Low-temperature atmospheric-pressure plasma sources for plasma medicine

Effects of combined modification of sulfonation, oxygen plasma and silane on the bond strength of PEEK to resin

OBJECTIVE

This study aimed to evaluate the combined effects of sulfonation, non-thermal oxygen plasma and silane on the shear bond strength (SBS) of PEEK to resin materials.

MATERIALS AND METHODS

Two hundred and eighty specimens were randomly divided into four groups: (A) untreated; (B) sulfonation for 60 s; (C) oxygen plasma for 20 min; (D) sulfonation for 60 s and oxygen plasma for 20 min. According to the instructions, 120 samples (N = 30) were coated with silane, adhesive, and resin composites. Each group of bonding specimens was divided into two subgroups (n = 15) to measure immediate and post-aging SBS. The surface morphology and the interface between the samples and adhesive were analyzed through SEM. Physicochemical characteristics of the surface and mechanical properties were determined through XPS, FTIR, light interferometry, contact angle measurement, and three-point bending tests.

RESULTS

Sulfonation produced a porous layer of approximately 20 µm thickness on the surface, and the oxygen plasma increased the O/C ratio and oxygen-containing groups of the sample surface. After coating with silane, the SBS values of sulfonated PEEK and plasma-treated PEEK increased (9.96 and 10.72 MPa, respectively), and dual-modified PEEK exhibited the highest SBS value (20.99 MPa), which was significantly higher than that of blank group (p > 0.01). After 10,000 thermal cycles, the dual-modified PEEK still displayed a favorable SBS (18.68 MPa).

SIGNIFICANCE

Sulfonation strengthened the mechanical interlocking between PEEK and the resin while oxygen plasma established a chemical bonding between silane and PEEK. This dual modification of the surface microstructure and chemical state synergistically improved the bond strength of PEEK to resin and resulted in considerable long-term effects.

Enhancing Titanium Disk Performance through In-Pack Cold Atmospheric Plasma Treatment

While titanium dental implants have already been clinically established, ongoing research is continuously being conducted to advance the fields of osseointegration and bacterial resistance, seeking further improvements in these areas. In this study, we introduce an innovative method for treating titanium surfaces within tightly sealed packaging. Specifically, titanium discs, enclosed in surgical-grade packaging, underwent treatment using cold atmospheric plasma (CAP). The surfaces were thoroughly characterized in terms of wettability, crystalline structure, and chemical composition. Hemocompatibility analyses were conducted using blood diluted in sodium citrate (1:9) exposed to titanium discs for 30 min inside a CO2 incubator at 37 °C. Subsequently, various blood parameters were evaluated, including prothrombin time (PT), activated partial thromboplastin time (APTT), and platelet adhesion. Microbiological analyses were also performed using Pseudomonas aeruginosa (ATCC 27853) for 4 h at 37 °C. The treatment with CAP Jet resulted in a reduction in contact angle without causing any changes in the crystalline structure. No statistically significant differences were observed in the blood parameters. The plasma-treated samples exhibited lower PT and APTT values compared to those of the control group. The surfaces treated with CAP Jet showed increased platelet activation, platelet density, and thrombus formation when compared with the untreated samples. Moreover, the treated surfaces demonstrated lower bacterial colony formation compared with other surfaces.

Plasma-Droplet Fusion-Mass Spectrometry Reveals Sub-Millisecond Protein Unfolding Dynamics Induced by Reactive Oxygen Species

Investigating the connection between reactive oxygen species (ROS) and oxidative protein unfolding is critical to reveal the mechanisms underlying disease involving elevated ROS and protein misfolding. This could inform the development of therapeutics targeting cells based on their redox status. In this study, we developed a plasma-droplet fusion-mass spectrometry platform to rapidly assess protein resilience to ROS. This home-built system fuses ROS generated from the microplasma source with protein microdroplets from a tunable nanospray source. At the droplet-plasma intersection, ROS interact with proteins before entering the mass spectrometer for mass identification and structural characterization. Benefiting from the small-sized microdroplet with adjustable traveling velocity, the platform enables the first sub-millisecond kinetic study of ROS-induced protein unfolding, with a rate constant of approximately 1.81 ms-1. Capturing ROS-induced protein unfolding intermediates and the resultant ligand release dynamics can be extended to many more protein systems. We foresee broad applications for establishing previously undetected protein unfolding events when biologically impactful ROS are enriched in time and space with functional proteins and complexes.

A Review of Recombination Coefficients of Neutral Oxygen Atoms for Various Materials

Relevant data on heterogeneous surface recombination of neutral oxygen atoms available in the scientific literature are reviewed and discussed for various materials. The coefficients are determined by placing the samples either in non-equilibrium oxygen plasma or its afterglow. The experimental methods used to determine the coefficients are examined and categorized into calorimetry, actinometry, NO titration, laser-induced fluorescence, and various other methods and their combinations. Some numerical models for recombination coefficient determination are also examined. Correlations are drawn between the experimental parameters and the reported coefficients. Different materials are examined and categorized according to reported recombination coefficients into catalytic, semi-catalytic, and inert materials. Measurements from the literature of the recombination coefficients for some materials are compiled and compared, along with the possible system pressure and material surface temperature dependence of the materials' recombination coefficient. A large scattering of results reported by different authors is discussed, and possible explanations are provided.

Development of an Environmentally Friendly Technology for the Treatment of Aqueous Solutions with High-Purity Plasma for the Cultivation of Cotton, Wheat and Strawberries

The microwave setup for obtaining plasma-activated water (PAW) has been created. PAW contains significant concentrations of H2O2 and NO3−, has a reduced content of O2, high conductivity, a high redox potential and low pH. Likewise, the specific electrical conductivity and concentration of H2O2 and NO3− linearly depend on the treatment time. These parameters are simple and convenient markers for controlling the preparation of PAW. It has been established that PAW solutions with a concentration of 0.5–1.0% increase the germination energy, protect against fusarium and hyperthermia in cotton, wheat and strawberry seeds. In addition, PAWs have a positive effect on the growth rate of plants in the early stages of development. The use of PAW provides significant benefits over the chemical preparations Dalbron and Bakhor, so-called seed germination stimulators (SDS).

Plasma-Assisted Nanofabrication: The Potential and Challenges in Atomic Layer Deposition and Etching

The growing need for increasingly miniaturized devices has placed high importance and demands on nanofabrication technologies with high-quality, low temperatures, and low-cost techniques. In the past few years, the development and recent advances in atomic layer deposition (ALD) processes boosted interest in their use in advanced electronic and nano/microelectromechanical systems (NEMS/MEMS) device manufacturing. In this context, non-thermal plasma (NTP) technology has been highlighted because it allowed the ALD technique to expand its process window and the fabrication of several nanomaterials at reduced temperatures, allowing thermosensitive substrates to be covered with good formability and uniformity. In this review article, we comprehensively describe how the NTP changed the ALD universe and expanded it in device fabrication for different applications. We also present an overview of the efforts and developed strategies to gather the NTP and ALD technologies with the consecutive formation of plasma-assisted ALD (PA-ALD) technique, which has been successfully applied in nanofabrication and surface modification. The advantages and limitations currently faced by this technique are presented and discussed. We conclude this review by showing the atomic layer etching (ALE) technique, another development of NTP and ALD junction that has gained more and more attention by allowing significant advancements in plasma-assisted nanofabrication.

Biological Risk Assessment of Three Dental Composite Materials following Gas Plasma Exposure

Gas plasma is an approved technology that generates a plethora of reactive oxygen species, which are actively applied for chronic wound healing. Its particular antimicrobial action has spurred interest in other medical fields, such as periodontitis in dentistry. Recent work has indicated the possibility of performing gas plasma-mediated biofilm removal on teeth. Teeth frequently contain restoration materials for filling cavities, e.g., resin-based composites. However, it is unknown if such materials are altered upon gas plasma exposure. To this end, we generated a new in-house workflow for three commonly used resin-based composites following gas plasma treatment and incubated the material with human HaCaT keratinocytes in vitro. Cytotoxicity was investigated by metabolic activity analysis, flow cytometry, and quantitative high-content fluorescence imaging. The inflammatory consequences were assessed using quantitative analysis of 13 different chemokines and cytokines in the culture supernatants. Hydrogen peroxide served as the control condition. A modest but significant cytotoxic effect was observed in the metabolic activity and viability after plasma treatment for all three composites. This was only partially treatment time-dependent and the composites alone affected the cells to some extent, as evident by differential secretion profiles of VEGF, for example. Gas plasma composite modification markedly elevated the secretion of IL6, IL8, IL18, and CCL2, with the latter showing the highest correlation with treatment time (Pearson’s r > 0.95). Cell culture media incubated with gas plasma-treated composite chips and added to cells thereafter could not replicate the effects, pointing to the potential that surface modifications elicited the findings. In conclusion, our data suggest that gas plasma treatment modifies composite material surfaces to a certain extent, leading to measurable but overall modest biological effects.

Cold Plasma Irradiation Attenuates Atopic Dermatitis via Enhancing HIF-1α-Induced MANF Transcription Expression

Cold atmospheric plasma has been widely applied in medical treatment clinically, especially skin diseases. However, the mechanism of cold atmospheric plasma on the treatment of skin diseases is still undefined. In this study, dinitrofluorobenzene-induced atopic dermatitis mice model was constructed. Cold atmospheric plasma was able to decrease skin cells apoptosis, relieve skin inflammation, ER stress and oxidative stress caused by dinitrofluorobenzene stimulation, which was mediated by cold atmospheric plasma-induced MANF expression. In terms of mechanism, hypoxia-inducible factor-1α expression was increased intracellularly after cold atmospheric plasma treatment, which further bound to the promoter region of manf gene and enhanced MANF transcriptional expression. This study reveals that cold atmospheric plasma has a positive effect on atopic dermatitis treatment, also demonstrates the regulatory mechanism of cold atmospheric plasma on MANF expression via HIF-1α, which indicates the potential medical application of cold atmospheric plasma for atopic dermatitis treatment.

Novel dual-functional implants via oxygen non-thermal plasma and quaternary ammonium to promote osteogenesis and combat infections

OBJECTIVE

Implant-related infections are a primary reason for implant failures that affect millions of patients. It is of paramount importance to develop novel implants that possess the dual functions of osteogenesis-promotion and antibacterial activity. The objectives of this study were to: (1) develop novel dual-functional titanium (Ti) implants by combining oxygen non-thermal plasma and covalent bonding of antibacterial organosilicon quaternary ammonium monomers; (2) investigate the physicochemical properties, bioactivity and antibacterial effects of the modified implants for the first time.

METHODS

Surface characteristics of the modified Ti surfaces were tested. Adherence and viability of rat bone marrow-derived stem cells (rBMSCs) on the surface were evaluated. Metabolic activity of biofilm on the surfaces were measured. The stability of the dual-function after 5000 thermal cycles was also evaluated.

RESULTS

The presence of chemical bonding between Ti and organosilicon monomers demonstrated covalent immobilization of the antibacterial agents. The water contact angle of the treated Ti surfaces decreased from 70.98 ± 3.68° to 59.86 ± 4.91°. The adhesion and proliferation of rBMSCs on the modified Ti were increased by 40%, compared to control group (P < 0.05). The metabolic level of biofilms on modified Ti were reduced by more than half, compared to control (P < 0.05). The modified Ti implants exhibited cell-promotion and antibacterial stability after thermal cycles.

SIGNIFICANCE

The new dual-functional Ti implant is promising to promote osteogenesis while simultaneously preventing infections. Furthermore, the novel surface modification and processing methods have applicability to enhancing a wide range of other implants to improve bioactivity and combat infections.

Medical gas plasma-stimulated wound healing: Evidence and mechanisms

Defective wound healing poses a significant burden on patients and healthcare systems. In recent years, a novel reactive oxygen and nitrogen species (ROS/RNS) based therapy has received considerable attention among dermatologists for targeting chronic wounds. The multifaceted ROS/RNS are generated using gas plasma technology, a partially ionized gas operated at body temperature. This review integrates preclinical and clinical evidence into a set of working hypotheses mainly based on redox processes aiding in elucidating the mechanisms of action and optimizing gas plasmas for therapeutic purposes. These hypotheses include increased wound tissue oxygenation and vascularization, amplified apoptosis of senescent cells, redox signaling, and augmented microbial inactivation. Instead of a dominant role of a single effector, it is proposed that all mechanisms act in concert in gas plasma-stimulated healing, rationalizing the use of this technology in therapy-resistant wounds. Finally, addressable current challenges and future concepts are outlined, which may further promote the clinical utilization, efficacy, and safety of gas plasma technology in wound care in the future.

Inactivation of Dermatophytes Causing Onychomycosis Using Non-Thermal Plasma as a Prerequisite for Therapy

Following our previous study of the therapy of onychomycosis by non-thermal plasma (NTP) and nail hygiene and to obtain some prerequisite data of dermatophytes sensitivity, the dynamics of those inactivation by NTP plasma was monitored for various strains of Trichophyton iterdigitale, Trichophyton benhamiae, Trichophyton rubrum, and Microsporum canis. Three strains of each species on agar plates were exposed with plasma produced by a DC corona discharge in the point-to-ring arrangement in various time intervals. Although all strains were sufficiently sensitive to plasma action, significant differences were observed in their sensitivity and inactivation dynamics. These differences did not correlate with the species classification of individual strains, but could be assigned to four arbitrarily created types of strain response to NTP according to their sensitivity. These results indicate that the sensitivity to plasma is not an inherent property of the fungal species, but varies from strain to strain.

Non-thermal plasma application enhances the recovery of transected sciatic nerves in rats

This experimental research aimed to investigate the effects of non-thermal plasma on nerve regeneration after transected nerve damage using the sciatic nerve in Wistar albino (A) rats. The experiments were performed on 27 Wistar A rats. The rats underwent surgery for right sciatic nerve exposure and were divided into three groups (each group, n = 9) according to sciatic nerve transected injury (SNTI) and non-thermal plasma application: a non-nerve damage (non-ND) group, a only nerve damage without non-thermal plasma application (ND) group, and a nerve damage with non-thermal plasma application (ND + NTP) group. Subsequent to SNTI and immediate suture, non-thermal plasma was administered three times per week for eight weeks. Evaluation for functional recovery was performed using the static sciatic index measured over the full treatment period of eight weeks. The sciatic nerve specimens were obtained after euthanasia and third day from the last non-thermal plasma application. The sciatic nerve tissues were subjected to histological analysis. Behavior analysis presented that the ND + NTP group showed improved static sciatic index compared with the nerve damage group. Histopathological findings demonstrated that the ND + NTP group had more dense Schwann cells and well-established continuity of nerve fibers, greater than the nerve damage group. Immunohistochemistry showed that the ND + NTP group had increased levels of markers for microtubule-associated protein 2 (MAP2), tau, S100 calcium-binding protein B, and neurofilament-200 and regulated the overexpression of CD68 and MAP2. These results indicated that non-thermal plasma enhanced the motor function and restored the neuronal structure by accelerating myelination and axonal regeneration. Additionally, non-thermal plasma was confirmed to have a positive effect on the recovery of SNTI in rats.

Recent Progress in Applications of Non-Thermal Plasma for Water Purification, Bio-Sterilization, and Decontamination

Various reactive oxygen and nitrogen species are accompanied by electrons, ultra-violet (UV) radiation, ions, photons, and electric fields in non-thermal atmospheric pressure plasma. Plasma technology is already used in diverse fields, such as biomedicine, dentistry, agriculture, ozone generation, chemical synthesis, surface treatment, and coating. Non-thermal atmospheric pressure plasma is also considered a promising technology in environmental pollution control. The degradation of organic and inorganic pollutants will be massively advanced by plasma-generated reactive species. Various investigations on the use of non-thermal atmospheric pressure plasma technology for organic wastewater purification have already been performed, and advancements are continuing to be made in this area. This work provides a critical review of the ongoing improvements related to the use of non-thermal plasma in wastewater control and outlines the operational principle, standards, parameters, and boundaries with a special focus on the degradation of organic compounds in wastewater treatment.

The Effects of Cold Atmospheric Pressure Plasma on Germination Parameters, Enzyme Activities and Induction of DNA Damage in Barley

Climate change, environmental pollution and pathogen resistance to available chemical agents are part of the problems that the food industry has to face in order to ensure healthy food for people and livestock. One of the promising solutions to these problems is the use of cold atmospheric pressure plasma (CAPP). Plasma is suitable for efficient surface decontamination of seeds and food products, germination enhancement and obtaining higher yields in agricultural production. However, the plasma effects vary due to plasma source, treatment conditions and seed type. In our study, we tried to find the proper conditions for treatment of barley grains by diffuse coplanar surface barrier discharge, in which positive effects of CAPP, such as enhanced germination or decontamination effects, would be maximized and harmful effects, such as oxidation and genotoxic potential, minimized. Besides germination parameters, we evaluated DNA damage and activities of various germination and antioxidant enzymes in barley seedlings. Plasma exposure resulted in changes in germination parameters and enzyme activities. Longer exposures had also genotoxic effects. As such, our findings indicate that appropriate plasma exposure conditions need to be carefully optimized in order to preserve germination, oxidation balance and genome stability, should CAPP be used in agricultural practice.

Cold Atmospheric Plasma: A New Strategy Based Primarily on Oxidative Stress for Osteosarcoma Therapy

Osteosarcoma is the most common primary bone tumor, and its first line of treatment presents a high failure rate. The 5-year survival for children and teenagers with osteosarcoma is 70% (if diagnosed before it has metastasized) or 20% (if spread at the time of diagnosis), stressing the need for novel therapies. Recently, cold atmospheric plasmas (ionized gases consisting of UV-Vis radiation, electromagnetic fields and a great variety of reactive species) and plasma-treated liquids have been shown to have the potential to selectively eliminate cancer cells in different tumors through an oxidative stress-dependent mechanism. In this work, we review the current state of the art in cold plasma therapy for osteosarcoma. Specifically, we emphasize the mechanisms unveiled thus far regarding the action of plasmas on osteosarcoma. Finally, we review current and potential future approaches, emphasizing the most critical challenges for the development of osteosarcoma therapies based on this emerging technique.

Cold Atmospheric Pressure Plasma (CAP) as a New Tool for the Management of Vulva Cancer and Vulvar Premalignant Lesions in Gynaecological Oncology

Vulvar cancer (VC) is a specific form of malignancy accounting for 5–6% of all gynaecologic malignancies. Although VC occurs most commonly in women after 60 years of age, disease incidence has risen progressively in premenopausal women in recent decades. VC demonstrates particular features requiring well-adapted therapeutic approaches to avoid potential treatment-related complications. Significant improvements in disease-free survival and overall survival rates for patients diagnosed with post-stage I disease have been achieved by implementing a combination therapy consisting of radical surgical resection, systemic chemotherapy and/or radiotherapy. Achieving local control remains challenging. However, mostly due to specific anatomical conditions, the need for comprehensive surgical reconstruction and frequent post-operative healing complications. Novel therapeutic tools better adapted to VC particularities are essential for improving individual outcomes. To this end, cold atmospheric plasma (CAP) treatment is a promising option for VC, and is particularly appropriate for the local treatment of dysplastic lesions, early intraepithelial cancer, and invasive tumours. In addition, CAP also helps reduce inflammatory complications and improve wound healing. The application of CAP may realise either directly or indirectly utilising nanoparticle technologies. CAP has demonstrated remarkable treatment benefits for several malignant conditions, and has created new medical fields, such as “plasma medicine” and “plasma oncology”. This article highlights the benefits of CAP for the treatment of VC, VC pre-stages, and postsurgical wound complications. There has not yet been a published report of CAP on vulvar cancer cells, and so this review summarises the progress made in gynaecological oncology and in other cancers, and promotes an important, understudied area for future research. The paradigm shift from reactive to predictive, preventive and personalised medical approaches in overall VC management is also considered.

Effects of cold atmospheric pressure plasma jet on human apical papilla cell proliferation, mineralization, and attachment

OBJECTIVES

To investigate the direct effects of cold atmospheric pressure plasma jet on cell proliferation and mineralization on human apical papilla cells and its indirect effect on cell attachment on plasma-treated dentin.

MATERIALS AND METHODS

Plasma was directly applied to cell culture for various durations. Cell proliferation was evaluated using AlamarBlue® assay. Mineralization was assessed using Alizarin Red S staining after 14 and 21 days. The cell attachment to plasma-treated dentin surface was evaluated using an ex vivo immature tooth model, and the protocols varied based on root canal irrigants (NSS or 17% EDTA), the durations of plasma application (0, 30, or 60 s), and the different positions of the plasma needle (coronal or middle). The attached cells were visualized using the immunofluorescence staining and the positive-staining cells were counted.

RESULTS

There was no difference in the cell proliferation between the untreated and plasma-treated cells. However, the plasma-treated cells tended to have lower levels of calcium deposition, especially after the 60-s plasma application (p < 0.05). Finally, significantly greater numbers of attached cells were shown when NSS was combined with plasma treatment when compared to the untreated cells (p < 0.05), whereas no difference was observed when EDTA was used as the irrigant.

CONCLUSIONS

Plasma might disturb the mineralization of the cells. Interestingly, the dentin conditioning process using a plasma jet with NSS irrigation may enhance cell attachment.

CLINICAL RELEVANCE

Cold atmospheric pressure plasma jet may be an alternative treatment in regenerative endodontic procedures in order to improve cell attachment in the root canal system.

Cold atmospheric pressure (physical) plasma in dermatology: where are we today?

Cold atmospheric pressure plasma is physical plasma (essentially ionized gas) created at room temperature and atmospheric pressure, and it has complex effects on cells, tissues, and living organisms. These effects are studied extensively for medical and dermatological use. This article reviews current achievements and new trends in clinical dermatological cold plasma research, discusses the basics of plasma physics and plasma engineering, and describes the most important areas of laboratory plasma research to provide a well-rounded understanding of the nature, present applications, and future promise of this exciting, emerging technology.

Plasma Medicine: A Field of Applied Redox Biology

Plasma medicine comprises the application of physical plasma directly on or in the human body for therapeutic purposes. Three most important basic plasma effects are relevant for medical applications: i) inactivation of a broad spectrum of microorganisms, including multidrug-resistant pathogens, ii) stimulation of cell proliferation and angiogenesis with lower plasma treatment intensity, and iii) inactivation of cells by initialization of cell death with higher plasma treatment intensity, above all in cancer cells. Based on own published results as well as on monitoring of relevant literature the aim of this topical review is to summarize the state of the art in plasma medicine and connect it to redox biology. One of the most important results of basic research in plasma medicine is the insight that biological plasma effects are mainly mediated via reactive oxygen and nitrogen species influencing cellular redox-regulated processes. Plasma medicine can be considered a field of applied redox biology.

Investigation of Power Transmission of a Helium Plasma Jet to Different Dielectric Targets Considering Operating Modes

The interaction of an atmospheric pressure plasma jet with different dielectric surfaces is investigated using a setup of two ring electrodes around a ceramic capillary. In this study, in addition to electrical measurement methods such as the determination of voltage and current, special emphasis was placed on the power measurements at the electrodes and the effluent. The power dissipation is correlated with Fourier-transform infrared (FTIR) absorption spectroscopy measurements of O3 and NO2 densities. The results show the correlation between the dielectric constant and the dissipated power at the target. The ratio between power dissipation at the grounded ring electrode and the grounded surface shows an increase with increasing dielectric constant of the target. A correlation of the results with bacteria, tissue and water as envisaged dielectric targets shows four times the power dissipation at the treatment spot between bacteria and tissue.

Decolorization effect and related mechanism of atmospheric pressure plasma jet on Eriochrome Black T

In this study, Eriochrome Black T (EBT) in water was decolorized by means of argon atmospheric pressure plasma jet (APPJ), which showed great decolorization performance. The results showed that the relatively high decolorization rate (approximately 80%) was obtained after plasma treatment for 6 min. Changes to some reactive oxygen and nitrogen species (RONS) in the liquid phase were detected. The contents of peroxide, HO·, O₂ ^-·, and NO· in the plasma-treated EBT solution were much less than those in the activated water. The roles of H₂O₂ and HO· in the decolorization of EBT solution were explored by evaluating the effects of their scavengers, and by exploring the direct effect of H₂O₂. The results indicated that reactive oxygen species (ROS), especially HO· and O₂ ^-·, played significant roles in the decolorization of the EBT solution. Analysis of degradation by-products indicated that plasma discharge could destroy the azo bond first and gradually break the aromatic rings of EBT molecules into small molecular compounds.

Plasma Farming: Non-Thermal Dielectric Barrier Discharge Plasma Technology for Improving the Growth of Soybean Sprouts and Chickens

Non-thermal dielectric barrier discharge (DBD) plasma is an innovative and emerging field combining plasma physics, life science and clinical medicine for a wide-range of biological applications. Plasma techniques are applied in treating surfaces, materials or devices to realize specific qualities for subsequent special medical applications, plant seeds to improve the production and quality of crops, and living cells or tissues to realize therapeutic effects. Several studies that are summarized within this review show that non-thermal DBD plasma technique has potential biological applications in soybean sprout growth, chicken embryonic development and postnatal growth rate, and even male chicken reproductive capacity. The current developments in the non-thermal DBD plasma technique may be beneficial to improve plant and poultry productivity.

Effects and safety of atmospheric low-temperature plasma on bacterial reduction in chronic wounds and wound size reduction: A systematic review and meta-analysis

The use of atmospheric low‐temperature plasma (AP) on chronic wounds and its effect on microbial bioburden in open wounds has not been explored with a systematic review and meta‐analysis. PRISMA guidelines were followed and PubMed, Embase, CENTRAL, and CINAHL databases searched for randomised controlled trials (RCTs), which compared AP with no AP for the management of open, chronic wounds. The primary outcomes of reduction of bioburden or wound size were included. Meta‐analyses were performed; odds ratio (OR) and 95% confidence intervals (CIs) were extracted and pooled in a random effects model.

Four RCTs investigated the effect of AP on chronic wound healing. Chronic wounds treated with AP did not show a significant improvement in healing (AP vs control: OR = 1.46; 95% CI = 0.89‐2.38; P = 0.13). Five further RCTs investigated the reduction of bioburden in wounds, but AP demonstrated no significant reduction of bioburden (AP vs control: OR = 0.85; 95% CI = 0.45‐1.62; P = 0.63). All nine RCTs recorded the presence of any severe adverse events (SAEs) in the 268 patients studied, with only one unrelated SAE identified in each group (AP vs control: OR = 1.00; 95% CI = 0.05‐19.96; P = 1.00). Use of AP in wound care is safe, but the retrieved evidence and meta‐analysis show that there is no clinical benefit of AP in chronic open wounds using currently available AP device settings.