Search Results (74)

Objective: This study evaluated the effectiveness of a new cold atmospheric plasma device (AmbiJet) for eradicating mature oral biofilm on titanium implant surfaces, aiming to improve decontamination methods for the treatment of peri-implant infections. Material and methods: Mature oral biofilms were grown on titanium disks placed in participants’ mouths. These disks were divided into control and plasma treatment groups. The AmbiJet device delivered plasma directly to the implant surface for 3 min per 20 mm², utilizing the applicator nozzle and implant as electrodes. Biofilm reduction was quantified by counting colony-forming units (CFUs). Results: Cold plasma treatment rendered approximately 90% of samples bacteria-free. A > 6-log₁₀ reduction (≈99.9999%) in bacterial load was achieved in 30% of samples, with an overall average reduction of 4.9-log₁₀ across all treated samples. The temperature during treatment remained below 40 °C. Conclusions: Within the study’s limitations, cold atmospheric plasma effectively eradicates mature oral biofilm on titanium surfaces. This high disinfection efficacy is likely due to the combined action of reactive species and electrical phenomena, which does not cause significant temperature increases. Full article

The extension of shelf-life and enhancement of the safety and quality of fresh-cut ready-to-eat vegetables is an ongoing public health concern. The present study investigated the efficacy of cold atmospheric plasma (CAP) treatment for the decontamination of fresh-cut carrots inoculated with Escherichia coli. An atmospheric plasma jet system operating at 1 kVA was utilized for treatment with varying plasma jet nozzle to sample distances (10–40 mm), exposure times (10–60 s) and either argon or dry air at 3 bar as working gases. It was demonstrated that both working gases achieved more than 4 log reductions in E. coli within 60 s of treatment while maintaining carrot surface temperatures below 50 °C. During 3-week storage at 4 °C, the immediate effects of plasma treatment on quality parameters were found to be minimal, with no significant changes observed in color (ΔE < 3.0) parameters, β-carotene content, ascorbic acid levels, total phenolic content (TPC), or total antioxidant activity (TAA) following either treatment. Additionally, plasma-treated carrots retained their firmness, showing no significant texture loss, whereas untreated controls experienced a firmness decline of approximately 9% by the end of storage. Notably, TPC increased by up to 41%, and TAA increased significantly (p < 0.05) in plasma-treated samples during storage, especially in dry air plasma-treated carrots. These results demonstrated that CAP treatment can be successfully applied for rapid inactivation of E. coli on fresh-cut carrot surfaces while preserving original quality characteristics during refrigerated storage, offering potential as non-thermal preservation technology for fresh produce. Full article

Cold atmospheric plasma (CAP) is emerging as an innovative approach for cancer treatment because of its selectivity for malignant cells and absence of significant adverse effects. While modern oncological therapies face challenges such as tumor heterogeneity and treatment resistance, CAP presents itself as a low-cost and environmentally sustainable alternative. Its mechanisms of action involve reactive oxygen and nitrogen species (RONS), UV radiation, and electromagnetic fields, which induce cell death. Preclinical and clinical studies have demonstrated the efficacy of CAP, with devices such as dielectric barrier discharge (DBD) and the plasma jet developed to minimize damage to healthy cells. Some CAP devices are already approved for clinical use, showing safety and efficacy. However, the standardization of treatments remains a challenge due to the variety of devices and parameters used. Although CAP has shown promising cytotoxic effects in vitro and in animal models, especially in different cancer cell lines, further research, particularly in vivo and in veterinary medicine, is needed to optimize its clinical use and maximize its efficacy in combating cancer. Full article

Network analysis is a convenient method for analyzing cold atmospheric plasma (CAP) devices across a wide range of operating conditions. By using frequency and voltage as nodes in the network, edges are formed between nodes when the combination of voltage and frequency results in an ignited plasma jet. Singular value decomposition is used to identify modalities in the network that are representative of operational modes in the plasma jet. An analysis of the spectra produced by the jet provides validation of the operational modes and shows that voltage and frequency predominately affect the operation of the jet with remarkable independence. Full article

Cold atmospheric plasma (CAP) treatment induces cancer cell death through the generation of reactive oxygen and nitrogen species (RONS). However, the efficacy of RONS delivery into cells remains limited by membrane permeability. Here, we investigated whether combining CAP with pulsed electric fields (PEFs) could enhance cancer cell death through increased intracellular RONS uptake. HeLa cells were treated with argon atmospheric pressure plasma jet (Ar-APPJ), PEF, or their combination. The combined treatment showed significantly enhanced cell death compared to single treatments. While PEF treatment alone induced membrane permeabilization, the combination with Ar-APPJ resulted in more pronounced and sustained membrane disruption, as evidenced by increased calcein leakage. This enhanced effect was attributed to Ar-APPJ-induced lipid peroxidation interfering with membrane resealing after PEF-induced electroporation. We also demonstrated that PEF-induced membrane electroporation facilitates the intracellular uptake of CAP-generated RONS. These findings provide mechanistic insights into the synergistic effects of combined CAP and PEF treatments, suggesting enhanced cell death via multiple pathways. Full article

In view of a constant growth in the human population on Earth, the provision of a necessary amount of high-quality food looks challenging. As over 10% of the crop yields are annually lost due to the presence of phytopathogens, the development of novel, eco-friendly methods of pest eradication might contribute to avoiding nutritional shortages. Here, we propose a controlled application of cold atmospheric pressure plasma (CAPP) generated in the form of an atmospheric pressure plasma jet (APPJ), for which we conducted multivariate optimization of the working parameters with the use of the design of experiments (DoE) in addition to the response surface methodology (RSM). After estimating the optimal operating conditions of APPJ, we determined the inactivation rates caused by 2 min CAPP exposure towards bacterial phytopathogens from three species Dickeya solani, Pectobacterium atrosepticum and Pectobacterium carotovorum artificially inoculated on the surface of plant seeds from four species. Logarithmic reductions, as a key result of this work, were enclosed in the range of 1.61–4.95 in the case of Cucumis sativus, Pisum sativum, and Vigna radiata, while for the bacteria-inoculated Zea mays seeds, lower antibacterial properties of APPJ equaling 0.86–1.12 logs were noted. The herein applied exposure to APPJ did not reveal any statistically significant detrimental effects on the germination of plant seeds, seed coat integrity, or early plant growth. Even plant growth promotion by 20.96% was observed for the APPJ-exposed Zea mays seeds. By applying colorimetric assays and optical emission spectrometry (OES), we determined the oxidative potential in addition to identifying the reactive oxygen species (ROS) ^•OH, ^•HO₂, ^•O₂⁻, O₃, and ¹O₂ and the reactive nitrogen species (RNS) N, NO₂, and NO₃ responsible for the antibacterial properties of APPJ. In summary, universal antiphytopathogenic properties of the APPJ treatment reached due to proper optimization of the working conditions were revealed against three bacterial strains from the family Pectobacteriaceae inoculated on the seeds from diverse plant species. The data presented herein may contribute to future development of the plasma agriculture field and provide alternatives to pesticides or the prevention-based control methods towards plant pathogenic bacteria. Full article

Due to its antimicrobial, anti-inflammatory and pro-healing properties, the application of cold atmospheric plasma (CAP) has emerged as a new and promising therapeutic strategy in various fields of medicine, including general medicine and dentistry. In this light, the aim of the present study was to investigate the effects of a homemade plasma jet on the cellular behaviour of two important cell types involved in gingivitis, namely gingival fibroblasts (HGF-1 cell line) and macrophages (RAW 264.7 cell line), by the direct application of CAP in different experimental conditions. The cellular behaviour of the HGF-1 cells was investigated in terms of viability/proliferation (LIVE/DEAD and CCK-8 assays), morphological features (immunofluorescent staining of the actin cytoskeleton) and fibronectin expression (immunocytochemical staining of the fibronectin network), while the macrophages’ response was evaluated through the assessment of the cellular survival/proliferation rate (LIVE/DEAD and CCK-8 assays), morphological behaviour (immunofluorescent staining of the actin cytoskeleton) and inflammatory activity (pro-inflammatory cytokine secretion profile (ELISA assay) and foreign body giant cells (FBGCs) formation (immunofluorescent staining of the actin cytoskeleton and multinuclearity index determination)). The in vitro biological assessment revealed an upward trend dependent on treatment time and number of CAP applications, in terms of fibroblasts proliferation (p < 0.0001) and fibronectin expression (p < 0.0001). On the other hand, the macrophages exposed to five consecutive CAP applications for longer treatment times (over 120 s) exhibited a strong pro-inflammatory activity, as evinced by their altered morphology, pro-inflammatory cytokine profile (p < 0.0001) and FBGCs formation. Overall, our results demonstrate that CAP exposure, when used with appropriate operating parameters, has a beneficial effect on the cellular response of HGF-1 and RAW 264.7 cells, thus paving the way for further in vitro and in vivo investigations that will allow the translation of CAP treatment from research to clinic as an alternative therapy for gingivitis. Full article

A cold atmospheric-pressure He-plasma jet (CAPPJ) interacts with air and water, producing reactive oxygen and nitrogen species (RONS), including biologically active ions, radicals, and molecules such as NO_x, H₂O₂, HNO₃, HNO₂, and O₃. These compounds can activate interfacial redox processes in biological tissues. The CAPPJ can oxidize N₂ to HNO₃ and water to H₂O₂ at the interface between plasma and water. It can also induce the oxidation of water-soluble redox compounds in various organisms and in vitro. This includes salicylic acid, hydroquinone, and mixtures of antioxidants such as L (+)-ascorbic acid sodium salt with NADPH. It can react with redox indicators, such as ferroin, in a three-phase system consisting of air, CAPPJ, and water. Without reducing agents in the water, the CAPPJ will oxidize the water and decrease the pH of the solution. When antioxidants such as ascorbate, 1,4-hydroquinone, or NADPH are present in the aqueous phase, the CAPPJ oxidizes these substances first and then oxidizes water to H₂O₂. The multielectron mechanisms of the redox reactions in the plasma-air/water interfacial area are discussed and analyzed. Full article

Mesoscale convective systems are effective sources of atmospheric disturbances that can reach ionospheric heights and significantly alter atmospheric and ionospheric conditions. Convective systems can affect the Earth’s atmosphere on a continental scale and up to F-layer heights. Extratropical cyclone “Zyprian” occurred at the beginning of July, 2021 and dominated weather over the whole of Europe. An extensive cold front associated with “Zyprian” moved from the western part to the eastern part of Europe, followed by ground-level convergence and the formation of organized convective thunderstorm systems. Torrential rains in the Czech Republic have caused a great deal of damage and casualties. Storm-related signatures were developed in ground microbarograph measurements of infrasound and gravity waves. Within the stratosphere, a shift of the polar jet stream and increase in specific humidity related to the storm system were observed. At the ionospheric heights, irregular stratification and radio wave reflection plane undulation were observed. An increase in wave-like activity was detected based on ionograms and narrowband very-low-frequency (VLF) data. On directograms and SKYmaps (both products of digisonde measurements), strong and rapid changes in the horizontal plasma motion were recorded. However, no prevailing plasma motion direction was identified within the F-layer. Increased variability within the ionosphere is attributed mainly to the “Zyprian” cyclone as it developed during low geomagnetic activity and stable solar forcing. Full article

Tracheal stenosis (i.e., the abnormal narrowing of the trachea) can occur due to a variety of inflammatory and infectious processes as well as due to therapeutic procedures undertaken by the patient. The most common cause of tracheal obstruction in patients has been prolonged intubation. Depending on the extent of the stenosis and its exact location, the surgical insertion of a tracheal stent is the only option for addressing this issue. The Montgomery T-tube implant is a valuable tracheal stent made from medical-grade silicone that provides a functional airway while supporting the tracheal mucosa. However, its performance is subject to gradual deterioration due to biofilm colonization of the stent’s inner wall, which may explain the discomfort claimed by many patients and clinical failures. Recently, cold atmospheric plasmas (CAPs) have emerged as an alternative technology to many conventional medical procedures, such as wound healing, skin treatment, decontamination of medical devices, etc. Here, we report on plasma-induced surface modification of the inner wall of a T-tube implant, considering future biomedical applications. To generate the plasma, we employed a cold atmospheric pressure plasma jet in gas helium, which was directly inserted into the T-tube implant. To assess the treatment uniformity, the degree of surface modification and its extension along the stent’s inner wall was analyzed using different process parameters. Full article

Oral mucositis associated with candidiasis can causes systemic candidemia, posing a risk to cancer patients administered antineoplastic therapy. Cold atmospheric pressure plasma jets (CAPPJs) have antifungal and anti-inflammatory properties. This study evaluated the effects CAPPJs in preventing systemic fungal dissemination in a murine model of oral mucositis associated with candidiasis. Forty Wistar rats were divided into groups: CAPPJs (treated) and non-treated controls (for comparison), with subgroups subject to 24 and 72 h of treatment (n = 10 each). Four cycles of chemotherapy (cisplatin and 5-fluorouracil (5-FU)) were administered, followed by oral inoculation of Candida albicans for 3 days. Mucosal damage was induced on the lateral side of tongue with 50% acetic acid. CAPPJ treatment was performed on the lesion for 5 min (2 days). Body weight was assessed daily. Fungal dissemination was conducted using organ macerates and plated on Sabouraud Agar with chloramphenicol. Blood samples were obtained for blood count tests. Chemotherapy affected the general health of the animals, as evidenced by body weight loss. Treatment with CAPPJs showed an inhibitory effect on C. albicans, with a significant reduction in fungal recovery from the tongue after 24 h (p < 0.05). Interestingly, systemic fungal dissemination was significantly reduced after 24 and 72 h of treatment when compared to control (p < 0.05). Taken together, these results suggest that CAPPJs have potential for clinical application in patients with oral mucositis at risk of candidemia. Full article

The impact of cold atmospheric plasma (CAP) treatment on the enamel of twelve primary teeth (incisors, canines, and molars) collected from six children was examined in order to evaluate the possibility of using the CAP technique in dental applications. A radio-frequency dielectric barrier discharge (DBD) plasma jet operating at a voltage of 3.25 kV using a mixture of helium and oxygen as the working gas was used for the generation of plasma as part of the electro-technological method for the treatment of biological material. The plasma exposure time for the primary teeth was 5, 10, and 20 min. The properties of tooth enamel (color, contact angles, surface roughness, surface topography, elemental composition) were examined before (control) and after the plasma treatment. As shown by the results, the plasma treatment time is a key parameter that can induce desired features, such as whitening or improved wettability. However, with prolonged plasma treatment (20 min), the enamel surface may be permanently damaged. The cold-plasma-treated samples were characterized by a higher value of the brightness L* parameter and thus a lighter color, compared to the CAP-untreated teeth. It was also evidenced that the plasma treatment increased the hydrophilicity of tooth surfaces, and the contact angles effectively decreased with the time of the CAP treatment. The tooth surface also became much more heterogeneous and rough with much greater amplitudes in heights. The surface of the primary teeth after the CAP treatment lost its homogeneity, as evidenced by the SEM micrographs. The analysis of the elemental composition revealed only minor changes after the plasma process, which may suggest that the observed morphological changes in the enamel surface are mainly physical and are not a consequence of chemical reactions between the enamel and the reactive components of the cold plasma. Plasma treatment of teeth opens up new possibilities of using this method as an alternative to whitening or pre-treatment before other dental procedures. Full article

Cold atmospheric plasma (CAP) is a promising alternative to antibiotics and chemical substances in dentistry that can reduce the risk of unwanted side effects and bacterial resistance. AmbiJet is a device that can ignite and deliver plasma directly to the site of action for maximum effectiveness. The aim of the study was to investigate its antimicrobial efficacy and the possible development of bacterial resistance. The antimicrobial effect of the plasma was tested under aerobic and anaerobic conditions on bacteria (five aerobic, three anaerobic (Gram +/−)) that are relevant in dentistry. The application times varied from 1 to 7 min. Possible bacterial resistance was evaluated by repeated plasma applications (10 times in 50 days). A possible increase in temperature was measured. Plasma effectively killed 10⁶ seeded aerobic and anaerobic bacteria after an application time of 1 min per 10 mm². Neither the development of resistance nor an increase in temperature above 40 °C was observed, so patient discomfort can be ruled out. The plasma treatment proved to be effective under anaerobic conditions, so the influence of ROS can be questioned. Our results show that AmbiJet efficiently eliminates pathogenic oral bacteria. Therefore, it can be advocated for clinical therapeutic use. Full article

Bio-based solutions for solid timber gluing have always been a very sensitive topic in wood technology. In this work, we optimize the gluing conditions of a starch–tannin formulation, which allows high performance in dry conditions and resistance to water dipping for 3 h, allowing for the D2 classification to be reached according to EN 204. It was observed that the starch–tannin formulations enhanced their performance by increasing the heating temperature, achieving satisfactory results at 140 °C for 13 min. The proportion of polyphenols in the mixture enhances the water resistance but is only tolerated until 20–30%. In particular, the addition of 10% tannin–hexamine enhances the water-resistant properties of starch for both quebracho and chestnut extract. The application of the jet of cold atmospheric plasma allows for good results with more viscous formulations, increasing their penetration in wood. Solid-state ¹³C-NMR analysis was also performed, and the spectroscopic information suggests establishing a coordination complex between starch and tannin. Full article

Atmospheric pressure cold plasmas have recently been the subject of intense research and applications for solving problems in the fields of energy, environmental engineering, and biomedicine. Non-thermal atmospheric pressure plasma sources, with dielectric barrier discharges, plasma jets, and arc discharges, are non-linear power loads. They require special power systems, which are usually designed separately for each type of plasma reactor, depending on the requirements of the plasma-chemical process, the power of the receiver, the type of process gas, the current, voltage and frequency requirements, and the efficiency of the power source. This paper presents non-linear phenomena accompanying plasma generation in the power supply plasma reactor system, such as harmonic generation, resonance, and ferroresonance of currents and voltages, and the switching of overvoltages and pulse generation. When properly applied, this can support the operation of the above-mentioned reactors by providing improved discharge ignition depending on the working gas, thus increasing the efficiency of the plasma process and improving the cooperation of the plasma-generation system with the power supply. Full article