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Plasma-activated water can efficiently inactivate pathogenic microorganisms and is considered to be a potent disinfectant in the medical, food, and agricultural industries. In this study, the air discharged by the gliding arc was mixed with different gases including O2, ambient air, synthetic air, and N2 at different flow rates to produce the activated gases, which were then activated gases were inducted into saline to prepare plasma-activated saline (PAS). The gaseous reactive species in the activated gases were composed of NO, NO2, and N2O5 and the aqueous reactive species in the PAS included H2O2, NO2−, NO3–, ⋅ OH , and 1O2 with different intensities, while the inactivation effects of the PAS also varied with the type and the flow rates of the mixed gases in the activated gases. The inactivation effects of the PAS treated by the discharged air mixed with O2, ambient air, and synthetic air started to become weak after 3 h placement. Scavenger analysis demonstrated that the 1O2 played a critical role in the inactivation process. This study indicated that air discharged by the gliding arc mixed with different gases could regulate the reactive species and the biological effects of PAS, providing insight into the preparation of PAS applied for disinfection. [ABSTRACT FROM AUTHOR]

Oral diseases stemming from oral pathogenic bacteria pose a significant global health concern, and current methods for managing these pathogens have limitations. Plasma‐activated water (PAW), containing various reactive species, emerges as a promising disinfectant with impressive inactivation capabilities. In this study, PAW prepared by mixed‐mode plasma‐activated gases was applied to inactivate oral pathogenic bacteria, including Streptococcus mutans and Porphyromonas gingivalis. The PAW could reduce more than 6.1‐log10 planktonic bacteria and 4.1‐log10 bacteria within biofilm, respectively, and PAW treatment of planktonic bacteria effectively inhibited biofilm formation. Compared to chlorhexidine, PAW exhibited superior inactivation effects in both planktonic bacteria and biofilm. This study presented a potent strategy for bacteria eradication to reduce the incidence of oral diseases. [ABSTRACT FROM AUTHOR]

Cold‐chain transport is a crucial cross‐regional transmission pathway for severe acute respiratory syndrome coronavirus 2 and other microorganisms. In this study, the mode‐combination method is adopted for sterilization in a 1.138 m3 freezer by mixing effluent gases of NOx and O3 mode air discharges. The mixed gas can effectively inactivate Staphylococcus aureus in 10 mm ice within 3 h, which significantly surpasses O3 gas. Moreover, the inactivation effect of the mixed gas can penetrate deep into ice, contrasting with the surface effect of O3 gas. This disparity is linked to the difference in penetration depth of strong oxidizing long‐lived reactive species. This study validates the sterilization efficacy of cold atmospheric plasma in practical cold‐chain environment, critical for curbing infectious disease transmission. [ABSTRACT FROM AUTHOR]

Plasma‐based technology has been widely applied in the biomedicine, agriculture, and environmental fields. In this study, a new application mode, namely plasma‐activated nebulized mist (PANM) was proposed. The saline was nebulized by the plasma‐activated air to form a mist, and the inactivation effects on Pseudomonas aeruginosa were analyzed based on the simulated respiratory tract. The PANM through the simulated trachea with different lengths or diameters, and the branched once or twice simulated respiratory tract exhibited effective inactivation effects. The PANM through the combined simulated trachea and pig trachea could also inactivate the bacteria on the inner wall of the pig trachea. This study supplied a potent alternative to antibiotics for the treatment of respiratory tract infections. [ABSTRACT FROM AUTHOR]

A continuous risk from microbial infections poses a major environmental and public health challenge. As an emerging strategy for inhibiting bacterial infections, plasma‐activated water (PAW) has proved to be highly effective, environmental‐friendly, and non‐drug resistant to a broad range of microorganisms. However, the relatively short lifetime of reactive oxygen and nitrogen species (RONS) and the high spreadability of liquid PAW inevitably limit its real‐life applications. In this study, plasma‐activated hydrogel (PAH) is developed to act as reactive species carrier that allow good storage and controlled slow‐release of RONS to achieve long‐term antibacterial effects. Three hydrogel materials, including hydroxyethyl cellulose (HEC), carbomer 940 (Carbomer), and acryloyldimethylammonium taurate/VP copolymer (AVC) are selected, and their antibacterial performances under different plasma activation conditions are investigated. It is shown that the composition of the gels plays the key role in determining their biochemical functions after the plasma activation. The antimicrobial performance of AVC is much better than that of PAW and the other two hydrogels, along with the excellent stability to maintain the antimicrobial activity for more than 14 days. The revealed mechanism of the antibacterial ability of the PAH identifies the unique combination of short‐lived species (1O2, ∙OH, ONOO− and O2−) stored in hydrogels. Overall, this study demonstrates the efficacy and reveals the mechanisms of the PAH as an effective and long‐term disinfectant capable of delivering and preserving antibacterial chemistries for biomedical applications. [ABSTRACT FROM AUTHOR]

Gliding arc is a promising plasma technology for water activation due to its high energy efficiency for producing reactive nitrogen species (RNS), which is believed as the key agent for the sustained bactericidal effect of plasma-activated water (PAW). Nitric oxide (NO) is the major product of gliding arc and also widely exists in PAW, but the production mechanism of aqueous NO and its role in sterilization have been little investigated before. In this paper, NO-rich plasma effluent gas is produced by gliding arc discharge and introduced into water to produce PAW. The concentrations of gaseous and aqueous reactive species are detected, which decrease with the increasing air flowrate of the gliding arc. To clarify the contribution of plasma-induced RNS on water activation, the NO + air mixed gas is used to simulate the plasma effluent gas, and the results show that the two gases have similar gaseous composition and aqueous NO yield. Compared with the NO + Ar mixed gas with the same NO proportion, the NO + air mixed gas produces much more aqueous NO, implying that the presence of O2 significantly enhances the production of aqueous NO. The sterilization experiments demonstrate the key role of aqueous NO in sterilization, but an acidic environment is necessary for aqueous NO to achieve a potent bactericidal effect. [ABSTRACT FROM AUTHOR]

Gliding arc is a promising plasma technology for water activation due to its high energy efficiency for producing reactive nitrogen species (RNS), which is believed as the key agent for the sustained bactericidal effect of plasma-activated water (PAW). Nitric oxide (NO) is the major product of gliding arc and also widely exists in PAW, but the production mechanism of aqueous NO and its role in sterilization have been little investigated before. In this paper, NO-rich plasma effluent gas is produced by gliding arc discharge and introduced into water to produce PAW. The concentrations of gaseous and aqueous reactive species are detected, which decrease with the increasing air flowrate of the gliding arc. To clarify the contribution of plasma-induced RNS on water activation, the NO + air mixed gas is used to simulate the plasma effluent gas, and the results show that the two gases have similar gaseous composition and aqueous NO yield. Compared with the NO + Ar mixed gas with the same NO proportion, the NO + air mixed gas produces much more aqueous NO, implying that the presence of O2 significantly enhances the production of aqueous NO. The sterilization experiments demonstrate the key role of aqueous NO in sterilization, but an acidic environment is necessary for aqueous NO to achieve a potent bactericidal effect. [ABSTRACT FROM AUTHOR]

Plasma‐activated media (PAM), the product of cold atmospheric plasma (CAP) acting on aqueous media, has similarly strong biological activity and some unique advantages compared with CAP for biomedical targets. However, no reliable PAM‐preparing device with high safety for medical uses has yet been developed, limiting the advancement of PAM clinical trials. Herein, an integrated device for PAM preparation with a maximum yield of 4.8 L/hr is reported in detail. A large‐area CAP is generated by the plasma‐generating module based on the surface dielectric barrier discharge. Several sensors and controllers are applied in this device to stabilize the discharge environment and PAM consistency. In the in vitro experiments, PAM prepared in this device exhibits the bactericidal property of up to 6 logs reduction against various clinical pathogens with multi‐drug resistance. The high bactericidal effect of PAM can be preserved for ∼10 min. After constructing the mice model by cecal ligation and puncture, it is found that the abdominal injection of PAM can effectively relieve sepsis‐induced systemic toxicity and maintain homeostasis, which is mainly attributed to the anti‐infective efficacy of PAM. The third‐party testing confirms that the soaking bactericidal rates of PAM to S. aureus and E. coli are respectively higher than 99.99% and 99.999%, while the acute oral toxicity, skin irritation, and oral genotoxicity of PAM are negligible. This study provides a practical approach for preparing PAM with high reliability, which shows an excellent prospect of clinical applications and commercialization. [ABSTRACT FROM AUTHOR]

Cold atmospheric plasma, a promising technology for cancer therapy, can simultaneously induce electrochemistry, which has been widely demonstrated to be effective against cancer. Herein, the anticancer effects of direct current plasma jets and electrochemical circuit are comparatively studied with similar topological structures and average currents. The cell inactivation patterns formed by plasma and electrochemical treatment (EChT) are disparate, and the inactivation is mainly caused by the emission of charged species, helium flow, in situ OH radical production, or local alkalization. The culture medium treated by EChT exerted no sustained anticancer effect, whereas the medium treated by plasma could maintain a strong effect due to the production of more reactive species, suggesting that the electrochemistry does not dominate the plasma inactivation of cancer cells. [ABSTRACT FROM AUTHOR]

Biofilms formed by multidrug-resistant bacteria are a major cause of hospital-acquired infections. Cold atmospheric-pressure plasma (CAP) is attractive for sterilization, especially to disrupt biofilms formed by multidrug-resistant bacteria. However, the underlying molecular mechanism is not clear. In this study, CAP effectively reduced the living cells in the biofilms formed by methicillin-resistant Staphylococcus aureus, and 6 min treatment with CAP reduced the S. aureus cells in biofilms by 3.5 log10. The treatment with CAP caused the polymerization of SaFtsZ and SaClpP proteins in the S. aureus cells of the biofilms. In vitro analysis demonstrated that recombinant SaFtsZ lost its self-assembly capability, and recombinant SaClpP lost its peptidase activity after 2 min of treatment with CAP. Mass spectrometry showed oxidative modifications of a cluster of peaks differing by 16 Da, 31 Da, 32 Da, 47 Da, 48 Da, 62 Da, and 78 Da, induced by reactive species of CAP. It is speculated that the oxidative damage to proteins in S. aureus cells was induced by CAP, which contributed to the reduction of biofilms. This study elucidates the biological effect of CAP on the proteins in bacterial cells of biofilms and provides a basis for the application of CAP in the disinfection of biofilms. [ABSTRACT FROM AUTHOR]

The airborne microorganisms in the aerosols are one main transmission way of pathogenic microorganisms and therefore inactivation of microorganisms in aerosols could effectively prevent the transmission of pathogenic microorganisms to control epidemics. The mist nebulized by plasma-activated air could effectively inactivate bacteria and could be developed for the sterilization of microorganisms in aerosols. In this study, the plasma-activated nebulized mist (PANM) was applied for the inactivation of microorganisms in aerosols and efficiently inactivated the bacteria, yeast, and viruses in aerosols after 2-min treatment. The PANM treatment caused morphologic changes and damage to the bacteria cells in aerosols. The PANM could also inactivate the microorganisms attached to the surface of the treatment chamber and the bacteria attached to the skin of mice within 6-min treatment. The biosafety assays demonstrated that the PANM treatment exhibited no effects on the behavior, hematological and serum biochemical parameters of blood, and organs from the mice. This study would supply an efficient, broad-spectrum, and safe aerosol sterilization strategy based on plasma technology to prevent the transmission of airborne microorganisms. [Display omitted] • Plasma-activated nebulized mist (PANM) inactivated the microorganisms in aerosols. • PANM also inactivated the microorganisms attached to the surface of the chamber. • PANM treatment caused morphologic changes to the bacterial cells in aerosols. • PANM inactivated the bacteria on the skin of mice and had no side effects on mice. • PANM provided a new strategy for the efficient sterilization of microbial aerosols. [ABSTRACT FROM AUTHOR]

The global pandemic caused by SARS-CoV-2 has lasted two and a half years and the infections caused by the viral contamination are still occurring. Developing efficient disinfection technology is crucial for the current epidemic or infectious diseases caused by other pathogenic microorganisms. Gas plasma can efficiently inactivate different microorganisms, therefore, in this study, a combination of water spray and plasma-activated air was established for the disinfection of pathogenic microorganisms. The combined treatment efficiently inactivated the Omicron-pseudovirus through caused the nitration modification of the spike proteins and also the pathogenic bacteria. The combined treatment was improved with a funnel-shaped nozzle to form a temporary relatively sealed environment for the treatment of the contaminated area. The improved device could efficiently inactivate the Omicron-pseudovirus and bacteria on the surface of different materials including quartz, metal, leather, plastic, and cardboard and the particle size of the water spray did not affect the inactivation effects. This study supplied a disinfection strategy based on plasma-activated air for the inactivation of contaminated pathogenic microorganisms. [Display omitted] • A combined treatment of water spray and plasma-activated air was established for microbial inactivation. • The combined treatment could efficiently inactivate Omicron pseudovirus and bacteria. • The combined treatment induced nitrosative and nitration modification on proteins. • The combined treatment could effectively inactivate microorganisms on the surface of different materials. • The combined treatment provided a new strategy for efficient disinfection of the contaminated microorganisms. [ABSTRACT FROM AUTHOR]