The Application of Plasma for SUMD

1. The Application of Plasma for SUMD Non-thermal Atmospheric Plasma (NTAP) Electrode MEM-031 Shawn Anderson William Borrell John Mattero Joseph Neal Royston Rodrigues Advisors: Dr. Y. Cho Dr. A. Fridman

2. OVERVIEW • Background Information • Mechanics & Experiments Conducted • Market Analysis • Design of Prototype • General Progress of Winter Term • Future Goals

3. BACKGROUND INFORMATION • Bacterial Contamination – widespread problem • “Sterilization” • A vital process • According to FDA1 – process that shows 12 log reduction – define Sterility Assurance Level • Low Temperature Sterilants with High Efficacy2 • Current Medical Sterilization methods • Electron Beam (E Beam) • Ethylene Oxide • Steam (Autoclaving)

4. NON-THERMAL PLASMA • Plasma – 4th state of matter • Depending on how energy provided can be thermal or non-thermal (cold) plasma • Non-thermal formed using • Electron Beam5 • Dielectric Barrier Discharge (DBD) • Dielectric barrier discharge • Created when high voltage is applied6 • Charge builds up on surface • Electrons that enter region form electron avalanche • Advantage as produces high energy electrons directly

5. Dielectric Barrier Discharge (DBD) High Voltage

6. PLASMA STERILIZATION MECHANISIMS • Sterilization  any process or procedure designed to eliminate microorganisms from a material or medium • Inactivation kinetics are not absolute • UV radiation • Heat • Effects of charged particles • Electrons and positively/negatively charge ions • Direct and indirect effects of Reactive species • O, -O2, O3, OH- , NO, NO2 , etc. Max-Planck Institute

7. 0.5 0.5 0 0 • AFM images showing morphological changes before (left column) and after (right column) 10 minutes of DBD treatment. 2.5 2.5 μm μm 0 0 Horizontal distance: 1.074 μm Vertical Distance: 463.45 nm Horizontal distance: 531.46 nm Vertical Distance: 108.39 nm

8. PLASMA STERILIZATION MECHANISMS Heat • Equilibrium Plasmas • Electrons transfer thermal energy to larger particles • Macro effects of gaseous temperature changes within the discharge gap • Temperatures great enough to degrade organic structures • Advantages of DBD Plasma • Nonequilibrium electrons recycled, do not transfer thermal energy to background atoms • Global increases in thermal energy have negligible effects • Applicable to heat sensitive material, safer to use

9. GERMICIDAL AGENTS OF FE-DBD (UV) Radiation • Known mechanisms • UV radiation causes Thymine base pair dimerization which inhibits mitosis by preventing DNA replication • UV (180-340 nm) • VUV (110-180 nm) • DBD Plasma • However, the germicidal effects of (UV) radiation are comparatively negligible during plasma treatment • Filtering out UV from plasma does not significantly inhibit sterilization • Lethal dosage  several mW*s*cm-2 (200-300nm)7 • Typical dosage  several µW*s*cm-2(200-300nm) 7

10. GERMICIDAL AGENTS OF FE-DBD Reactive Species • Plasma discharge in atmospheric gas creates reactive species • electron impact excitation • Dissociation • O, -O2, O3, OH- , NO, NO2 , etc. 8 • Compromise the integrity of the walls, coats and membranes of bacterial cells • Can be drawn in by bacteria in a “gluttonous” state • Reactive species react with proteins and other metabolic constituents in the cytoplasma causing damage and apoptosis e + O2 O + O + e O + O2 + M  O3 + M e + H2O  H + OH + e

11. Ionization by direct electron impact • Rate of ionization Where keo - Collisional Rate coefficient of electrons and neutral atoms, I – activation energy, Te – electron temperature • Frequency of ionization - Where ne = 3X1011 • Typical ionization time:

12. GERMICIDAL AGENTS OF FE-DBD Charged Particles • The electrons, negative and positive ions generated during DBD • Primary mechanism of inactivation • Constant polarization and depolarization can create forces that overcome the tensile strength of the cell membrane • Abnormal charge distribution can effect ion gated surface channels • High energy particles create reactive species

13. Results

14. Results

15. 3 Phases of Inactivation

16. 3 Phases of Inactivation

17. BUDGET

18. REPROCESSING SINGLE-USE MEDICAL DEVICES • Single-Use Medical Devices (SUD) • Scalpel handles, forceps, scissors, speculums, etc. • Defined as used, open, or expired • FDA and MDUFMA • Validated sterilization procedures must accompany 510K submissions • Requires similar standards as OEMs

19. WHY REPROCESS • If 1-2% of all SUDs were reprocessed, savings of $1,000,000,000/yr • Up to 50% savings when reprocessing once • 10 Million tons of waste diverted from landfills each year • Increased reliability

20. COMPETITIVE ADVANTAGES • Size • Scalable to large container size • Possible conveyor belt mechanism with automated sterilization • Efficacy • Proven to kill D. radiodurans, E. coli • Short duration exposure times • 30sec to 10hrs • Safety • Runs off 110V wall power supply • Non-thermal plasma safe to touch

21. DESIGN OVERVIEW • Market Driven • Maintain Simplicity • Uses DPI Technology

22. DESIGN CONSTRAINTS • Size – fit to existing power source • Minimize moving parts • Plasma dictates suitable materials and other requirements

23. DESIGN BASICS • Simple • Low Cost • Easy to manufacture

24. INSIDE VIEW

25. COMPONENT/ASSEMBLY DRAWINGS

26. COMPONENT/ASSEMBLY DRAWINGS

27. TEST ELECTRODE

28. GOALS FOR SPRING TERM • Completion of validation activities • PTFE, Ceramic, Nylon • Implementing the NTAP Electrode and Protocol into sterilization box • Testing actual medical devices in box contaminated with D. radiodurans and E. coli

29. Dr. Young Cho Dr. Alexander Fridman Dr. Greg Fridman Moogega Cooper Drexel Plasma Institute

30. REFERENCES 1 http://www.myendosite.com/cms/files/July_1998_ID478.pdf • http://www.unc.edu/depts/spice/dis/ICHE-1996-Feb-p87.pdf • http://www.devicelink.com/mddi/archive/02/09/003.html • http://books.google.com/books?id=3f-kPJ17_TYC&pg=PA351&lpg=PA351&dq=plasma+sterilization+medical+devices&source=bl&ots=KkCpEv8PFZ&sig=hvTIRX2UtewsEEo0qgKqcfs8ugQ&hl=en&ei=7P2tSfHpCIiSngeElojDBg&sa=X&oi=book_result&resnum=7&ct=result • http://www.swri.org/3pubs/ttoday/Spring96/ttoday2.htm • http://www.gregfridman.com/publications/documents/STAR-RyanRobinson.pdf • Laroussi, Mounir. "Low Temperature Plasma-Based Sterilization: Overview and State-of-the-Art." Plasma Processes and Polymers 2 (2005): 391-400. • Fridman, Gregory, Peter I. Lelkes, and Kenneth Barbee. "Physical and Biological Mechanisms of Plasma Interaction with Living Tissue." Prepublication (2007).