Bactericidal efficacies of nebulized non-thermal atmospheric plasma-treated liquids

Abstract

Objectives. Antimicrobial activities of non-thermal atmospheric plasma-treated liquids on various bacterial and fungal strains in their planktonic and biofilm forms have been widely reported. Since most of the plasma-treated liquids are water based, they might be washed off certain surfaces and they cannot be applied for the infections of respiratory tract. In the present study we have tested antimicrobial activities of plasma-treated N-acetyl cysteine solution (NAC), phosphate buffered saline (PBS) solution and deionized water when nebulized over planktonic forms of E. coli and S. aureus. Methods. Antimicrobial activities of nebulized plasma-treated liquids were evaluated with zone of inhibition test and colony counting assay. Moreover pH of NAC, PBS solution and deionized water were measured before, after plasma treatment and during nebulization since low pH is well known consequence observed in plasma-treated liquids. Results. Our results have revealed that pH of plasma-treated NAC, PBS solution and DIW decreases after plasma treatment consistent with previous reports and does not change during nebulization. Moreover, antimicrobial activity assessment indicates that nebulized plasma-treated NAC shows the strongest antimicrobial activity, which leads complete inactivation of bacteria for 10³ to 10⁶ CFU/ml initial bacterial load and 5-log reduction for 10⁷ CFU/ml initial bacterial load on both E. coli and S. aureus. Conclusions. Plasma-treated liquids could retain their antimicrobial activity during nebulization and nebulization could be considered as a future alternative method for delivery of plasma-treated liquids for respiratory tract infections. 

Keywords

• Non-thermal plasma,plasma medicine,nebulization,antimicrobial,biomedical engineering

References

1. [1] Langmuir I. Oscillations in ionized gases. Proc Natl Acad Sci USA 1928;14:627-37.
2. [2] Fridman G, Friedman G, Gutsol A, Shekhter AB, Vasilets VN, Fridman A. Applied plasma medicine. Plasma Process Polym 2008;5:503-33.
3. [3] Haertel B, von Woedtke T, Weltmann KD, Lindequist U. Non-thermal atmospheric-pressure plasma possible application in wound healing. Biomol Ther (Seoul) 2014;22:477-90.
4. [4] Graves DB. The emerging role of reactive oxygen and nitrogen species in redox biology and some implications for plasma applications to medicine and biology. J Phys D Appl Phys 2012;45.
5. [5] Fridman G, Brooks AD, Balasubramanian M, Fridman A, Gutsol A, Vasilets VN, et al. Comparison of direct and indirect effects of non-thermal atmospheric-pressure plasma on bacteria. Plasma Process Polym 2007;4:370-5.
6. [6] Ercan UK, Wang H, Ji H, Fridman G, Brooks AD, Joshi SG. Nonequilibrium plasma-activated antimicrobial solutions are broad-spectrum and retain their efficacies for extended period of time. Plasma Process Polym 2013;10:544-55.
7. [7] Kong MG, Kroesen G, Morfill G, Nosenko T, Shimizu T, van Dijk J, et al. Plasma medicine: an introductory review. New J Phys 2009;11:115012.
8. [8] Laroussi M, Mendis DA, Rosenberg M. Plasma interaction with microbes. New J Phys. 2003;5:41.

9. [9] Tanaka H, Nakamura K, Mizuno M, Ishikawa K, Takeda K, Kajiyama H, et al. Non-thermal atmospheric pressure plasma activates lactate in Ringer's solution for anti-tumor effects. Sci Rep 2016;6:36282.
10. [10] Fathollah S, Mirpour S, Mansouri P, Dehpour AR, Ghoranneviss M, Rahimi N, et al. Investigation on the effects of the atmospheric pressure plasma on wound healing in diabetic rats. Sci Rep 2016;6:19144.
11. [11] Fridman G, Peddinghaus M, Balasubramanian M, Ayan H, Fridman A, Gutsol A, et al. Blood coagulation and living tissue sterilization by floating-electrode dielectric barrier discharge in air. Plasma Chem Plasma Process 2006;26:425-42.
12. [12] Nam SH, Lee HW, Cho SH, Lee JK, Jeon YC, Kim GC. High-efficiency tooth bleaching using non-thermal atmospheric pressure plasma with low concentration of hydrogen peroxide. J Appl Oral Sci 2013;21:265-70.
13. [13] Dolci LS, Quiroga SD, Gherardi M, Laurita R, Liguori A, Sanibondi P, et al. Carboxyl surface functionalization of poly (L-lactic acid) electrospun nanofibers through atmospheric non-thermal plasma affects Fibroblast morphology. Plasma Process Polym 2014;11:203-13.
14. [14] Kvam E, Davis B, Mondello F, Garner AL. Nonthermal atmospheric plasma rapidly disinfects multidrug-resistant microbes by inducing cell surface damage. Antimicrob Agents Chemother 2012;56:2028-36.
15. [15] Panngom K, Lee SH, Park DH, Sim GB, Kim YH, Uhm HS, et al. Non-thermal plasma treatment siminishes fungal viability and up-regulates resistance genes in a plant host. Plos One 2014;9:e99300.
16. [16] Alekseev O, Donovan K, Limonnik V, Azizkhan-Clifford J. Nonthermal dielectric barrier discharge (DBD) plasma suppresses Herpes Simplex Virus type 1 (HSV-1) replication in corneal epithelium. Transl Vis Sci Technol 2014;3:2.
17. [17] Julak J, Janouskova O, Scholtz V, Holada K. Inactivation of prions using electrical DC discharges at atmospheric pressure and ambient temperature. Plasma Process Polym 2011;8:316-23.
18. [18] Poor AE, Ercan UK, Yost A, Brooks AD, Joshi SG. Control of multi-drug-resistant pathogens with non-thermal-plasma-treated alginate wound dressing. Surg Infect 2014;15:233-43.
19. [19] Yorsaeng S, Pornsunthorntawee O, Rujiravanit R. Preparation and characterization of chitosan-coated DBD plasma-treated natural rubber latex medical surgical gloves with antibacterial activities. Plasma Chem Plasma Process 2012;32:1275-92.
20. [20] Monetta T, Scala A, Malmo C, Bellucci F. Antibacterial activity of cold plasma-treated titanium alloy. 2011;1:205-14.
21. [21] Yost AD, Joshi SG. Atmospheric nonthermal plasma-treated PBS inactivates Escherichia coli by oxidative DNA damage. Plos One 2015;10:e0139903.
22. [22] Ma R, Wang G, Tian Y, Wang K, Zhang J, Fang J. Non-thermal plasma-activated water inactivation of food-borne pathogen on fresh produce. J Hazard Mater 2015;300:643-51.
23. [23] Oehmigen K, Winter J, Hahnel M, Wilke C, Brandenburg R, Weltmann KD, et al. Estimation of possible mechanisms of Escherichia coli inactivation by plasma-treated sodium chloride solution. Plasma Process Polym 2011;8:904-13.
24. [24] Joshi SG, Cooper M, Yost A, Paff M, Ercan UK, Fridman G, et al. Nonthermal dielectric-barrier discharge plasma-induced inactivation involves oxidative DNA damage and membrane lipid peroxidation in Escherichia coli. Antimicrob Agents Chemother 2011;55:1053-62.
25. [25] Ercan UK, Smith J, Ji HF, Brooks AD, Joshi SG. Chemical changes in nonthermal plasma-treated N-Acetylcysteine (NAC) solution and their contribution to bacterial inactivation. Sci Rep 2016;6:20365.
26. [26] OCallaghan C, Barry PW. The science of nebulised drug delivery. Thorax 1997;52:S31-S44.
27. [27] Cahill OJ, Claro T, O'Connor N, Cafolla AA, Stevens NT, Daniels S, et al. Cold air plasma to decontaminate inanimate surfaces of the hospital environment. Appl Environ Microbiol 2014;80:2004-10.
28. [28] Lukes P, Dolezalova E, Sisrova I, Clupek M. Aqueous-phase chemistry and bactericidal effects from an air discharge plasma in contact with water: evidence for the formation of peroxynitrite through a pseudo-second-order post-discharge reaction of H2O2 and HNO2. Plasma Sources Sci Technol 2014;23:015019.
29. [29] Machala Z, Tarabova B, Hensel K, Spetlikova E, Sikurova L, Lukes P. Formation of ROS and RNS in water electro-sprayed through transient spark discharge in air and their bactericidal effects. Plasma Process Polym 2013;10:649-59.
30. [30] Brisset JL, Hnatiuc E. Peroxynitrite: a re-examination of the chemical properties of non-thermal discharges burning in air over aqueous solutions. Plasma Chem Plasma Process. 2012;32:655-74.
31. [31] Wu HY, Sun P, Feng HQ, Zhou H, Wang R, Liang Y, et al. Reactive oxygen species in a non-thermal plasma microjet and water system: generation, conversion, and contributions to bacteria inactivation-An analysis by electron spin resonance spectroscopy. Plasma Process Polym 2012;9:417-24.
32. [32] Chen CW, Lee HM, Chang MB. Influence of pH on inactivation of aquatic microorganism with a gas-liquid pulsed electrical discharge. J Electrostat 2009;67:703-8.
33. [33] Xia DS, Liu Y, Zhang CM, Yang SA, Wang SL. Antimicrobial effect of acidified nitrate and nitrite on six common oral pathogens in vitro. Chin Med J (Engl) 2006;119:1904-9.
34. [34] Dykhuizen RS, Frazer R, Duncan C, Smith CC, Golden M, Benjamin M, et al. Antimicrobial effect of acidified nitrite on gut pathogens: importance of dietary nitrate in host defense. Antimicrob Agents Chemother 1996;40:1422-5.
35. [35] Cunningham R, Mustoe E, Spiller L, Lewis S, Benjamin M. Acidified nitrite: a host defence against colonization with C. difficile spores? J Hosp Infect 2014;86:155-7.
36. [36] Oehmigen K, Hahnel M, Brandenburg R, Wilke C, Weltmann KD, von Woedtker. The role of acidification for antimicrobial activity of atmospheric pressure plasma in liquids. Plasma Process Polym 2010;7:250-7.
37. [37] Jorgensen JH, Ferraro MJ. Antimicrobial susceptibility testing: a review of general principles and contemporary practices. Clin Infect Dis 2009;49:1749-55.
38. [38] Humphries RM, McDonnell G. Superbugs on duodenoscopes: the challenge of cleaning and disinfection of reusable devices. J Clin Microbiol 2015;53:3118-25.