Sang Sik Yang

The therapeutic potential of nonthermal atmospheric-pressure plasma for cancer treatment via generation of reactive species, induction of decreased mitochondrial membrane potential, and sequential apoptosis has been reported in our previous studies. Nonthermal atmospheric-pressure plasma-activated medium produced by jetting air plasma above a liquid surface shows advantages over direct plasma such as storage and delivery to tissues inside the body. In this study, we demonstrated that plasma-activated medium can be stored for up to 6 months in a freezer and that the stored plasma-activated medium has anticancer effects similar to those of direct plasma. Plasma-activated medium stored for 6 months showed cytocidal effects on human cervical cancer HeLa cells that were comparable to the effects of fresh plasma-activated medium or direct plasma. Furthermore, the levels of reactive species in plasma-activated medium persisted for up to 6 months. These results indicate that therapeutic application of plasma-activated medium is applicable in plasma medicine and is a promising anticancer strategy.

An increase in dissolved active species generated and spread using a nonthermal atmospheric plasma device increases water purification and the antimicrobial effect. We propose an underwater plasma device that generates fine bubbles in solution to increase the amount of dissolved active species. Our plasma device has a bubbler with a porosity of 30–50%. Analysis of the inherent active species via an optical emission spectrum, obtained with the developed plasma device shielded from the atmosphere. The underwater plasma from a bubbler with 30–50% porosity is shown to effectively inhibit growth of pathogenic bacteria such as Staphylococcus and Pseudomonas. Reactive oxygen species (ROS) is biological molecules that play an important role in bacterial death. The highest number of ROS is detected in the underwater plasma of the bubbler with 50% porosity. ROS signaling molecules, in particular, singlet oxygen and H₂O₂, could play a role in plasma‐mediated damage to bacteria. The underwater plasma solution of the bubbler with 50% porosity had a strong antimicrobial effect with a considerably low cytotoxic effect on cells, implying that the higher bubbler porosity is more promising for practical use in plasma medicine.

This review gives an overview of the development of surface acoustic wave (SAW) based gyroscopes. Different types of SAW based gyroscope are first presented, which are categorized into standing-wave based or progressive-wave based gyroscopes according to their respective mechanisms. In addition, multi-axis detectable SAW based gyroscopes are also introduced in this review. Different principles, structures, production methods, and control technologies are analyzed.

The plasma jet has been proposed as a novel therapeutic method for anticancer treatment. However, its biological effects and mechanism of action remain elusive. Here, we investigated its cell death effects and underlying molecular mechanisms, using air and N₂ plasma jets from a micro nozzle array. Treatment with air or N₂ plasma jets caused apoptotic death in human cervical cancer HeLa cells, simultaneously with depolarization of mitochondrial membrane potential. In addition, the plasma jets were able to generate reactive oxygen species (ROS), which function as surrogate apoptotic signals by targeting the mitochondrial membrane potential. Antioxidants or caspase inhibitors ameliorated the apoptotic cell death induced by the air and N₂ plasma jets, suggesting that the plasma jet may generate ROS as a proapoptotic cue, thus initiating mitochondria-mediated apoptosis. Taken together, our data suggest the potential employment of plasma jets as a novel therapy for cancer.