Plasma polymer nanoparticles (pp-NPs) are relatively easy to produce by plasma-based gas aggregation sources. However, as experimentally evidenced in this study for the case of C:H:N:O pp-NPs, pp-NPs are unlike metal/metal oxide nanoparticles prone to reflection from the substrate if they hit it with too high a speed. This may result in little or no deposition rate even though the nanoparticle beam is very intense. As is shown, the deposition of pp-NPs can be promoted either by the adjustment of their speed before they reach the substrate or by a proper selection of a substrate. Concerning the latter, enhanced capturing of pp-NPs was observed on structured or liquid substrates.

Cold atmospheric plasma (CAP), as a noninvasive technology, has shown promise in dentistry as it might successfully treat various oral conditions. The antimicrobial capacity of CAP has been proven and it is effective in reducing the main microorganisms responsible for oral infections. Furthermore, CAP has also been explored in the field of tissue regeneration with a great response from both soft and hard tissue. The surface modification ability of CAP is another area of interest, revealing a potential improvement in the osseointegration of dental implants. Additionally, there are other areas within dentistry that have studied the use of CAP, such as surface disinfection, bleaching, and cavity preparation.

Antibacterial properties and chemical changes of two culture media, Dulbecco's Modified Eagle Medium (DMEM) and Roswell Park Memorial Institute (RPMI), treated by RF-driven He/O2 plasma jet, were studied using various chemical diagnostics and assessing Escherichia coli inactivation. The antibacterial effect increased with the plasma treatment time and was stronger in RPMI than in DMEM. Formation of organic mono- and dichloramines of amino acids in DMEM/RPMI by hypochlorite produced by the reaction of plasma-generated O atoms with Cl− ions present in culture media were the major causes of the biocidal activity. This behavior was attributed to the action of tertiary chemical products formed by the decay of organic dichloramines. The thiobarbituric acid assay revealed malondialdehyde formation from glucose oxidation as the major component of the media.

This short review focuses on in situ product removal as a method to improve the energy efficiency and product yield of plasma-based conversions. After recapping the advantages of in situ separations in thermal-catalytic processes, different strategies for in situ product removal for plasma-based conversions are discussed. Advantages and challenges are discussed regarding four strategies, that is, absorption and adsorption using solids, use of sacrificial reactants, separation with ceramic dense membranes, and product removal in the liquid phase.

The current trends that incorporate artificial intelligence (AI) and medicine have created new opportunities for improvement in both early diagnosis and treatment of diseases. In this framework, AI might also have the potential to significantly revolutionize the way we approach the field of plasma medicine, an area that is quickly growing and uses cold atmospheric plasma (CAP) to address a variety of medical conditions. Plasma medicine offers promising therapeutic alternatives for conditions widely ranging from cancer treatment to wound healing and antimicrobial applications, but the complexity of the plasma sources and the huge number of parameters may be overwhelming for the determination of underlying mechanisms and for understanding the effect of the source. This is where AI steps in, to provide strong tools for modeling, evaluating, and controlling CAPs. By harnessing the power of AI, researchers in the plasma medicine area, are now able to evaluate massive volumes of data, enhance their treatment protocols, and predict treatment results with a level of precision never possible before. Hereby, we emphasized the potential and further utilization of AI in plasma medicine in light of the fascinating and recent developments in this cooperation. New opportunities are encouraging, but potential limitations, ethical issues, model transparency, and generalizability should be considered. Regardless, the possibilities are endless, and the future of plasma medicine is looking brighter than ever with the implementation of AI.

A surface dielectric barrier discharge reactor was applied in the removal of oxygen traces from coke oven gas (COG), to which toluene was added as a model hydrocarbon contaminant. The adverse effect of toluene on O2 conversion was observed in a H2/N2/O2 mixture, while in synthetic COG consisting of H2, CH4, N2, CO, CO2, and O2, it remained unchanged. Online gas chromatography (GC) showed that the reactivity of toluene is mainly driven by H2/N2/O2. The accumulated residue was dissolved and analyzed by GC coupled with mass spectrometry. The identified reaction products suggest that toluene undergoes ring-opening and functionalization.

Toward hydrogen production from renewable sources, coreforming of dilute bioethanol (5 mol% ethanol) and methane using gliding arc discharge warm plasma is reported. For warm plasma alone, increases in methane to ethanol ratio and specific energy input lead to improving hydrogen yield, but low energy efficiency (<60%). The warm plasma coupled with Ni/CeO2/Al2O3 catalyst in a heat-insulation reactor achieves an energy efficiency of 80%, but the large axial-temperature drop of the catalyst bed causes low conversions. Therefore, additional heating is provided to maintain the catalyst bed temperature. Under optimal conditions, total carbon conversion of 97% and hydrogen yield of 78% are achieved with an energy cost of 1.16 kWh/Nm3 and energy efficiency of 85%.

Recently developed excitation frequency-controlled cold atmospheric pressure plasma has shown its efficacy in producing tunable effects with different excitation frequencies in terms of reactive species generation and cancer cell death. This study investigates the electron number density of plasma produced at 11 kHz excitation from stark broadened Hα line, discharge characteristics through simultaneous recording of voltage-current signals, and high-speed images of the discharge zone. Malignant breast cancer cells (MCF-7) and nonmalignant breast cells (MCF-10A) were used in selectivity experiments. Proliferation and clonogenic assays revealed selective death of cancer cells. DNA damage and DNA repair kinetics were studied using time-dependent γ-H2AX foci formation assessment and the selective killing of cancerous cells was established for the 60 s of plasma treatment.

A low-cost plasma-chemical hybrid process (PCHP) is proposed for simultaneous NOx and SOx treatment. PCHP can be integrated into existing desulfurization reactors by combining plasma oxidation and chemical reduction. PCHP is applied to glass melting furnace emissions with limited denitration technology, achieving higher removal efficiencies of NO, NOx, and SO2 (43%, 38%, and 28%, respectively) by optimizing reductant spray and installation angles. PCHP also improves fuel consumption, with a 0.04 increase in air ratio reducing energy consumption by 3.6 kL/day (equivalent to 6.6 t(CO2)/day reduction). In addition, PCHP allows for the collection and reuse of treated SO2 as sodium sulfate particles, making it a suitable aftertreatment technology for glass manufacturing exhaust.

The plasma in contact with liquids has led to various novel applications such as plasma biomedicine, material synthesis, and so on. However, the phenomenon of evaporation under plasma treatment and its impact on plasma–liquid interactions has a limited understanding. In this study, the spatially and temporally resolved behavior of water vapor production and its induced influences on plasma properties and gaseous chemistry were studied in detail in an atmospheric pressure pin-to-water pulsed He discharge. Diagnostic methods such as laser-induced fluorescence (LIF) and high-resolution optical emission spectroscopy (OES) were applied to determine the water vapor and OH radical densities, as well as key plasma parameters such as the gas temperature and electron density. It shows that the physicochemical properties of plasma vary among different discharge regions due to evaporation behavior stimulated during the pulsed discharge-on phase. In addition, using simulation based on the experimental data, the mechanisms of how water vapor affects the observed spatiotemporal behaviors of OH radicals in different discharge regions are understood. Compared to the pin-anode and liquid-cathode sheath regions, proper electron parameters such as density and temperature, as well as water vapor density in the plasma-positive column, significantly enhance the production of reactive OH radical through the dominant path of electron-stimulated H2O dissociation. However, higher levels of electron parameters in the intense discharge region near the positive-pin boundary enhance OH dissociation and finally result in the hollow distribution of OH density. From the global kinetic plasma simulation, the production of reactive hydroxide species playing key roles in plasma medicine treatments, such as O, H, HO2, H2O2, and hydrated ions including H+(H2O)4 and H+(H2O)5, are promoted noticeably as a result of the enhanced water evaporation process.

A dielectric barrier discharge with falling liquid film was used to degrade the antibiotics amoxicillin and sulfamethoxazole in water. The antibiotic concentrations decrease exponentially during plasma treatment and have similar half-life time, in the range 4–9 min. By increasing the discharge power (9.1–20.2 W), faster removal of the contaminants is obtained, but the energy efficiency remains almost the same, 3–4 g/kWh at 50%. Oxygen considerably improves the energy yield by a factor of two as compared with air, due to more effective formation of reactive oxygen species. It was found that the degradation of antibiotics in mixture essentially depends on the overall initial concentration, this behavior being attributed to the similar reactivity of the two investigated compounds.

Plasma polymers (PPs) can easily modify material surfaces to improve their bio-applicability due to match-made surface-free energy and functionality. However, cell adhesion to PPs typically composed of various functional groups has not yet been fully understood. We explain the origin of strong resistance to trypsin treatment previously noted for nonendothelial cells on amine PPs. It is caused mainly by nonspecific adhesion of negatively charged parts of transmembrane proteins to the positively charged amine PP surface, enabled by thin glycocalyx. However, endothelial cells are bound primarily by their thick, negatively charged glycocalyx and sporadically by integrins in kinetic traps, both cleaved by trypsin. Cell scratching by atomic force microscopy tip confirmed the correlation of trypsin resistance to the strength of cell adhesion.

Plasma polymers from glycidol vapors are of interest for direct covalent grafting of molecules bearing amine or thiol groups. The question of whether pulsed plasma operation might lead to a higher surface density of epoxide groups and a higher density of grafted molecules is studied using the antifungal drug caspofungin. X-ray photoelectron spectroscopy and Time of flight-secondary ions mass spectrometry analysis followed by caspofungin grafting revealed that both continuous wave and pulsed plasmas led to surface epoxides but with higher densities upon pulsing. Investigations into stability suggested that glycidol plasma polymer coatings were still able to immobilize caspofungin after 2 years of storage, making them suitable for applications where grafting of molecules needs to be done immediately before usage of a device.

Here, we report on the optimized design for the needle-to-plane electrode geometry to generate the atmospheric air streamer-to-spark transition discharge over the surface of the water at the pulsed voltage of ±30 kV. This design contributes to an increase in the electric field at the head of air surface streamers during their propagation, which eventually evolves into a spark over water. The length of streamer-to-spark transition discharge is up to 150 mm, which is affected by the conductivity of water, the electrode polarity, and the horizontal distance between the high-voltage pin electrode and the grounded plane electrode. Water is quickly activated by the streamer-to-spark transition discharge, which can be attributed to the dissolution of plasma-generated species including long-lived and short-lived reactive species in the gas phase. Compared to the negative streamer-to-spark transition discharge, the positive one is more effective in increasing the biological reactivity of water. Analysis indicates that the positive ions in the positive surface streamers can dissolve in water, which contributes to the formation of reactive species in water, thus an increase in the biological reactivity of water.

Lower flow rates of precursor molecules are favorable for the synthesis of thin-film materials using nonthermal plasma at a higher degree of dissociation and sufficiently high deposition rate. These deposition conditions can be used for both continuous wave (CW) and pulsed plasmas and result in higher consumption of precursor molecules, which is beneficial for industrial applications due to cost reduction. A wider range of power can be used to control the chemical and physical properties of thin-film materials based on power-dependent plasma chemistry. Hydrogenated amorphous silicon carbide films deposited in CW and pulsed plasma are used as an example. The different kinetics of film growth and the role of self-bias voltage in both types of plasma are discussed.

Nowadays, the majority of the processes used to sterilize disposable medical devices have several drawbacks in terms of safety, energy consumption, and costs. In this work, a sterilization method based on an indirect nonthermal plasma treatment is presented. The main advantages of this method are low environmental impact, absence of harmful chemical compounds' storage, and backward compatibility relative to production, sterilization, and shipping chain. The sterilization of disposable devices, enclosed inside their protective packaging, is achieved by exploiting reactive species produced by a Dielectric Barrier Discharge plasma reactor. Various devices have been subjected to a 2-h treatment, achieving complete sterilization based on USP and EU-PHARMA protocols. Pretreatment of carton packaging has been necessary to guarantee a complete sterilization process.

Plasma-activated solutions (PAS) are attracting attention in biomedicine, however their complexity necessitates a greater understanding of both the plasma activation process and the selected starting solution. Here, five solutions, including deionized water, saline, PB, PBS, and RPMI 1640, were treated to investigate the physicochemical properties and anticancer effects. The findings show that the different solutions largely affected the gas–liquid interaction reactions and the color penetration distribution of H2O2 and NO2−. The anticancer effects are in the order of DI > PB≈saline> PBS > RPMI 1640, attributed to the important role of H2O2 and NO2− in inactivating cancer cells. This study provides insights into designing and applying PAS in practical anticancer therapy.

Fundamental and applied research on plasma-treated liquids for biomedical applications was boosted in the last few years, dictated by their advantages with respect to direct treatments. However, often, the lack of consistent analysis at a molecular level of these liquids, and of the processes used to produce them, have raised doubts of their usefulness in the clinic. The aim of this article is to critically discuss some basic aspects related to the use of plasma-treated liquids in medicine, with a focus on their chemical composition. We analyze the main liquids used in the field, how they are affected by non-thermal plasmas, and the possibility to replicate them without plasma treatment.

Aging (or “hydrophobic recovery”) of plasma-modified polymer surfaces has been known and documented in the literature over several decades; to the best of our knowledge, the present study appears to be the first in which this is done for two vastly different rough surface structures: (i) electrospun nanofibrous (NF) mats, and (ii) flat films (FF), for three polymers of well-documented interest in biotechnological applications: poly(lactic acid); poly(urethane); and poly(caprolactone). Two different plasma treatments are applied: low-pressure (LP) radio-frequency (rf) glow discharges in flows of O2 and NH3 under mild power conditions. Measured time-dependent surface compositions (from X-ray photoelectron spectroscopy survey spectra) and water contact angles (WCA) were found to tend toward asymptotic limiting values after ca. 30 days of storage in clean air, as previously reported by these and other authors. An entirely novel aspect of this work is to examine and compare time-dependent WCA behaviors of NF and FF samples in terms of Wenzel (W) and Cassie-Baxter (C-B) model behaviors, including possible transitions from C-B to W and their interpretation.

The potential antitumor application of low-temperature plasma (LTP) in immunotherapy has attracted wide attention from researchers. The induction of immunogenic cell death (ICD) is one of the possible mechanisms underlying this event. In this work, the immunogenicity of B16F10 melanoma cells treated with direct and indirect LTP protocols was investigated. The results revealed the concentrations of H2O2, NO, and NO2− increased as LTP treatment time was longer, while the cell viability decreased. By comparison, the direct treatment induced a stronger expression of ICD markers. In vivo, the LTP-treated B16F10 reduced tumor burden in C57BL/6 mice. This study demonstrated both direct and indirect LTP treatments triggered immunogenic cell death and were expected to provide an effective immunotherapy strategy.