The emerged field of non-thermal plasma (NTP) shows great potential in the alteration of cell redox status, which can be utilized as a promising therapeutic implication. In recent years, the NTP field considerably progresses in the modulation of immune cell function leading to promising in vivo results. In fact, understanding the underlying cellular mechanisms triggered by NTP remains incomplete. In order to boost the field closer to real-life clinical applications, there is a need for a critical overview of the current state-of-the-art. In this review, we conduct a critical analysis of the NTP-triggered modulation of immune cells. Importantly, we analyze pitfalls in the field and identify persisting challenges. We show that the identification of misconceptions opens a door to the development of a research strategy to overcome these limitations. Finally, we propose the idea that solving problems highlighted in this review will accelerate the clinical translation of NTP-based treatments.

Department of Biomaterials and Biophysical Methods Institute of Experimental Medicine of the Czech Academy of Sciences 14220 Prague Czech Republic

Department of Optical and Biophysical Systems Institute of Physics of the Czech Academy of Sciences 18221 Prague Czech Republic

Institute for Clinical and Experimental Medicine 14021 Prague Czech Republic

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Keevil S.F. Physics and medicine: A historical perspective. Lancet. 2012;379:1517–1524. doi: 10.1016/S0140-6736(11)60282-1. PubMed DOI

Melzer A., Cochran S., Prentice P., MacDonald M.P., Wang Z., Cuschieri A. The importance of physics to progress in medical treatment. Lancet. 2012;379:1534–1543. doi: 10.1016/S0140-6736(12)60428-0. PubMed DOI

Babaeva N.Y., Naidis G.V. Modeling of plasmas for biomedicine. Trends Biotechnol. 2018;36:603–614. doi: 10.1016/j.tibtech.2017.06.017. PubMed DOI

Keidar M., Yan D., Beilis I.I., Trink B., Sherman J.H. Plasmas for treating cancer: Opportunities for adaptive and self-adaptive approaches. Trends Biotechnol. 2018;36:586–593. doi: 10.1016/j.tibtech.2017.06.013. PubMed DOI

Szili E.J., Hong S.H., Oh J.S., Gaur N., Short R.D. Tracking the penetration of plasma reactive species in tissue models. Trends Biotechnol. 2018;36:594–602. doi: 10.1016/j.tibtech.2017.07.012. PubMed DOI

Sung S.J., Huh J.B., Yun M.J., Chang B.M., Jeong C.M., Jeon Y.C. Sterilization effect of atmospheric pressure non-thermal air plasma on dental instruments. J. Adv. Prosthodont. 2013;5:2–8. doi: 10.4047/jap.2013.5.1.2. PubMed DOI PMC

Scholtz V., Pazlarova J., Souskova H., Khun J., Julak J. Nonthermal plasma—A tool for decontamination and disinfection. Biotechnol. Adv. 2015;33:1108–1119. doi: 10.1016/j.biotechadv.2015.01.002. PubMed DOI

De Geyter N., Morent R. Nonthermal plasma sterilization of living and nonliving surfaces. Annu. Rev. Biomed. Eng. 2012;14:255–274. doi: 10.1146/annurev-bioeng-071811-150110. PubMed DOI

Kubinova S., Zaviskova K., Uherkova L., Zablotskii V., Churpita O., Lunov O., Dejneka A. Non-thermal air plasma promotes the healing of acute skin wounds in rats. Sci. Rep. 2017;7:45183. doi: 10.1038/srep45183. PubMed DOI PMC

Chatraie M., Torkaman G., Khani M., Salehi H., Shokri B. In vivo study of non-invasive effects of non-thermal plasma in pressure ulcer treatment. Sci. Rep. 2018;8:5621. doi: 10.1038/s41598-018-24049-z. PubMed DOI PMC

Gilmore B.F., Flynn P.B., O’Brien S., Hickok N., Freeman T., Bourke P. Cold plasmas for biofilm control: Opportunities and challenges. Trends Biotechnol. 2018;36:627–638. doi: 10.1016/j.tibtech.2018.03.007. PubMed DOI

Smolkova B., Uzhytchak M., Lynnyk A., Kubinova S., Dejneka A., Lunov O. A critical review on selected external physical cues and modulation of cell behavior: Magnetic nanoparticles, non-thermal plasma and lasers. J. Funct. Biomater. 2018;10:2. doi: 10.3390/jfb10010002. PubMed DOI PMC

Lunov O., Zablotskii V., Churpita O., Jager A., Polivka L., Sykova E., Dejneka A., Kubinova S. The interplay between biological and physical scenarios of bacterial death induced by non-thermal plasma. Biomaterials. 2016;82:71–83. doi: 10.1016/j.biomaterials.2015.12.027. PubMed DOI

Lunov O., Churpita O., Zablotskii V., Deyneka I.G., Meshkovskii I.K., Jager A., Sykova E., Kubinova S., Dejneka A. Non-thermal plasma mills bacteria: Scanning electron microscopy observations. Appl. Phys. Lett. 2015;106:053703. doi: 10.1063/1.4907624. DOI

Rupf S., Lehmann A., Hannig M., Schafer B., Schubert A., Feldmann U., Schindler A. Killing of adherent oral microbes by a non-thermal atmospheric plasma jet. J. Med. Microbiol. 2010;59:206–212. doi: 10.1099/jmm.0.013714-0. PubMed DOI

Kalghatgi S.U., Fridman G., Cooper M., Nagaraj G., Peddinghaus M., Balasubramanian M., Vasilets V.N., Gutsol A.F., Fridman A., Friedman G. Mechanism of blood coagulation by nonthermal atmospheric pressure dielectric barrier discharge plasma. IEEE Trans. Plasma Sci. 2007;35:1559–1566. doi: 10.1109/TPS.2007.905953. DOI

Gweon B., Kim H., Kim K., Kim M., Shim E., Kim S., Choe W., Shin J.H. Suppression of angiogenesis by atmospheric pressure plasma in human aortic endothelial cells. Appl. Phys. Lett. 2014;104:133701. doi: 10.1063/1.4870623. DOI

Bekeschus S., Ressel V., Freund E., Gelbrich N., Mustea A., Stope M.B. Gas plasma-treated prostate cancer cells augment myeloid cell activity and cytotoxicity. Antioxidants. 2020;9:323. doi: 10.3390/antiox9040323. PubMed DOI PMC

Wolff C.M., Kolb J.F., Weltmann K.D., von Woedtke T., Bekeschus S. Combination treatment with cold physical plasma and pulsed electric fields augments ROS production and cytotoxicity in lymphoma. Cancers. 2020;12:845. doi: 10.3390/cancers12040845. PubMed DOI PMC

Sarangapani C., Patange A., Bourke P., Keener K., Cullen P.J. Recent advances in the application of cold plasma technology in foods. Annu. Rev. Food Sci. Technol. 2018;9:609–629. doi: 10.1146/annurev-food-030117-012517. PubMed DOI

Lopez M., Calvo T., Prieto M., Mugica-Vidal R., Muro-Fraguas I., Alba-Elias F., Alvarez-Ordonez A. A review on non-thermal atmospheric plasma for food preservation: Mode of action, determinants of effectiveness, and applications. Front. Microbiol. 2019;10:622. doi: 10.3389/fmicb.2019.00622. PubMed DOI PMC

Arjunan K.P., Friedman G., Fridman A., Clyne A.M. Non-thermal dielectric barrier discharge plasma induces angiogenesis through reactive oxygen species. J. R. Soc. Interface. 2012;9:147–157. doi: 10.1098/rsif.2011.0220. PubMed DOI PMC

Bekeschus S., Schmidt A., Weltmann K.D., von Woedtke T. The plasma jet kINPen—A powerful tool for wound healing. Clin. Plasma Med. 2016;4:19–28. doi: 10.1016/j.cpme.2016.01.001. DOI

Weltmann K.D., von Woedtke T. Plasma medicine-current state of research and medical application. Plasma Phys. Control. Fusion. 2017;59:014031. doi: 10.1088/0741-3335/59/1/014031. DOI

Isbary G., Morfill G., Schmidt H.U., Georgi M., Ramrath K., Heinlin J., Karrer S., Landthaler M., Shimizu T., Steffes B., et al. A first prospective randomized controlled trial to decrease bacterial load using cold atmospheric argon plasma on chronic wounds in patients. Br. J. Dermatol. 2010;163:78–82. doi: 10.1111/j.1365-2133.2010.09744.x. PubMed DOI

Isbary G., Heinlin J., Shimizu T., Zimmermann J.L., Morfill G., Schmidt H.U., Monetti R., Steffes B., Bunk W., Li Y., et al. Successful and safe use of 2 min cold atmospheric argon plasma in chronic wounds: Results of a randomized controlled trial. Br. J. Dermatol. 2012;167:404–410. doi: 10.1111/j.1365-2133.2012.10923.x. PubMed DOI PMC

Heinlin J., Zimmermann J.L., Zeman F., Bunk W., Isbary G., Landthaler M., Maisch T., Monetti R., Morfill G., Shimizu T., et al. Randomized placebo-controlled human pilot study of cold atmospheric argon plasma on skin graft donor sites. Wound Repair Regen. 2013;21:800–807. doi: 10.1111/wrr.12078. PubMed DOI

Daeschlein G., Napp M., Lutze S., Arnold A., von Podewils S., Guembel D., Junger M. Skin and wound decontamination of multidrug-resistant bacteria by cold atmospheric plasma coagulation. J. Dtsch. Dermatol. Ges. 2015;13:143–150. doi: 10.1111/ddg.12559. PubMed DOI

Von Woedtke T., Metelmann H.R., Weltmann K.D. Clinical plasma medicine: State and perspectives of in vivo application of cold atmospheric plasma. Contrib. Plasma Phys. 2014;54:104–117. doi: 10.1002/ctpp.201310068. DOI

Von Woedtke T., Reuter S., Masur K., Weltmann K.D. Plasmas for medicine. Phys. Rep. 2013;530:291–320. doi: 10.1016/j.physrep.2013.05.005. DOI

Heinlin J., Isbary G., Stolz W., Morfill G., Landthaler M., Shimizu T., Steffes B., Nosenko T., Zimmermann J., Karrer S. Plasma applications in medicine with a special focus on dermatology. J. Eur. Acad. Dermatol. Venereol. 2011;25:1–11. doi: 10.1111/j.1468-3083.2010.03702.x. PubMed DOI

Lunov O. Plasma will. Br. J. Dermatol. 2016;174:486–487. doi: 10.1111/bjd.14428. PubMed DOI

Lu X., Naidis G.V., Laroussi M., Reuter S., Graves D.B., Ostrikov K. Reactive species in non-equilibrium atmospheric-pressure plasmas: Generation, transport, and biological effects. Phys. Rep. 2016;630:1–84. doi: 10.1016/j.physrep.2016.03.003. DOI

Ishaq M., Evans M.M., Ostrikov K.K. Effect of atmospheric gas plasmas on cancer cell signaling. Int. J. Cancer. 2014;134:1517–1528. doi: 10.1002/ijc.28323. PubMed DOI

Jang J.Y., Hong Y.J., Lim J., Choi J.S., Choi E.H., Kang S., Rhim H. Cold atmospheric plasma (CAP), a novel physicochemical source, induces neural differentiation through cross-talk between the specific RONS cascade and Trk/Ras/ERK signaling pathway. Biomaterials. 2018;156:258–273. doi: 10.1016/j.biomaterials.2017.11.045. PubMed DOI

Privat-Maldonado A., Schmidt A., Lin A., Weltmann K.D., Wende K., Bogaerts A., Bekeschus S. ROS from physical plasmas: Redox chemistry for biomedical therapy. Oxid. Med. Cell. Longev. 2019;2019:9062098. doi: 10.1155/2019/9062098. PubMed DOI PMC

Smolkova B., Lunova M., Lynnyk A., Uzhytchak M., Churpita O., Jirsa M., Kubinova S., Lunov O., Dejneka A. Non-thermal plasma, as a new physicochemical source, to induce redox imbalance and subsequent cell death in liver cancer cell lines. Cell. Physiol. Biochem. 2019;52:119–140. PubMed

Giorgio M., Trinei M., Migliaccio E., Pelicci P.G. Hydrogen peroxide: A metabolic by-product or a common mediator of ageing signals? Nat. Rev. Mol. Cell Biol. 2007;8:722–728. doi: 10.1038/nrm2240. PubMed DOI

Reth M. Hydrogen peroxide as second messenger in lymphocyte activation. Nat. Immunol. 2002;3:1129–1134. doi: 10.1038/ni1202-1129. PubMed DOI

Holmstrom K.M., Finkel T. Cellular mechanisms and physiological consequences of redox-dependent signalling. Nat. Rev. Mol. Cell Biol. 2014;15:411–421. doi: 10.1038/nrm3801. PubMed DOI

Schieber M., Chandel N.S. ROS function in redox signaling and oxidative stress. Curr. Biol. 2014;24:R453–R462. doi: 10.1016/j.cub.2014.03.034. PubMed DOI PMC

D’Autreaux B., Toledano M.B. ROS as signalling molecules: Mechanisms that generate specificity in ROS homeostasis. Nat. Rev. Mol. Cell Biol. 2007;8:813–824. doi: 10.1038/nrm2256. PubMed DOI

Mittler R., Vanderauwera S., Suzuki N., Miller G., Tognetti V.B., Vandepoele K., Gollery M., Shulaev V., Van Breusegem F. ROS signaling: The new wave? Trends Plant. Sci. 2011;16:300–309. doi: 10.1016/j.tplants.2011.03.007. PubMed DOI

Nathan C., Cunningham-Bussel A. Beyond oxidative stress: An immunologist’s guide to reactive oxygen species. Nat. Rev. Immunol. 2013;13:349–361. doi: 10.1038/nri3423. PubMed DOI PMC

Kong M.G., Kroesen G., Morfill G., Nosenko T., Shimizu T., van Dijk J., Zimmermann J.L. Plasma medicine: An introductory review. New J. Phys. 2009;11:115012. doi: 10.1088/1367-2630/11/11/115012. DOI

Bekeschus S., Clemen R., Niessner F., Sagwal S.K., Freund E., Schmidt A. Medical gas plasma jet technology targets murine melanoma in an immunogenic fashion. Adv. Sci. 2020;7:1903438. doi: 10.1002/advs.201903438. PubMed DOI PMC

Lin A.G., Xiang B., Merlino D.J., Baybutt T.R., Sahu J., Fridman A., Snook A.E., Miller V. Non-thermal plasma induces immunogenic cell death in vivo in murine CT26 colorectal tumors. Oncoimmunology. 2018;7:e1484978. doi: 10.1080/2162402X.2018.1484978. PubMed DOI PMC

Lin A., Gorbanev Y., De Backer J., Van Loenhout J., Van Boxem W., Lemiere F., Cos P., Dewilde S., Smits E., Bogaerts A. Non-thermal plasma as a unique delivery system of short-lived reactive oxygen and nitrogen species for immunogenic cell death in melanoma cells. Adv. Sci. 2019;6:1802062. doi: 10.1002/advs.201802062. PubMed DOI PMC

Fanelli D., Costas R., Lariviere V. Misconduct policies, academic culture and career stage, not gender or pressures to publish, affect scientific integrity. PLoS ONE. 2015;10:e0127556. doi: 10.1371/journal.pone.0127556. PubMed DOI PMC

Morrison S.J. Time to do something about reproducibility. eLife. 2014;3:e03981. doi: 10.7554/eLife.03981. PubMed DOI PMC

Stern A.M., Casadevall A., Steen R.G., Fang F.C. Financial costs and personal consequences of research misconduct resulting in retracted publications. eLife. 2014;3:e02956. doi: 10.7554/eLife.02956. PubMed DOI PMC

Mechanism matters. Nat. Med. 2010;16:347. doi: 10.1038/nm0410-347. PubMed DOI

Ehrenstein M.R., Mauri C. If the treatment works, do we need to know why?: The promise of immunotherapy for experimental medicine. J. Exp. Med. 2007;204:2249–2252. doi: 10.1084/jem.20071737. PubMed DOI PMC

Isbary G., Shimizu T., Li Y.F., Stolz W., Thomas H.M., Morfill G.E., Zimmermann J.L. Cold atmospheric plasma devices for medical issues. Expert Rev. Med. Devices. 2013;10:367–377. doi: 10.1586/erd.13.4. PubMed DOI

Fridman G., Friedman G., Gutsol A., Shekhter A.B., Vasilets V.N., Fridman A. Applied plasma medicine. Plasma Process. Polym. 2008;5:503–533. doi: 10.1002/ppap.200700154. DOI

Lu X., Laroussi M., Puech V. On atmospheric-pressure non-equilibrium plasma jets and plasma bullets. Plasma Sources Sci. Technol. 2012;21:034005. doi: 10.1088/0963-0252/21/3/034005. DOI

Ehlbeck J., Schnabel U., Polak M., Winter J., von Woedtke T., Brandenburg R., von dem Hagen T., Weltmann K.D. Low temperature atmospheric pressure plasma sources for microbial decontamination. J. Phys. D Appl. Phys. 2011;44:013002. doi: 10.1088/0022-3727/44/1/013002. DOI

Fridman G., Peddinghaus M., Ayan H., Fridman A., Balasubramanian M., Gutsol A., Brooks A., Friedman G. Blood coagulation and living tissue sterilization by floating-electrode dielectric barrier discharge in air. Plasma Chem. Plasma Process. 2006;26:425–442. doi: 10.1007/s11090-006-9024-4. DOI

Dobrynin D., Fridman G., Friedman G., Fridman A. Physical and biological mechanisms of direct plasma interaction with living tissue. New J. Phys. 2009;11:115020. doi: 10.1088/1367-2630/11/11/115020. DOI

Al-Abduly A., Christensen P. An in situ and downstream study of non-thermal plasma chemistry in an air fed dielectric barrier discharge (DBD) Plasma Sources Sci. Technol. 2015;24:065006. doi: 10.1088/0963-0252/24/6/065006. DOI

Attri P., Kim Y.H., Park D.H., Park J.H., Hong Y.J., Uhm H.S., Kim K.N., Fridman A., Choi E.H. Generation mechanism of hydroxyl radical species and its lifetime prediction during the plasma-initiated ultraviolet (UV) photolysis. Sci. Rep. 2015;5:9332. doi: 10.1038/srep09332. PubMed DOI PMC

Rumbach P., Witzke M., Sankaran R.M., Go D.B. Decoupling interfacial reactions between plasmas and liquids: Charge transfer vs. plasma neutral reactions. J. Am. Chem. Soc. 2013;135:16264–16267. doi: 10.1021/ja407149y. PubMed DOI

Jablonowski H., von Woedtke T. Research on plasma medicine-relevant plasma–liquid interaction: What happened in the past five years? Clin. Plasma Med. 2015;3:42–52. doi: 10.1016/j.cpme.2015.11.003. DOI

Girard P.M., Arbabian A., Fleury M., Bauville G., Puech V., Dutreix M., Sousa J.S. Synergistic effect of H2O2 and NO2 in cell death induced by cold atmospheric He plasma. Sci. Rep. 2016;6:29098. doi: 10.1038/srep29098. PubMed DOI PMC

Shiraiwa M., Sosedova Y., Rouviere A., Yang H., Zhang Y., Abbatt J.P., Ammann M., Poschl U. The role of long-lived reactive oxygen intermediates in the reaction of ozone with aerosol particles. Nat. Chem. 2011;3:291–295. doi: 10.1038/nchem.988. PubMed DOI

Endre J.S., James W.B., Robert D.S. A ‘tissue model’ to study the plasma delivery of reactive oxygen species. J. Phys. D Appl. Phys. 2014;47:152002.

Lackmann J.W., Wende K., Verlackt C., Golda J., Volzke J., Kogelheide F., Held J., Bekeschus S., Bogaerts A., Schulz-von der Gathen V., et al. Chemical fingerprints of cold physical plasmas—An experimental and computational study using cysteine as tracer compound. Sci. Rep. 2018;8:7736. doi: 10.1038/s41598-018-25937-0. PubMed DOI PMC

Arndt S., Unger P., Berneburg M., Bosserhoff A.K., Karrer S. Cold atmospheric plasma (CAP) activates angiogenesis-related molecules in skin keratinocytes, fibroblasts and endothelial cells and improves wound angiogenesis in an autocrine and paracrine mode. J. Dermatol. Sci. 2018;89:181–190. doi: 10.1016/j.jdermsci.2017.11.008. PubMed DOI

Kalghatgi S., Friedman G., Fridman A., Clyne A.M. Endothelial cell proliferation is enhanced by low dose non-thermal plasma through fibroblast growth factor-2 release. Ann. Biomed. Eng. 2010;38:748–757. doi: 10.1007/s10439-009-9868-x. PubMed DOI

Kalghatgi S., Kelly C.M., Cerchar E., Torabi B., Alekseev O., Fridman A., Friedman G., Azizkhan-Clifford J. Effects of non-thermal plasma on mammalian cells. PLoS ONE. 2011;6:e16270. doi: 10.1371/journal.pone.0016270. PubMed DOI PMC

Gweon B., Kim D., Kim D.B., Jung H., Choe W., Shin J.H. Plasma effects on subcellular structures. Appl. Phys. Lett. 2010;96:101501. doi: 10.1063/1.3352316. DOI

Kim G.J., Kim W., Kim K.T., Lee J.K. DNA damage and mitochondria dysfunction in cell apoptosis induced by nonthermal air plasma. Appl. Phys. Lett. 2010;96:021502. doi: 10.1063/1.3292206. DOI

Ahn H.J., Kim K.I., Hoan N.N., Kim C.H., Moon E., Choi K.S., Yang S.S., Lee J.S. Targeting cancer cells with reactive oxygen and nitrogen species generated by atmospheric-pressure air plasma. PLoS ONE. 2014;9:e86173. doi: 10.1371/journal.pone.0086173. PubMed DOI PMC

Ahn H.J., Kim K.I., Kim G., Moon E., Yang S.S., Lee J.S. Atmospheric-pressure plasma jet induces apoptosis involving mitochondria via generation of free radicals. PLoS ONE. 2011;6:e28154. doi: 10.1371/journal.pone.0028154. PubMed DOI PMC

Lunov O., Zablotskii V., Churpita O., Lunova M., Jirsa M., Dejneka A., Kubinova S. Chemically different non-thermal plasmas target distinct cell death pathways. Sci. Rep. 2017;7:600. doi: 10.1038/s41598-017-00689-5. PubMed DOI PMC

Lunov O., Zablotskii V., Churpita O., Jaeger A., Polivka L., Sykova E., Terebova N., Kulikov A., Kubinova S., Dejneka A. Towards the understanding of non-thermal air plasma action: Effects on bacteria and fibroblasts. RSC Adv. 2016;6:25286–25292. doi: 10.1039/C6RA02368A. DOI

Park J.Y., Park S., Choe W., Yong H.I., Jo C., Kim K. Plasma-functionalized solution: A potent antimicrobial agent for biomedical applications from antibacterial therapeutics to biomaterial surface engineering. ACS Appl. Mater. Interfaces. 2017;9:43470–43477. doi: 10.1021/acsami.7b14276. PubMed DOI

Metelmann H.R., Seebauer C., Miller V., Fridman A., Bauer G., Graves D.B., Pouvesle J.M., Rutkowski R., Schuster M., Bekeschus S., et al. Clinical experience with cold plasma in the treatment of locally advanced head and neck cancer. Clin. Plasma Med. 2018;9:6–13. doi: 10.1016/j.cpme.2017.09.001. DOI

Jablonowski L., Kocher T., Schindler A., Muller K., Dombrowski F., von Woedtke T., Arnold T., Lehmann A., Rupf S., Evert M., et al. Side effects by oral application of atmospheric pressure plasma on the mucosa in mice. PLoS ONE. 2019;14:e0215099. doi: 10.1371/journal.pone.0215099. PubMed DOI PMC

Schuster M., Rutkowski R., Hauschild A., Shojaei R.K., von Woedtke T., Rana A., Bauer G., Metelmann P., Seebauer C. Side effects in cold plasma treatment of advanced oral cancer-clinical data and biological interpretation. Clin. Plasma Med. 2018;10:9–15. doi: 10.1016/j.cpme.2018.04.001. DOI

Coleman J.J., Ferner R.E., Evans S.J. Monitoring for adverse drug reactions. Br. J. Clin. Pharmacol. 2006;61:371–378. doi: 10.1111/j.1365-2125.2006.02596.x. PubMed DOI PMC

Coleman J.J., Pontefract S.K. Adverse drug reactions. Clin. Med. 2016;16:481–485. doi: 10.7861/clinmedicine.16-5-481. PubMed DOI PMC

McDowell S.E., Thomas S.K., Coleman J.J., Aronson J.K., Ferner R.E. A practical guide to monitoring for adverse drug reactions during antihypertensive drug therapy. J. R. Soc. Med. 2013;106:87–95. doi: 10.1258/jrsm.2012.120137. PubMed DOI PMC

Arjunan K.P., Sharma V.K., Ptasinska S. Effects of atmospheric pressure plasmas on isolated and cellular DNA-a review. Int. J. Mol. Sci. 2015;16:2971–3016. doi: 10.3390/ijms16022971. PubMed DOI PMC

Wende K., Bekeschus S., Schmidt A., Jatsch L., Hasse S., Weltmann K.D., Masur K., von Woedtke T. Risk assessment of a cold argon plasma jet in respect to its mutagenicity. Mutat. Res. Genet. Toxicol. Environ. 2016;798–799:48–54. doi: 10.1016/j.mrgentox.2016.02.003. PubMed DOI

Fiers W., Beyaert R., Declercq W., Vandenabeele P. More than one way to die: Apoptosis, necrosis and reactive oxygen damage. Oncogene. 1999;18:7719–7730. doi: 10.1038/sj.onc.1203249. PubMed DOI

Linkermann A., Green D.R. Necroptosis. N. Engl. J. Med. 2014;370:455–465. doi: 10.1056/NEJMra1310050. PubMed DOI PMC

Marino G., Niso-Santano M., Baehrecke E.H., Kroemer G. Self-consumption: The interplay of autophagy and apoptosis. Nat. Rev. Mol. Cell Biol. 2014;15:81–94. doi: 10.1038/nrm3735. PubMed DOI PMC

Temkin V., Karin M. From death receptor to reactive oxygen species and c-Jun N-terminal protein kinase: The receptor-interacting protein 1 odyssey. Immunol. Rev. 2007;220:8–21. doi: 10.1111/j.1600-065X.2007.00560.x. PubMed DOI

Jin J., Sklar G.E., Min Sen Oh V., Chuen Li S. Factors affecting therapeutic compliance: A review from the patient’s perspective. Ther. Clin. Risk Manag. 2008;4:269–286. PubMed PMC

Ulrich C., Kluschke F., Patzelt A., Vandersee S., Czaika V.A., Richter H., Bob A., von Hutten J., Painsi C., Hugel R., et al. Clinical use of cold atmospheric pressure argon plasma in chronic leg ulcers: A pilot study. J. Wound Care. 2015;24:196–203. doi: 10.12968/jowc.2015.24.5.196. PubMed DOI

Emmert S., Brehmer F., Hänßle H., Helmke A., Mertens N., Ahmed R., Simon D., Wandke D., Maus-Friedrichs W., Däschlein G., et al. Atmospheric pressure plasma in dermatology: Ulcus treatment and much more. Clin. Plasma Med. 2013;1:24–29. doi: 10.1016/j.cpme.2012.11.002. DOI

Isbary G., Shimizu T., Zimmermann J.L., Heinlin J., Al-Zaabi S., Rechfeld M., Morfill G.E., Karrer S., Stolz W. Randomized placebo-controlled clinical trial showed cold atmospheric argon plasma relieved acute pain and accelerated healing in herpes zoster. Clin. Plasma Med. 2014;2:50–55. doi: 10.1016/j.cpme.2014.07.001. DOI

Klebes M., Lademann J., Philipp S., Ulrich C., Patzelt A., Ulmer M., Kluschke F., Kramer A., Weltmann K.D., Sterry W., et al. Effects of tissue-tolerable plasma on psoriasis vulgaris treatment compared to conventional local treatment: A pilot study. Clin. Plasma Med. 2014;2:22–27. doi: 10.1016/j.cpme.2013.11.002. DOI

Isbary G., Zimmermann J.L., Shimizu T., Li Y.F., Morfill G.E., Thomas H.M., Steffes B., Heinlin J., Karrer S., Stolz W. Non-thermal plasma—More than five years of clinical experience. Clin. Plasma Med. 2013;1:19–23. doi: 10.1016/j.cpme.2012.11.001. DOI

Freund E., Liedtke K.R., van der Linde J., Metelmann H.R., Heidecke C.D., Partecke L.I., Bekeschus S. Physical plasma-treated saline promotes an immunogenic phenotype in CT26 colon cancer cells in vitro and in vivo. Sci. Rep. 2019;9:634. doi: 10.1038/s41598-018-37169-3. PubMed DOI PMC

Dickersin K., Straus S.E., Bero L.A. Evidence based medicine: Increasing, not dictating, choice. BMJ. 2007;334(Suppl. 1):s10. doi: 10.1136/bmj.39062.639444.94. PubMed DOI

Karagiannis T. The importance of applying evidence-based medicine in clinical practice. In: Papademetriou V., Andreadis E.A., Geladari C., editors. Management of Hypertension: Current Practice and the Application of Landmark Trials. Springer International Publishing; Cham, Switzerland: 2019. pp. 3–17. DOI

Djulbegovic B., Guyatt G.H. Progress in evidence-based medicine: A quarter century on. Lancet. 2017;390:415–423. doi: 10.1016/S0140-6736(16)31592-6. PubMed DOI

Ben-Shlomo Y. Evidence based medicine: Does it make a difference? Numerophobia may be a problem in adopting evidence based medicine. BMJ. 2005;330:93. PubMed PMC

Rosenberg W., Donald A. Evidence based medicine: An approach to clinical problem-solving. BMJ. 1995;310:1122–1126. doi: 10.1136/bmj.310.6987.1122. PubMed DOI PMC

Sabri A.A., Qayyum M.A. The problem of evidence-based medicine in developing countries. CMAJ. 2006;175:62. doi: 10.1503/cmaj.1060108. PubMed DOI PMC

Woolf S.H., Grol R., Hutchinson A., Eccles M., Grimshaw J. Clinical guidelines: Potential benefits, limitations, and harms of clinical guidelines. BMJ. 1999;318:527–530. doi: 10.1136/bmj.318.7182.527. PubMed DOI PMC

Kredo T., Bernhardsson S., Machingaidze S., Young T., Louw Q., Ochodo E., Grimmer K. Guide to clinical practice guidelines: The current state of play. Int. J. Qual. Health Care. 2016;28:122–128. doi: 10.1093/intqhc/mzv115. PubMed DOI PMC

Ho P.M., Peterson P.N., Masoudi F.A. Evaluating the evidence—Is there a rigid hierarchy? Circulation. 2008;118:1675–1684. doi: 10.1161/CIRCULATIONAHA.107.721357. PubMed DOI

Yetley E.A., MacFarlane A.J., Greene-Finestone L.S., Garza C., Ard J.D., Atkinson S.A., Bier D.M., Carriquiry A.L., Harlan W.R., Hattis D., et al. Options for basing Dietary Reference Intakes (DRIs) on chronic disease endpoints: Report from a joint US-/Canadian-sponsored working group. Am. J. Clin. Nutr. 2017;105:249S–285S. doi: 10.3945/ajcn.116.139097. PubMed DOI PMC

Atkins D., Briss P.A., Eccles M., Flottorp S., Guyatt G.H., Harbour R.T., Hill S., Jaeschke R., Liberati A., Magrini N., et al. Systems for grading the quality of evidence and the strength of recommendations II: Pilot study of a new system. BMC Health Serv. Res. 2005;5:25. doi: 10.1186/1472-6963-5-25. PubMed DOI PMC

Harbour R., Miller J. A new system for grading recommendations in evidence based guidelines. BMJ. 2001;323:334–336. doi: 10.1136/bmj.323.7308.334. PubMed DOI PMC

Haidich A.B. Meta-analysis in medical research. Hippokratia. 2010;14:29–37. PubMed PMC

Hartling L., Dryden D.M., Guthrie A., Muise M., Vandermeer B., Donovan L. Benefits and harms of treating gestational diabetes mellitus: A systematic review and meta-analysis for the U.S. Preventive Services Task Force and the National Institutes of Health Office of Medical Applications of Research. Ann. Intern. Med. 2013;159:123–129. doi: 10.7326/0003-4819-159-2-201307160-00661. PubMed DOI

Mbuagbaw L., Wiysonge C.S., Nsagha D.S., Ongolo-Zogo P., Pantoja T. An introduction to systematic reviews and meta-analysis: A workshop report on promoting evidence based medical practice through capacity building in research synthesis. Pan Afr. Med. J. 2011;8:15. doi: 10.4314/pamj.v8i1.71066. PubMed DOI PMC

O’Rourke K., Detsky A.S. Meta-analysis in medical research: Strong encouragement for higher quality in individual research efforts. J. Clin. Epidemiol. 1989;42:1021–1024. doi: 10.1016/0895-4356(89)90168-6. PubMed DOI

Wende K., von Woedtke T., Weltmann K.D., Bekeschus S. Chemistry and biochemistry of cold physical plasma derived reactive species in liquids. Biol. Chem. 2018;400:19–38. doi: 10.1515/hsz-2018-0242. PubMed DOI

Medzhitov R., Janeway C., Jr. Innate immunity. N. Engl. J. Med. 2000;343:338–344. doi: 10.1056/NEJM200008033430506. PubMed DOI

Bonilla F.A., Oettgen H.C. Adaptive immunity. J. Allergy Clin. Immunol. 2010;125:S33–S40. doi: 10.1016/j.jaci.2009.09.017. PubMed DOI

Zanoni I., Ostuni R., Marek L.R., Barresi S., Barbalat R., Barton G.M., Granucci F., Kagan J.C. CD14 controls the LPS-induced endocytosis of Toll-like receptor 4. Cell. 2011;147:868–880. doi: 10.1016/j.cell.2011.09.051. PubMed DOI PMC

Baran C.P., Zeigler M.M., Tridandapani S., Marsh C.B. The role of ROS and RNS in regulating life and death of blood monocytes. Curr. Pharm. Des. 2004;10:855–866. doi: 10.2174/1381612043452866. PubMed DOI

Murray P.J. Macrophage Polarization. Annu. Rev. Physiol. 2017;79:541–566. doi: 10.1146/annurev-physiol-022516-034339. PubMed DOI

McWhorter F.Y., Davis C.T., Liu W.F. Physical and mechanical regulation of macrophage phenotype and function. Cell. Mol. Life Sci. 2015;72:1303–1316. doi: 10.1007/s00018-014-1796-8. PubMed DOI PMC

Castano A.P., Mroz P., Hamblin M.R. Photodynamic therapy and anti-tumour immunity. Nat. Rev. Cancer. 2006;6:535–545. doi: 10.1038/nrc1894. PubMed DOI PMC

Kaushik N.K., Kaushik N., Min B., Choi K.H., Hong Y.J., Miller V., Fridman A., Choi E.H. Cytotoxic macrophage-released tumour necrosis factor-alpha (TNF-alpha) as a killing mechanism for cancer cell death after cold plasma activation. J. Phys. D Appl. Phys. 2016;49:084001. doi: 10.1088/0022-3727/49/8/084001. DOI

Freund E., Moritz J., Stope M., Seebauer C., Schmidt A., Bekeschus S. Plasma-derived reactive species shape a differentiation profile in human monocytes. Appl. Sci. 2019;9:2530. doi: 10.3390/app9122530. DOI

Bekeschus S., Scherwietes L., Freund E., Liedtke K.R., Hackbarth C., von Woedtke T., Partecke L.I. Plasma-treated medium tunes the inflammatory profile in murine bone marrow-derived macrophages. Clin. Plasma Med. 2018;11:1–9. doi: 10.1016/j.cpme.2018.06.001. DOI

Bekeschus S., Schmidt A., Bethge L., Masur K., von Woedtke T., Hasse S., Wende K. Redox stimulation of human THP-1 monocytes in response to cold physical plasma. Oxid. Med. Cell. Longev. 2016;2016:5910695. doi: 10.1155/2016/5910695. PubMed DOI PMC

Schmidt A., Rodder K., Hasse S., Masur K., Toups L., Lillig C.H., von Woedtke T., Wende K., Bekeschus S. Redox-regulation of activator protein 1 family members in blood cancer cell lines exposed to cold physical plasma-treated medium. Plasma Process. Polym. 2016;13:1179–1188. doi: 10.1002/ppap.201600090. DOI

Kaushik N., Lee S.J., Choi T.G., Baik K.Y., Uhm H.S., Kim C.H., Kaushik N.K., Choi E.H. Non-thermal plasma with 2-deoxy-D-glucose synergistically induces cell death by targeting glycolysis in blood cancer cells. Sci. Rep. 2015;5:8726. doi: 10.1038/srep08726. PubMed DOI PMC

Bekeschus S., Winterbourn C.C., Kolata J., Masur K., Hasse S., Broker B.M., Parker H.A. Neutrophil extracellular trap formation is elicited in response to cold physical plasma. J. Leukocyte Biol. 2016;100:791–799. doi: 10.1189/jlb.3A0415-165RR. PubMed DOI

Lin A., Truong B., Patel S., Kaushik N., Choi E.H., Fridman G., Fridman A., Miller V. Nanosecond-pulsed DBD plasma-generated reactive oxygen species trigger immunogenic cell death in A549 lung carcinoma cells through intracellular oxidative stress. Int. J. Mol. Sci. 2017;18:966. doi: 10.3390/ijms18050966. PubMed DOI PMC

Lin A., Truong B., Pappas A., Kirifides L., Oubarri A., Chen S., Lin S., Dobrynin D., Fridman G., Fridman A., et al. Uniform nanosecond pulsed dielectric barrier discharge plasma enhances anti-tumor effects by induction of immunogenic cell death in tumors and stimulation of macrophages. Plasma Process. Polym. 2015;12:1392–1399. doi: 10.1002/ppap.201500139. DOI

Bundscherer L., Wende K., Ottmuller K., Barton A., Schmidt A., Bekeschus S., Hasse S., Weltmann K.D., Masur K., Lindequist U. Impact of non-thermal plasma treatment on MAPK signaling pathways of human immune cell lines. Immunobiology. 2013;218:1248–1255. doi: 10.1016/j.imbio.2013.04.015. PubMed DOI

Turrini E., Laurita R., Stancampiano A., Catanzaro E., Calcabrini C., Maffei F., Gherardi M., Colombo V., Fimognari C. Cold atmospheric plasma induces apoptosis and oxidative stress pathway regulation in T-lymphoblastoid leukemia cells. Oxid. Med. Cell. Longev. 2017;2017:4271065. doi: 10.1155/2017/4271065. PubMed DOI PMC

Bekeschus S., Schütz C.S., Nießner F., Wende K., Weltmann K.-D., Gelbrich N., von Woedtke T., Schmidt A., Stope M.B. Elevated H2AX phosphorylation observed with kINPen plasma treatment is not caused by ROS-mediated DNA damage but is the consequence of apoptosis. Oxid. Med. Cell. Longev. 2019;2019:8535163. doi: 10.1155/2019/8535163. PubMed DOI PMC

Crestale L., Laurita R., Liguori A., Stancampiano A., Talmon M., Bisag A., Gherardi M., Amoruso A., Colombo V., Fresu L.G. Cold atmospheric pressure plasma treatment modulates human monocytes/macrophages responsiveness. Plasma. 2018;1:261–276. doi: 10.3390/plasma1020023. DOI

Rodder K., Moritz J., Miller V., Weltmann K.D., Metelmann H.R., Gandhirajan R., Bekeschus S. Activation of murine immune cells upon co-culture with plasma-treated B16F10 melanoma cells. Appl. Sci. 2019;9:660. doi: 10.3390/app9040660. DOI

Hamid O., Robert C., Daud A., Hodi F.S., Hwu W.J., Kefford R., Wolchok J.D., Hersey P., Joseph R.W., Weber J.S., et al. Safety and tumor responses with lambrolizumab (anti-PD-1) in melanoma. N. Engl. J. Med. 2013;369:134–144. doi: 10.1056/NEJMoa1305133. PubMed DOI PMC

Hodi F.S., O’Day S.J., McDermott D.F., Weber R.W., Sosman J.A., Haanen J.B., Gonzalez R., Robert C., Schadendorf D., Hassel J.C., et al. Improved survival with ipilimumab in patients with metastatic melanoma. N. Engl. J. Med. 2010;363:711–723. doi: 10.1056/NEJMoa1003466. PubMed DOI PMC

Bundscherer L., Bekeschus S., Tresp H., Hasse S., Reuter S., Weltmann K.-D., Lindequist U., Masur K. Viability of human blood leukocytes compared with their respective cell lines after plasma treatment. Plasma Med. 2013;3:71–80. doi: 10.1615/PlasmaMed.2013008538. DOI

Zuo L., Zhou T., Pannell B.K., Ziegler A.C., Best T.M. Biological and physiological role of reactive oxygen species—The good, the bad and the ugly. Acta Physiol. 2015;214:329–348. doi: 10.1111/apha.12515. PubMed DOI

Trachootham D., Alexandre J., Huang P. Targeting cancer cells by ROS-mediated mechanisms: A radical therapeutic approach? Nat. Rev. Drug Discov. 2009;8:579–591. doi: 10.1038/nrd2803. PubMed DOI

Van Loenhout J., Flieswasser T., Freire Boullosa L., De Waele J., Van Audenaerde J., Marcq E., Jacobs J., Lin A., Lion E., Dewitte H., et al. Cold atmospheric plasma-treated PBS eliminates immunosuppressive pancreatic stellate cells and induces immunogenic cell death of pancreatic cancer cells. Cancers. 2019;11:1597. doi: 10.3390/cancers11101597. PubMed DOI PMC

Azzariti A., Iacobazzi R.M., Di Fonte R., Porcelli L., Gristina R., Favia P., Fracassi F., Trizio I., Silvestris N., Guida G., et al. Plasma-activated medium triggers cell death and the presentation of immune activating danger signals in melanoma and pancreatic cancer cells. Sci. Rep. 2019;9:4099. doi: 10.1038/s41598-019-40637-z. PubMed DOI PMC

Galluzzi L., Vitale I., Warren S., Adjemian S., Agostinis P., Martinez A.B., Chan T.A., Coukos G., Demaria S., Deutsch E., et al. Consensus guidelines for the definition, detection and interpretation of immunogenic cell death. J. Immunother. Cancer. 2020;8:e000337. doi: 10.1136/jitc-2019-000337. PubMed DOI PMC

Kepp O., Senovilla L., Vitale I., Vacchelli E., Adjemian S., Agostinis P., Apetoh L., Aranda F., Barnaba V., Bloy N., et al. Consensus guidelines for the detection of immunogenic cell death. Oncoimmunology. 2014;3:e955691. doi: 10.4161/21624011.2014.955691. PubMed DOI PMC

Liedtke K.R., Freund E., Hackbarth C., Heidecke C.D., Partecke L.I., Bekeschus S. A myeloid and lymphoid infiltrate in murine pancreatic tumors exposed to plasma-treated medium. Clin. Plasma Med. 2018;11:10–17. doi: 10.1016/j.cpme.2018.07.001. DOI

Liedtke K.R., Bekeschus S., Kaeding A., Hackbarth C., Kuehn J.P., Heidecke C.D., von Bernstorff W., von Woedtke T., Partecke L.I. Non-thermal plasma-treated solution demonstrates antitumor activity against pancreatic cancer cells in vitro and in vivo. Sci. Rep. 2017;7:8319. doi: 10.1038/s41598-017-08560-3. PubMed DOI PMC

Mizuno K., Yonetamari K., Shirakawa Y., Akiyama T., Ono R. Anti-tumor immune response induced by nanosecond pulsed streamer discharge in mice. J. Phys. D Appl. Phys. 2017;50:12LT01. doi: 10.1088/1361-6463/aa5dbb. DOI

Lee Y.S., Lee M.H., Kim H.J., Won H.R., Kim C.H. Non-thermal atmospheric plasma ameliorates imiquimod-induced psoriasis-like skin inflammation in mice through inhibition of immune responses and up-regulation of PD-L1 expression. Sci. Rep. 2017;7:15564. doi: 10.1038/s41598-017-15725-7. PubMed DOI PMC

Lee M.H., Lee Y.S., Kim H.J., Han C.H., Kang S.U., Kim C.H. Non-thermal plasma inhibits mast cell activation and ameliorates allergic skin inflammatory diseases in NC/Nga mice. Sci. Rep. 2019;9:13510. doi: 10.1038/s41598-019-49938-9. PubMed DOI PMC

Ioannidis J.P.A. Why most published research findings are false. PLoS Med. 2005;2:696–701. doi: 10.1371/journal.pmed.0020124. PubMed DOI PMC

Ioannidis J.P.A. Why most published research findings are false: Author’s reply to Goodman and Greenland. PLoS Med. 2007;4:1132–1133. doi: 10.1371/journal.pmed.0040215. PubMed DOI PMC

Baker M. 1500 scientists lift the lid on reproducibility. Nature. 2016;533:452–454. doi: 10.1038/533452a. PubMed DOI

Fang F.C., Steen R.G., Casadevall A. Misconduct accounts for the majority of retracted scientific publications. Proc. Natl. Acad. Sci. USA. 2012;109:17028–17033. doi: 10.1073/pnas.1212247109. PubMed DOI PMC

Harris R. Rigor Mortis: How Sloppy Science Creates Worthless Cures, Crushes Hope, and Wastes Billions. 1st ed. Basic Books; New York, NY, USA: 2017. p. 288.

Begley C.G., Ellis L.M. Drug development: Raise standards for preclinical cancer research. Nature. 2012;483:531–533. doi: 10.1038/483531a. PubMed DOI

Freedman L.P., Cockburn I.M., Simcoe T.S. The economics of reproducibility in preclinical research. PLoS Biol. 2015;13:e1002165. doi: 10.1371/journal.pbio.1002165. PubMed DOI PMC

Hines W.C., Su Y., Kuhn I., Polyak K., Bissell M.J. Sorting out the FACS: A devil in the details. Cell Rep. 2014;6:779–781. doi: 10.1016/j.celrep.2014.02.021. PubMed DOI

Abrink M., Gobl A.E., Huang R., Nilsson K., Hellman L. Human cell lines U-937, THP-1 and Mono Mac 6 represent relatively immature cells of the monocyte-macrophage cell lineage. Leukemia. 1994;8:1579–1584. PubMed

Xia T., Kovochich M., Brant J., Hotze M., Sempf J., Oberley T., Sioutas C., Yeh J.I., Wiesner M.R., Nel A.E. Comparison of the abilities of ambient and manufactured nanoparticles to induce cellular toxicity according to an oxidative stress paradigm. Nano Lett. 2006;6:1794–1807. doi: 10.1021/nl061025k. PubMed DOI

Xia T., Kovochich M., Liong M., Zink J.I., Nel A.E. Cationic polystyrene nanosphere toxicity depends on cell-specific endocytic and mitochondrial injury pathways. ACS Nano. 2008;2:85–96. doi: 10.1021/nn700256c. PubMed DOI

Schwende H., Fitzke E., Ambs P., Dieter P. Differences in the state of differentiation of THP-1 cells induced by phorbol ester and 1,25-dihydroxyvitamin D3. J. Leukoc. Biol. 1996;59:555–561. doi: 10.1002/jlb.59.4.555. PubMed DOI

Daigneault M., Preston J.A., Marriott H.M., Whyte M.K., Dockrell D.H. The identification of markers of macrophage differentiation in PMA-stimulated THP-1 cells and monocyte-derived macrophages. PLoS ONE. 2010;5:e8668. doi: 10.1371/journal.pone.0008668. PubMed DOI PMC

Kohro T., Tanaka T., Murakami T., Wada Y., Aburatani H., Hamakubo T., Kodama T. A comparison of differences in the gene expression profiles of phorbol 12-myristate 13-acetate differentiated THP-1 cells and human monocyte-derived macrophage. J. Atheroscler. Thromb. 2004;11:88–97. doi: 10.5551/jat.11.88. PubMed DOI

Prinz F., Schlange T., Asadullah K. Believe it or not: How much can we rely on published data on potential drug targets? Nat. Rev. Drug Discov. 2011;10:712. doi: 10.1038/nrd3439-c1. PubMed DOI

Swinney D.C. Biochemical mechanisms of drug action: What does it take for success? Nat. Rev. Drug Discov. 2004;3:801–808. doi: 10.1038/nrd1500. PubMed DOI

Chernajovsky Y. The importance of understanding the molecular mechanisms of resistance to biologics. Rheumatology. 2012;51:397–398. doi: 10.1093/rheumatology/ker313. PubMed DOI

Scannell J.W., Blanckley A., Boldon H., Warrington B. Diagnosing the decline in pharmaceutical R&D efficiency. Nat. Rev. Drug Discov. 2012;11:191–200. PubMed

Bae Y.H., Park K. Targeted drug delivery to tumors: Myths, reality and possibility. J. Control. Release. 2011;153:198–205. doi: 10.1016/j.jconrel.2011.06.001. PubMed DOI PMC

The interactions between DNA nanostructures and cells: A critical overview from a cell biology perspective