Nitrogen fixation is crucial for plants as it is utilized for the biosynthesis of almost all biomolecules. Most of our atmosphere consists of nitrogen, but plants cannot straightforwardly assimilate this from the air, and natural nitrogen fixation is inadequate to meet the extreme necessities of global nutrition. In this study, nitrogen fixation in water was achieved by an AC-driven non-thermal atmospheric pressure nitrogen plasma jet. In addition, Mg, Al, or Zn was immersed in the water, which neutralized the plasma-treated water and increased the rate of nitrogen reduction to ammonia due to the additional hydrogen generated by the reaction between the plasma-generated acid and metal. The effect of the plasma-activated water, with and without metal ions, on germination and growth in corn plants (Zea Mays) was investigated. The germination rate was found to be higher with plasma-treated water and more efficient in the presence of metal ions. Stem lengths and germination rates were significantly increased with respect to those produced by DI water irrigation. The plants responded to the abundance of nitrogen by producing intensely green leaves because of their increased chlorophyll and protein contents. Based on this report, non-thermal plasma reactors could be used to substantially enhance seed germination and seedling growth.

Cold atmospheric pressure plasma jets (plasma) operated in ambient air provide a rich source of reactive oxygen and nitrogen species (RONS), which are known to influence biological processes important in disease. In the plasma treatment of diseased tissue such as subcutaneous cancer tumors, plasma RONS need to first traverse an interface between the plasma-skin surface and second be transported to millimeter depths in order to reach deep-seated diseased cells. However, the mechanisms in the plasma generation of RONS within soft tissues are not understood. In this study, we track the plasma jet delivery of RONS into a tissue model target and we delineate two processes: through target delivery of RONS generated (primarily) in the plasma jet and in situ RONS generation by UV photolysis within the target. We demonstrate that UV photolysis promotes the rapid generation of RONS in the tissue model target's surface after which the RONS are transported to millimeter depths via a slower molecular process. Our results imply that the flux of UV photons from plasma jets is important for delivering RONS through seemingly impenetrable barriers such as skin. The findings have implications not only in treatments of living tissues but also in the functionalization of soft hydrated biomaterials such as hydrogels and extracellular matrix derived tissue scaffolds.

We investigated the characteristics of a rollable dielectric barrier discharge (RDBD) and evaluate its effects on seed germination rate and water uptake. The RDBD source was composed of a polyimide substrate and copper electrode, and it was mounted in a rolled-up structure for omnidirectional and uniform treatment of seeds with flowing synthetic air gas. The rotational and vibrational temperatures were measured to be 342 K and 2860 K, respectively, using optical emission spectroscopy. The chemical species analysis via Fourier-transform infrared spectroscopy and 0D chemical simulation showed that O₃ production was dominant and NO_x production was restrained at the given temperatures. The water uptake and germination rate of spinach seeds by 5 min treatment of RDBD was increased by 10% and 15%, respectively, and the standard error of germination was reduced by 4% in comparison with the controls. RDBD enables an important step forward in non-thermal atmospheric-pressure plasma agriculture for omnidirectional seed treatment.

Glioblastoma multiforme (GBM) is a highly malignant and rapidly advancing astrocytic brain tumor in adults. Current therapy possibilities are chemotherapy, surgical resection, and radiation. The complexity of drug release through the blood-brain barrier, tumor reaction to chemotherapy, and the inherent resistance of tumor cells present challenges. New therapies are needed for individual use or combination with conventional methods for more effective treatment and improved survival for patients. GBM is difficult to treat because it grows quickly, spreads finger-shaped tentacles, and creates an irregular margin of normal tissue surrounding the tumor. Non-thermal biocompatible plasma (NBP) has recently been shown to selectively target cancer cells with minimal effects on regular cells, acting by generating reactive oxygen species (ROS) and reactive nitrogen species (RNS). We applied a soft jet plasma device with a syringe shape to U87 MG cells and astrocytes. Our results show that NBP-J significantly inhibits cell proliferation and changes morphology, induces cell cycle arrest, inhibits the survival pathway, and induces apoptosis. Our results indicate that NBP-J may be an efficient and safe clinical device for brain cancer therapy.

Optimizing the therapeutic range of nonthermal atmospheric pressure plasma (NTAPP) for biomedical applications is an active research topic. For the first time, we examined the effect of plasma on-times in this study while keeping the duty ratio and treatment time fixed. We have evaluated the electrical, optical, and soft jet properties for two different duty ratios of 10% and 36%, using the plasma on-times of 25, 50, 75, and 100 ms. Furthermore, the influence of plasma on-time on reactive oxygen and nitrogen species (ROS/RNS) levels in plasma treated medium (PTM) was also investigated. Following treatment, the characteristics of (DMEM media) and PTM (pH, EC, and ORP) were also examined. While EC and ORP rose by raising plasma on-time, pH remained unchanged. Finally, the PTM was used to observe the cell viability and ATP levels in U87-MG brain cancer cells. We found it interesting that, by increasing the plasma on-time, the levels of ROS/RNS dramatically increased in PTM and significantly affected the viability and ATP levels of the U87-MG cell line. The results of this study provide a significant indication of advancement by introducing the optimization of plasma on-time to increase the efficacy of the soft plasma jet for biomedical applications.