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A rigorous biochemical analysis of interactions between non-thermal plasmas (NTPs) and living cells has become an important research topic, due to recent developments in biomedical applications of non-thermal plasmas. Here, we decouple distinct cell death pathways targeted by chemically different NTPs. We show that helium NTP cells treatment, results in necrosome formation and necroptosis execution, whereas air NTP leads to mTOR activation and autophagy inhibition, that induces mTOR-related necrosis. On the contrary, ozone (abundant component of air NTP) treatment alone, exhibited the highest levels of reactive oxygen species production leading to CypD-related necrosis via the mitochondrial permeability transition. Our findings offer a novel insight into plasma-induced cellular responses, and reveal distinct cell death pathways triggered by NTPs.

Non-thermal plasma research has put a growing focus on the bacteria inactivation problem. In this article we show how low temperature atmospheric plasma destroys Gram-positive and Gram-negative bacteria and discuss the mechanisms of plasma bactericidal effects and a discrepancy in the plasma-triggered effects and ozone (which is a component of air plasma gases). The proven safety of air plasma for fibroblasts is a key factor for the medical applications of plasma.

Background/aims Alteration of cancer cell redox status has been recognized as a promising therapeutic implication. In recent years, the emerged field of non-thermal plasma (NTP) has shown considerable promise in various biomedical applications, including cancer therapy. However, understanding the molecular mechanisms procuring cellular responses remains incomplete. Thus, the aim of this study was a rigorous biochemical analysis of interactions between NTP and liver cancer cells. Methods The concept was validated using three different cell lines. We provide several distinct lines of evidence to support our findings; we use various methods (epifluorescent and confocal microscopy, clonogenic and cytotoxicity assays, Western blotting, pharmacological inhibition studies, etc.). Results We assessed the influence of NTP on three human liver cancer cell lines (Huh7, Alexander and HepG2). NTP treatment resulted in higher anti-proliferative effect against Alexander and Huh7 relative to HepG2. Our data clearly showed that the NTP-mediated alternation of mitochondrial membrane potential and dynamics led to ROS-mediated apoptosis in Huh7 and Alexander cells. Interestingly, plasma treatment resulted in p53 down-regulation in Huh7 cells. High levels of Bcl-2 protein expression in HepG2 resulted in their resistance in response to oxidative stress- mediated by plasma. Conclusion We show thoroughly time- and dose-dependent kinetics of ROS accumulation in HCC cells. Furthermore, we show nuclear compartmentalization of the superoxide anion triggered by NTP. NTP induced apoptotic death in Huh7 liver cancer cells via simultaneous downregulation of mutated p53, pSTAT1 and STAT1. Contrary, hydrogen peroxide treatment results in autophagic cell death. We disclosed detailed mechanisms of NTP-mediated alteration of redox signalling in liver cancer cells.

Non-thermal plasma (NTP) has nonspecific antibacterial effects, and can be applied as an effective tool for the treatment of chronic wounds and other skin pathologies. In this study we analysed the effect of NTP on the healing of the full-thickness acute skin wound model in rats. We utilised a single jet NTP system generating atmospheric pressure air plasma, with ion volume density 5 · 1017 m−3 and gas temperature 30–35 °C. The skin wounds were exposed to three daily plasma treatments for 1 or 2 minutes and were evaluated 3, 7 and 14 days after the wounding by histological and gene expression analysis. NTP treatment significantly enhanced epithelization and wound contraction on day 7 when compared to the untreated wounds. Macrophage infiltration into the wound area was not affected by the NTP treatment. Gene expression analysis did not indicate an increased inflammatory reaction or a disruption of the wound healing process; transient enhancement of inflammatory marker upregulation was found after NTP treatment on day 7. In summary, NTP treatment had improved the healing efficacy of acute skin wounds without noticeable side effects and concomitant activation of pro-inflammatory signalling. The obtained results highlight the favourability of plasma applications for wound therapy in clinics.

Cancer recurrence, which is frequently accompanied by chemotherapy, has been a challenge in cancer treatment. Non-thermal plasma (NTP) has been recognized as a promising tool across a vast variety of biomedical applications including as a potential new therapeutic modality for cancer, with the potential of creating novel therapeutic methods. However, its mechanism of action remains unclear. In this study we examined the influence of non-thermal air-plasma on human hepatocellular carcinoma cell lines. We show how air non-thermal plasma induces cell death in two hepatocellular carcinoma cell lines (HepG2 and Huh7) via the formation of multiple intracellular reactive oxygen/nitrogen species. Interestingly, NTP demonstrated greater selective anti-proliferative activity against Huh7 cells relative to HepG2. Our results showed a discrepancy in the superoxide accumulation and lysosomal activity in response to plasma in these cell lines, suggesting that plasma-triggered signaling cascades might be grossly different between HepG2 and Huh7. Additionally, NTP induced distinct reactive oxygen species compartmentalization in two different hepatocellular carcinoma cell lines. In Huh7 plasma treatment resulted in nuclear accumulation of superoxide, whereas in HepG2 superoxide was diffusively distributed in cytosol. Our findings offer novel insight into plasma-induced cellular responses, and provide a basis for better controlled biomedical applications.

Direct interactions of plasma matter with living cells and tissues can dramatically affect their functionality, initiating many important effects from cancer elimination to bacteria deactivation. However, the physical mechanisms and biochemical pathways underlying the effects of non-thermal plasma on bacteria and cell fate have still not been fully explored. Here, we report on the molecular mechanisms of non-thermal plasma-induced bacteria inactivation in both Gram-positive and Gram-negative strains. We demonstrate that depending on the exposure time plasma induces either direct physical destruction of bacteria or triggers programmed cell death (PCD) that exhibits characteristic features of apoptosis. The interplay between physical disruption and PCD is on the one hand driven by physical plasma parameters, and on the other hand by biological and physical properties of bacteria. The explored possibilities of the tuneable bacteria deactivation provide a basis for the development of advanced plasma-based therapies. To a great extent, our study opens new possibilities for controlled non-thermal plasma interactions with living systems.

Non-thermal plasma has been recognized as a promising tool across a vast variety of biomedical applications, with the potential to create novel therapeutic methods. However, the understanding of the molecular mechanisms behind non-thermal plasma cellular effects remains a significant challenge. In this study, we show how two types of different non-thermal plasmas induce cell death in mammalian cell cultures via the formation of multiple intracellular reactive oxygen/nitrogen species. Our results showed a discrepancy in the superoxide accumulation and lysosomal activity in response to air and helium plasma, suggesting that triggered signalling cascades might be grossly different between different plasmas. In addition, the effects of ozone, a considerable component of non-thermal plasma, have been simultaneously evaluated and have revealed much faster and higher cytotoxic effects. Our findings offer novel insight into plasma-induced cellular responses and provide a basis for better controlled biomedical applications.

Non-thermal plasmas hold great promise for a variety of biomedical applications. To ensure safe clinical application of plasma, a rigorous analysis of plasma-induced effects on cell functions is required. Yet mechanisms of bacteria deactivation by non-thermal plasma remain largely unknown. We therefore analyzed the influence of low-temperature atmospheric plasma on Gram-positive and Gram-negative bacteria. Using scanning electron microscopy, we demonstrate that both Gram-positive and Gram-negative bacteria strains in a minute were completely destroyed by helium plasma. In contrast, mesenchymal stem cells (MSCs) were not affected by the same treatment. Furthermore, histopathological analysis of hematoxylin and eosin–stained rat skin sections from plasma–treated animals did not reveal any abnormalities in comparison to control ones. We discuss possible physical mechanisms leading to the shred of bacteria under non-thermal plasma irradiation. Our findings disclose how helium plasma destroys bacteria and demonstrates the safe use of plasma treatment for MSCs and skin cells, highlighting the favorability of plasma applications for chronic wound therapy.

Nowadays, the focus in medicine on molecular genetics has resulted in a disregard for the physical basis of treatment even though many diseases originate from changes in cellular mechanics. Perturbations of the cellular nanomechanics promote pathologies, including cardiovascular disease and cancer. Furthermore, whilst the biological and therapeutic effects of magnetic fields are a well-established fact, to date the underlying mechanisms remain obscure. Here, we show that oscillating high-gradient magnetic field (HGMF) and mechanical vibration affect adipogenic differentiation of mesenchymal stem cells by the transmission of mechanical stress to the cell cytoskeleton, resulting in F-actin remodelling and subsequent down-regulation of adipogenic genes adiponectin, PPARγ, and AP2. Our findings propose an insight into the regulation of cellular nanomechanics, and provide a basis for better controlled down-regulation of stem cell adipogenesis by HGMF, which may facilitate the development of challenging therapeutic strategies suitable for the remote control of biological systems.