Properties Of Plasma-activated Water Research Articles

Plasma-activated water regulated transcriptome gene expression leading to high germination and growth of mung beans

BackgroundPlasma-activated water (PAW) is a solution created by exposing water to cold atmospheric plasma discharge, resulting in a biocidal agent with unique biochemical properties attributed to highly reactive oxygen and nitrogen species (RONS). Plasma-activated water (PAW) has been the subject of research for its potential in promoting seed germination. While it has shown promising results, the exact mechanism by which PAW promotes seed growth remains unclear. This study aims to investigate the role of PAW in promoting mung bean germination, including its effects on vitality improvement and the triggering of plant stress responses to promote crop growth. Through the utilization of next-generation sequencing, we aim to explore the interaction between the properties of PAW and gene expression in mung beans. By deciphering the nature of PAW and analyzing gene expression patterns, we hope to uncover the underlying mechanisms that govern their interaction.ResultsThe results revealed that nitrogen plasma-activated water (NPAW) treatment improves the vitality and hypocotyl length of mung beans and leads to a good overall growth state. Moreover, we identified numerous differentially expressed genes (DEGs), including genes related to stress responses, growth regulation, and metabolic processes, that were upregulated or downregulated in response to PAW treatment. As a result of APAW treatment, 168 genes were upregulated and 90 genes were downregulated. Furthermore, 179 genes were upregulated in the NPAW compared to 125 genes that were downregulated in the control group. Gene expression analysis revealed involvement in stress signaling and metabolic processes.ConclusionsPAW treatment can promote crop growth and serve as a reference for other seeds. This research provides insights into the regulatory mechanisms and benefits of PAW in sustainable agriculture.Graphical

Selective generation of reactive oxygen species in plasma-activated water using CO2 plasma

In this study, we discuss a process for selectively generating reactive oxygen species (ROS), such as H2O2 and dissolved O3, in plasma-activated water (PAW) using pure CO2 as a plasma-forming gas. A detailed comparison of the gas species/radicals present in plasma and the properties of PAW when using CO2 and air as plasma-forming gases is presented. Our results show that PAW generated with CO2 has a significantly higher pH and lower oxidizing potential and electrical conductivity compared to PAW generated with air. Species formed in PAW (CO2) due to CO2 plasma-water interaction include dissolved O3, H2O2, dissolved CO2, CO32− ions, etc. Moreover, the concentration of NO2− and NO3− ions in PAW (CO2) is beyond the detection limit. PAW (CO2) has a substantially higher concentration of H2O2 than PAW (air). Furthermore, increasing the plasma treatment time with water significantly increases the concentration of H2O2 and dissolved O3 in PAW (CO2). In conclusion, our study demonstrates that selective generation of ROS in PAW is possible using CO2 as a plasma-forming gas, leading to a higher H2O2 concentration compared to air.

The role of different plasma forming gases on chemical species formed in plasma activated water (PAW) and their effect on its properties

The present work showed the role of plasma-forming gases (air, nitrogen (N2), argon (Ar), helium (He), and their mixture with oxygen (O2)) on the properties of plasma-activated water (PAW). Electrical diagnosis and optical emission spectroscopy were performed to characterize plasma and identify plasma radicals/species. The PAW is characterized by studying its physicochemical properties and dissolved reactive oxygen-nitrogen species (RONS) concentration in it. The results showed introducing O2 in N2, Ar and He plasma suppresses the emission lines intensity of NOϒ band in N2 plasma, OH band in Ar and He plasma, and N2 second positive system in He plasma. Also, adding O2 to Ar and He plasma changes the plasma discharge characteristic from glow discharge to filamentary micro-discharge. The PAW prepared by air and its mixture with O2 showed improved physicochemical properties and RONS concentration in it compared to other plasma forming gases and their mixture with O2. In addition, increasing plasma-water exposure time significantly affects the physicochemical properties and RONS concentration in PAW. Therefore, plasma forming gas and plasma-water exposure time gives better control over the properties of PAW. Hence, these parameters play a significant role in deciding the applications of PAW.

A comparative study of dielectric barrier discharge plasma device and plasma jet to generate plasma activated water and post-discharge trapping of reactive species

This work shows a comparative study of a change in properties of plasma-activated water (PAW) when prepared by using two different dielectric barrier discharge (DBD) configurations named a pencil plasma jet (PPJ) and a plasma device (PD). The air plasma produced from the DBD-PPJ and DBD-PD is characterized by voltage-current characteristics, and plasma species/radicals are identified using optical emission spectroscopy. Moreover, the present work emphasizes the trapping of reactive species (O3, NOx, etc.) carried by post-discharge residual gases during PAW production. The trapping of these gases' reactive species is carried out in water, which provides a useful by-product named plasma processed water (PPW). The results revealed a higher concentration of reactive oxygen species (dissolved O3 and H2O2) and a lower concentration of reactive nitrogen species (NO3− and NO2− ions) in PAW prepared by the DBD-PPJ configuration compared to the DBD-PD configuration. The trapping of reactive species (O3 and NOx) present in post-discharge residual gases is confirmed by determining the change in physicochemical properties and reactive oxygen–nitrogen species (RONS) concentration in virgin water used as a trapping medium. The high concentration of RONS in PPW showed a high concentration of reactive species in post-discharge residual gases and vice versa. Therefore, the reduction in reactive species downstream of post-discharge residual gases is shown by a substantial decrease in the concentration of RONS and physicochemical properties of PPW. Thus, PAW and PPW (by-product) prepared in this work could be used for multiple applications such as microbial inactivation, food preservation, and agriculture.

Properties of plasma-activated water with different activation time and its effects on the quality of button mushrooms (Agaricus bisporus)

This study aimed to develop an underwater air plasma generator to produce plasma-activated water (PAW). The effect of plasma activation time on the physicochemical properties of PAW and the effect of thus-generated PAW on the postharvest quality of button mushrooms were investigated. The results showed that the pH value, electrical conductivity, and oxidation-reduction potential of PAW were significantly dependent on plasma activation time, while no obvious changes were observed in PAW temperature during the whole activation process. The PAW treatment effectively inactivated Escherichia coli cells on the surface of button mushrooms, with the bacterial reduction from 0.11 to 1.32 log10 CFU/g when the activation time increased from 5 to 25 min. Furthermore, PAW treatment delayed the browning process, extended the shelf life of mushrooms, and affected other quality attributes of mushrooms. Among all these groups with PAW treatment, the 20-PAW-treated groups showed the highest firmness and total soluble solid content, and the lowest browning index and relative electrical conductivity during the whole storage duration. Additionally, no significant changes were observed in the pH and 1,1-dipheny1-2-picrylhydrazyl radical-scavenging capacity among all groups.