Cold Plasma Research Articles

Using plasma-activated water for decontamination of Salmonella spp. on common building surfaces in poultry houses

Plasma-activated water (PAW) has been shown to have antimicrobial properties, making it a promising tool for surface decontamination. This study evaluated the ability of PAW generated from high voltage atmospheric cold plasma to remove Salmonella from common surfaces (stainless steel (SS), polyvinyl chloride (PVC), concrete, and wood) found in poultry houses. PAW was generated by exposing distilled water to atmospheric cold plasma in 80% humid air at 90 kV and 60 Hz for 30 min. The resulting PAW contained 1120 ppm of nitrate and 1370 ppm of hydrogen peroxide, with a pH of 1.83. PAW was then applied to coupons of SS, PVC, wood, and concrete surfaces inoculated with 7–8 log10 CFU of cocktail of Salmonella spp. (S. Typhimurium, S. Newport, S. Montevideo, and S. Enteritidis). PAW effectively reduced Salmonella levels on SS and PVC surfaces to below the detection limit within 30 s. On wood surfaces, a longer treatment time of 7.5 min was required to achieve a maximum reduction of 2.63 log10 CFU, likely due to the porosity of the wood limiting PAW contact with the bacteria. On concrete surfaces, the reduction in Salmonella levels was only 0.98 log10 CFU. This was likely due to the greater surface roughness and high alkalinity, which neutralized the PAW species.

Impact of Cold Atmospheric Plasma Treatment on Native and Glycated Collagen

ABSTRACTCollagen is a major structural protein in the body, providing critical stability to the skin. Recent advancements have highlighted cold atmospheric plasma (CAP) as a versatile tool for various applications, including biomolecule modification, sterilization, food preservation, and wound healing. This study investigates the effects of CAP on both native and glycated collagen, analyzing the resulting changes. SEM and AFM analyses reveal that CAP induces protein self‐assembly in both glycated and non‐glycated collagen. Thioflavin assays further demonstrate that CAP‐treated glycated collagen exhibits greater fluorescence intensity compared to untreated glycated samples, indicating an increase in β‐sheet content and suggesting enhanced self‐assembly. These findings provide insights into the potential applications of CAP in modulating protein structures and understanding various biological processes and diseases.

Investigation of Microbiological Effects of Atmospheric Pressure Cold Plasma on Hand Disinfection

<b>Aim:</b> Atmospheric pressure cold plasma is the fourth state of matter obtained at low temperature with atmospheric pressure, which has antimicrobial, anti-inflammatory, sterilization, disinfection and surface modification enhancing properties. The aim of this study is to investigate the effectiveness of plasma activated medium (PAM) obtained from atmospheric pressure cold plasma on hand disinfection.<br /> <b>Methods and Materials</b>: The study was carried out on 15 individuals aged between 18 and 65 with healthy hand structures (no wounds, no pathology). Of the 15 individuals, 5 were selected as cleaning staff, 5 as office stuff, and 5 as academics. Samples were first taken from individuals using swap for bacterial identification. Afterwards, they were asked to wash their hands for 5 minutes in 250 ml PAM. At the end of the period, samples were taken from the individuals in the same way for bacterial identification using swap. The effectiveness of PAM in terms of hand disinfection was determined by comparing these two samples.<br /> <b>Results:</b> As a result of our study, it was found that bacterial colonies decreased in 3 of the samples taken from the hands of 5 cleaning personnel, remained stable in 2, a decrease in bacterial colonies in 4 of 5 office stuff, remained constant in 1, a decrease in bacterial colonies in 3 of 5 academicians, and remained stable in 2 of them. <i>Staphylococcus aureus, Staphylococcus epidermidis, Bacillus megaterium, Staphylococcus capitis, Streptococcus mitis, Staphylococcus warneri</i> bacteria were identified on the hands of individuals.<br /> <b>Conclusion:</b> As a result of our study, it was found that PAM, which has no side effects in the literature, can be an effective tool for hand disinfection.

Cold atmospheric plasma activation of human gingival fibroblasts for improved wound healing

Abstract Soft tissue regeneration plays a crucial role after oral surgery, as the successful healing of the soft tissue is a primary indicator of an efficacious intervention. Cold atmospheric plasma (CAP) has recently emerged as a promising therapeutic modality, exhibiting notable effects on cell migration and proliferation. Despite its potential, the dental application of CAP remains underexplored. This in vitro study aims to elucidate the impact of CAP activated medium on human gingival fibroblast responses, for future wound healing strategies. The study was divided into four parts: initial characterization of the plasma Jet, assessment of cell concentration, exploration of treatment distance effects, and treatment time dynamics. Human gingival fibroblasts were exposed to complete DMEM medium (without sodium pyruvate) activated with CAP at treatment distances of 2, 5, 7, and 9 mm, and treatment times of 15, 60, 120, 180, and 300 s for 1, 2 and 3 d of culture. The cell viability was evaluated using resazurin-based method, while wound healing dynamics was assessed via the scratch assay technique using phase-contrast microscopy. The cell morphology was characterised through fluorescence microscopy using propidium iodide and phalloidin staining, complemented by scanning electron microscopy. The results revealed that treatment distances and exposure times can influence the cell behaviour depending on the cell concentration. For the selected concentration of 1 × 104 cells ml−1, a treatment distance of 9 mm appeared to enhance human gingival fibroblast viability compared to a treatment distance of 2 mm and the control group. The images revealed adherent cells with a pattern typical of fibroblasts. However, no differences were observed for exposure times of 15 s and 180 s. The observed results further evidence that the exposure of the medium to the CAP device promoted an increase in cell viability, proliferation, and attachment in human gingival fibroblasts.

Therapeutic potential of plasma-treated solutions in atopic dermatitis

Atopic Dermatitis (AD) is a prevalent inflammatory skin disease that is currently incurable. Plasma-treated solutions (PTS) (e.g., culture media, water, or normal saline, previously exposed to plasma) are being studied as novel therapy. Recently, PTS is gaining attention due to its advantages over non-thermal plasma (also known as cold atmospheric plasma). Thus, we explore the application of PTS in treating AD. In vivo experiments demonstrated that PTS significantly alleviated AD-like symptoms. It reduced mast cell and macrophage infiltration, decreased scratching times and serum IgE levels. These therapeutic effects of PTS on AD mice were associated with the activation of the antioxidant molecule Nrf2. In vitro experiments revealed that PTS could decrease ROS level and regulate cytokine expression (such as IL-6, IL-10, IL-13 and CCL17) in TNF-α/IFN-γ-stimulated keratinocytes and LPS-stimulated M1 macrophages. Additionally, PTS could upregulate the expression of antioxidant stress molecules such as Nrf2, HO-1, NQO1 and PPAR-γ in both cell types. Overall, PTS demonstrated potent therapeutic potential for AD without notable side effects. Our research provided a promising approach to AD treatment and may serve as a potential therapeutic strategy in other inflammatory skin diseases.

Long-term-survival phase cells of Salmonella enteritidis ATCC 13076 exhibit significantly greater tolerance to atmospheric cold plasma treatment of shell eggs

The main objective of this study was to evaluate the tolerance of stationary phase (STAT) and long-term survival phase (LTS) Salmonella Enteritidis ATCC 13076 to atmospheric cold plasma (ACP) in phosphate buffered saline (PBS, pH 7.0) and on shell eggs. Salmonella Enteritidis was cultured in tryptic soy broth supplemented with 0.6% (w/v) yeast extract (35°C) for 20 h (STAT) and 21 days (LTS). Cell morphology was determined by light microscopy. The PBS and shell eggs were inoculated with STAT or LTS cells to obtain ∼7.0 log10 CFU/mL or egg. The ACP was applied at 45 kV (PBS) and 60 kV (shell eggs) for 1–4 min and 1–5 min, respectively. Pathogen survivors were enumerated on thin agar layer (TAL) medium and on xylose lysine tergitol-4 (XLT-4) agar after 48 h of incubation (35°C). For survivors on shell eggs, R2 and mean square error values were obtained using Log-linear with Tail and Weibull models. The STAT cells were predominantly rod-shaped whereas LTS cells were coccoid. In PBS, reductions (log10 CFU/mL) of STAT cells were 1.0, 0.95, 1.45, and 1.44 after exposure to ACP for 1, 2, 3, and 4 min, respectively. In contrast, reductions in LTS cells were significantly lower (p< 0.05) at 0.04 (1 min), 0.06 (2 min) 0.01 (3 min), and 0.11 (4 min). A similar pattern was observed for shell eggs whereby LTS cells exhibited much higher tolerance to ACP than STAT cells (p < 0.05). The Log-linear with Tail model produced a better fit of the survival data for STAT cells; times to achieve a 4- and 5- log reduction were 5.29 and 5.78 min, respectively. Sub-lethal injury occurred in both STAT and LTS survivors; however, differences were not significant (P > 0.05). Additionally, there were no observed differences in shell strength and yolk color between ACP-treated and control eggs. Based on these results, LTS cells of S. Enteritidis are more tolerant to ACP than STAT cells and should be considered when developing process validation protocols involving application of ACP to inactivate Salmonella on shell eggs.

Innovative Pathogen Reduction in Exported Sea Bass Through Atmospheric Cold Plasma Technology.

The safety of sea bass is critical for the global food trade. This study evaluated the effectiveness of atmospheric cold plasma in reducing food safety risks posed by Salmonella Enteritidis and Listeria monocytogenes, which can contaminate sea bass post harvest. Cold plasma was applied to inoculated sea bass for 2 to 18 min, achieving a maximum reduction of 1.43 log CFU/g for S. Enteritidis and 0.80 log CFU/g for L. monocytogenes at 18 min. Longer treatments resulted in greater reductions; however, odor and taste quality declined to a below average quality in samples treated for 12 min or longer. Plasma treatment did not significantly alter the color, texture, or water activity (aw) of the fish. Higher levels of thiobarbituric acid reactive substances (TBARSs) were observed with increased exposure times. Cold plasma was also tested in vitro on S. Enteritidis and L. monocytogenes on agar surfaces. A 4 min treatment eliminated the initial loads of S. Enteritidis (2.71 log CFU) and L. monocytogenes (2.98 log CFU). The findings highlight the potential of cold plasma in enhancing the safety of naturally contaminated fish. Cold plasma represents a promising technology for improving food safety in the global fish trade and continues to be a significant area of research in food science.

Physicochemical characterization and sensory enhancement of cold plasma treated black whole wheat flour

This study examined the effects of cold plasma (CP) treatment on the physicochemical properties and sensory quality of black whole wheat flour (BWWF). Various factors including nutrient composition, color, amino acids, aroma, particle size, microstructure, antioxidant activity, and water migration were analyzed before and after CP treatment. The findings revealed that CP treatment had a minimal impact on the baseline nutrient composition of BWWF, but significantly improved its free amino acid profile, enhancing its nutritional value. The treated BWWF had an improved surface color, appeared brighter and yellower, and gave off a pleasant mellow aroma, while removing unpleasant flavor. The total phenolic content of BWWF increased while the flavonoid and anthocyanin content decreased after the treatment. CP-treated BWWF underwent aggregation cross-linking in the microstructure, and the content of bound water decreased, but the stability increased. In conclusion, CP treatment had great potential to improve the physicochemical properties and sensory quality of BWWF.

Research Progress on Physical Preservation Technology of Fresh-Cut Fruits and Vegetables

Fresh-cut fruits and vegetables have become more popular among consumers because of their nutritional value and convenience. However, the lower shelf life of fresh-cut fruits and vegetables due to processing and mechanical damage is a critical factor affecting their market expansion, and advances in preservation technology are needed to prolong their shelf life. Some traditional chemical preservatives are disliked by health-seeking consumers because of worries about toxicity. Chemical preservation is inexpensive and highly efficient, but sometimes it carries risks for human health. Biological preservation methods are safer and more appealing, but they are not applicable to large-scale production. Physical fresh-keeping methods have been used for the storage and transportation of fresh-cut fruits and vegetables due to the ease of application. This review discusses current research in fresh-keeping technology for the preservation of fresh-cut fruits and vegetables. Preservation methods include low temperature, modified atmosphere packaging, cold plasma, pulsed light, ultrasonics, ultraviolet light, and ozonated water. As promising alternatives to chemical methods, these novel processes have been evaluated singly or combined with natural preservatives or other methods to extend the shelf life of fresh-cut fruits and vegetables and to provide references and assessments for further development and application of fresh-cut fruit and vegetable preservation technology.

Antigenicity elimination of ovalbumin by cold plasma-induced covalent binding with Gallic acid

The effect of cold plasma (CP) treatment in promoting the covalent grafting of ovalbumin (OVA) with gallic acid (GA) were investigated, along with identifying the binding sites in the OVA-GA complex and exploring its potential for reducing the antigenicity of OVA. The results showed that the GA content of 22.97 ± 1.27 mg/g in OVA-GA complex was obtained following 60 s of CP treatment. Using LC-MS/MS, four regions (T52-R59, V201-K207, I279-R285, and V281-K291) were identified, containing 12 GA binding sites in the OVA-GA complex. Additionally, a significant reduction in IgE binding capacity (70.83 ± 0.90 %) was observed, as confirmed by ELISA analysis. The masking/steric-hindrance effect on linear epitopes and the disruption of conformational epitopes of OVA as a result of GA grafting may be the key factors leading to the reduction in OVA antigenicity. This study highlights that promoting the grafting of polyphenols onto proteins using CP treatment is an effective strategy for reducing the antigenicity of protein allergens.

Soft tissue response to titanium healing abutments treated by Er: YAG laser or plasma spray: A randomized controlled feasibility clinical study with SEM and histological analysis.

Soft tissue seal around implants ensures stable osseointegration and a long-term survival of dental implants. Different surface modification and decontamination for implant abutments were endorsed in order to improve peri-implant soft tissue healing, such as laser, plasma spray, acid etching, and steaming. The aim of this study was to evaluate the response of peri-implant soft tissue to titanium abutments treated with Erbium-doped: Yttrium-Aluminum-Garnet (Er:YAG) laser versus plasma spray. Twenty-four patients who required implant placement in the maxillary arch participated in this study. Patients were divided into three groups, abutments treated with Er:YAG laser versus cold plasma spray and untreated abutments. Fourteen days following the implant abutment insertion, soft tissue peri-implant biopsies were taken for histological, histochemical, and immunohistochemical evaluation. Scanning electron microscopy was done for the abutments; plaque index (PI) and gingival index (GI) were assessed 14 days and 3 months following final restoration. Regarding the histological results, the least mean inflammatory cell count was in the plasma group (174.09 ± 40.67), followed by the laser group (654.27 ± 85.95) and the control group (852.00 ± 117.98), with statistically significant differences between them. The mean area fraction of collagen fibers showed the highest value in the plasma group (9.73 ± 1.91), followed by the laser group (3.25 ± 0.49), while the lowest value was found in the control group (1.17 ± 0.51). The immunohistochemical expression of E-cadherin was significantly higher and uniformly distributed in the plasma group (42.4 ± 11.2%) followed by the laser group (15.4 ± 4.07%) and the control group (6.8 ± 1.7%). SEM analysis of healing abutments showed fibroblast-like cells, which were more developed with dense fibers in the plasma group; laser group fibers showed fewer and more delicate fibers than the plasma group, while no fibers were detected in the control group. Within the limitations of this feasibility study, the present data concluded that plasma spray and Erbium: YAG laser can be used for abutment surface treatment to achieve better peri-implant soft tissue healing. Clinically and histologically, plasma spray showed a better effect on the peri-implant soft tissues by reducing the inflammatory reaction, promoting collagen fiber formation, higher fibroblast-like cell attachment, and upregulating E-cadherin expression than Erbium: YAG laser and control groups.

Reduction of Adverse Effects of Drought Stress on Germination Indices and Antioxidant Enzymes of Licorice Seeds (Glycyrrhiza) Using Cold Plasma

Reduction of Adverse Effects of Drought Stress on Germination Indices and Antioxidant Enzymes of Licorice Seeds (Glycyrrhiza) Using Cold Plasma

Impact of hot plasma effects on electron cyclotron current drive in tokamak plasmas

Abstract Focusing on the impact of hot plasma effects on electron cyclotron current drive (ECCD), this paper presents the numerical results of top launch ECCD (TL-ECCD) and outside midplane or equatorial-plane launch ECCD (EL-ECCD) in the HL-3-like tokamak plasmas. For EL-ECCD, there is little difference in the calculated results under the cold and hot plasma propagation models, and the results are not affected by the dominant current drive mechanism of EC waves. In the cases of TL-ECCD, the large initial parallel refraction makes the influence of hot plasma effects on ECCD become significant. In the range of toroidal magnetic fields BT discussed in this paper, the difference between the calculated results under the two propagation models rapidly decreases as the value of BT decreases, and the difference between the two is already very small in the range of 1.8 T ≤ BT ≤ 2.0 T. Therefore, the influence of hot plasma effects can also be neglected for TL-ECCD, and the cold plasma propagation model can be directly adopted. For the HL-3-like tokamak equipped with a dual-frequency EC wave system at 140 GHz and 105 GHz, if the addition of a TL-ECCD is considered in the existing outside midplane and upper launch manners, through appropriate combination of 140 GHz TL-ECCD and dual-frequency outside EL-ECCD, the ECCD can be used in a larger BT window (1.8 T ≤ BT ≤ 2.25 T) and a wider radial range (0.1 ≤ ρ ≤ 0.8 ~ 0.9) to generate current efficiently. The normalized current drive efficiency of the TL-ECCD is nonlinear with the injected EC power, it reaches the maximum at the injected power of 6 ~ 8 MW. This is of significance for the stable operation of HL-3-like tokamak with high plasma current above 1 MA.

Atmospheric cold plasma pretreatment for effective enhancement of covalent crosslinking between coconut globulin and tannic acid: Improving interfacial activity and emulsifying properties

Atmospheric cold plasma (ACP) represents a promising approach for enhancing covalent interactions between proteins and polyphenols, circumventing the drawbacks associated with traditional methods. This study aims to investigate the enhancement of covalent interactions between coconut globulin (CG) and tannic acid (TA) facilitated by ACP at varying pH levels. At acidic pH, ACP treatment was found to promote free radical-induced covalent cross-linking between CG and TA, whereas at pH 7.0 and 9.0, ACP treatment enhanced quinone-induced covalent cross-linking. In contrast, the covalent crosslinking induced by quinone significantly disrupted the protein structure, leading to greater exposure of hydrophobic groups. At pH 9.0, the CG-TA complex treated with ACP exhibited the highest interfacial activity, with an interfacial adsorption mass of 5292 ng/cm2. This was accompanied by improvements in droplet size, viscosity, and stability of the CG-TA-stabilized emulsion. These findings offer novel insights into the covalent modification of proteins and polyphenols, thereby broadening the potential applications of food protein.

Sublethal Damage Caused by Cold Plasma on Bacillus cereus Cells: Impact on Cell Viability and Biofilm-Forming Capacity.

The Bacillus cereus group represents a serious risk in powdered and amylaceous foodstuffs. Cold plasma (the fourth state of matter) is emerging as an alternative effective nonthermal technology for pasteurizing a wide range of matrices in solid, liquid, and powder form. The present study aims to evaluate the mechanisms involved in Bacillus cereus inactivation via cold plasma, focusing on (i) the technology's ability to generate damage in cells (at the morphological and molecular levels) and (ii) studying the effectiveness of cold plasma in biofilm mitigation through the direct effect and inhibition of the biofilm-forming capacity of sublethally damaged cells post-treatment. Dielectric barrier discharge cold plasma (DBD-CP) technology was used to inactivate B. cereus, B. thuringiensis, and B. mycoides under plasma power settings of 100, 200, and 300 W and treatment times ranging from 1 to 10 min. Inactivation levels were achieved in 2-7 log10 cycles under the studied conditions. Percentages of sublethally damaged cells were observed in a range of 45-98%, specifically at treatment times below 7 min. The sublethally damaged cells showed poration, erosion, and loss of integrity at the superficial level. At the molecular level, proteins and DNA leakage were also observed for B. cereus but were minimal for B. mycoides. Biofilms formed by B. cereus were progressively disintegrated under the DBD-CP treatment. The greater the CP treatment intensity, the greater the tearing of the bacteria's biofilm network. Additionally, cells sublethally damaged by DBD-CP were evaluated in terms of their biofilm-forming capacity. Significant losses in the damaged cells' biofilm network density and aggregation capacity were observed when B. cereus was recovered after inactivation at 300 W for 7.5 min, compared with the untreated cells. These results provide new insights into the future of tailored DBD-CP design conditions for both the inactivation and biofilm reduction capacity of B. cereus sensu lato species, demonstrating the effectiveness of cold plasma and the risks associated with sublethal damage generation.

Combined high voltage atmospheric cold plasma and ultraviolet-cold plasma inhibited Aspergillus flavus growth and improved physicochemical properties of protein in peanuts

To improve the application value of peanuts, the fungicidal effect and physicochemical properties of the protein in peanuts were investigated by combining high voltage atmospheric cold plasma (HVCP) and ultraviolet-cold plasma (UVCP) in this study. Compared to the single HVCP or UVCP treatment, the combined treatments exhibited a higher fungicidal efficiency of A. flavus spores in peanuts, decreasing by 0.79–2.97 log10 cfu/g after 8-min treatment. The A. flavus growth and aflatoxin production in peanuts during storage were also lower than the single plasma groups. Moreover, cold plasma treatments could modify the molecular structures of protein in peanuts by changing secondary and tertiary structures, decreasing particle size and increasing zeta potential, which contributed to improve the solubility and emulsification of protein. Overall, this research provides a unique strategy for the combined application of cold plasma in grain decontamination and protein modification.

Effect of cold plasma on plant physiological and biochemical processes: A review

Effect of cold plasma on plant physiological and biochemical processes: A review

Cold plasma irradiation inhibits skin cancer via ferroptosis

Cold atmospheric plasma (CAP) has been extensively utilized in medical treatment, particularly in cancer therapy. However, the underlying mechanism of CAP in skin cancer treatment remains elusive. In this study, we established a skin cancer model using CAP treatmentin vitro. Also, we established the Xenograft experiment modelin vivo. The results demonstrated that treatment with CAP induced ferroptosis, resulting in a significant reduction in the viability, migration, and invasive capacities of A431 squamous cell carcinoma, a type of skin cancer. Mechanistically, the significant production of reactive oxygen species (ROS) by CAP induces DNA damage, which then activates Ataxia-telangiectasia mutated (ATM) and p53 through acetylation, while simultaneously suppressing the expression of Solute Carrier Family 7 Member 11 (SLC7A11). Consequently, this cascade led to the down-regulation of intracellular Glutathione peroxidase 4 (GPX4), ultimately resulting in ferroptosis. CAP exhibits a favorable impact on skin cancer treatment, suggesting its potential medical application in skin cancer therapy.

Cold Plasma Technology: A Sustainable Approach to Milk Preservation by Reducing Pathogens and Enhancing Oxidative Stability

Cold Plasma Technology: A Sustainable Approach to Milk Preservation by Reducing Pathogens and Enhancing Oxidative Stability

The effect of variations in cold plasma conditions on the detoxification of Aflatoxin M1 and degradation products

The aim of this study was to explore the chemical reactive species of different operating gases, and their effect on the degradation of aflatoxin M1 (AFM1) by cold plasma by measuring the reactive species concentration. Helium, at 80, 90 or 95%, was used mixed with oxygen, nitrogen and air. The efficacy of cold plasma on aflatoxin M1 (AFM1) reduction was improved when decreasing the ratio of helium in the gas mixture. The ratio of the gas mixtures changed the cold plasma chemistry believed to be due to the differences in the concentrations of the reactive species. The degradation products of AFM1 after cold plasma treatment using a helium/air gas mixture and the degradation pathway were identified by LCMS. AFM1 was oxidised by reactive species in the cold plasma to produce degradant products with, theoretically, lower toxicity than AFM1.