge plasma proximate to a surface of the living tissue by causing sufficient electrical current to pass through the tissue to provide said gas discharge plasma.

2. A method as claimed in claim 1, wherein a specific electric plasma discharge power of said gas discharge plasma is greater than 0.01 Watt/cm², averaged over one square millimeter of a treatment area.

3. A method as claimed in claim 1, wherein the specific electric plasma discharge power of said gas discharge plasma is greater than 0.1 Watt/cm², averaged over one square millimeter of a treatment area.

4. A method as claimed in claim 1, wherein the gas discharge is a high-voltage discharge, and a value of the electric field near the surface of the living tissue exceeds 200 V/mm in the moments of maximal current.

5. A method as claimed in claim 1, wherein the gas discharge is a high-voltage discharge, and a value of the electric field near the surface of the living tissue exceeds 500 V/mm in the moments of maximal current.

6. A method as claimed in claim 1, wherein a gas in the gas discharge plasma is air that naturally exists near the surface of the living tissue.

7. A method as claimed in claim 1, wherein a gas in the gas discharge plasma is a pure gas.

8. A method as claimed in claim 1, wherein a gas of the gas discharge plasma comprises additives of pure gases.

9. A method as claimed in claim 8, wherein said additives of pure gases comprise hydrogen peroxide, vapor of alcohols, methane, ethane, and other saturated and unsaturated hydrocarbons, and hydroxy-carbonic compounds.

10. A method as claimed in claim 1, wherein a gas in the gas discharge plasma is caused to flow relative to a treatment area.

11. A method as claimed in claim 1, wherein said treatment of living tissue is performed for the purpose of killing bacteria, viruses, micro-organisms, or destroying certain proteins that may exist on or within the said tissue.

12. A method as claimed in claim 1, wherein said treatment of living tissue is performed for the purpose of treating a disease or a wound.

13. A method as claimed in claim 1, wherein said treatment of living tissue is performed for the purpose of obtaining a cosmetic improvement.

14. A method as claimed in claim 1, wherein said treatment of living tissue is performed for the purpose of coagulating blood.

15. A method as claimed in claim 1, wherein said treatment of living tissue is performed for the purpose of destroying certain cells within a surface layer of the said tissue.

16. A method as claimed in claim 1, wherein said treatment of living tissue is performed for the purpose of triggering apoptosis of certain tissue cells.

17. A method as claimed in claim 1, wherein said treatment of living tissue is performed for the purpose of improving a mechanical connection between different parts of the tissue.

18. A method of generating a high-voltage plasma discharge for non-thermal treatment of living tissue comprising the step of sustaining plasma by electrical current between the tissue and a surface of an electrode connected by electrical conductor to a power supply, and wherein a current density in said plasma is limited by the presence of and insulator or a semiconductor between the tissue and the electrode.

19. A method as claimed in claim 18, wherein said electrode is a highly polarizable fluid.

20. A method as claimed in claim 18, wherein said insulator or said semiconductor is a solid covering at least a portion of said electrode surface.

21. A method as claimed in claim 18, wherein said electrode is segmented into a mesh-like structure.

22. A method as claimed in claim 18, wherein said insulator or said semiconductor completely insulates said electrode.

23. A method as claimed in claim 18, wherein said insulator or said semiconductor has small holes for electrical current with an effective size of from 10 microns to 300 microns.