Recently, much attention has been paid to the use of low-temperature plasmas and plasma-activated water (PAW) in various areas of biological research. In addition to its use in medicine, especially for low-temperature disinfection and sterilization, a number of works using plasma in various fields of agriculture have already appeared. While direct plasma action involves the effects of many highly reactive species with short lifetimes, the use of PAW involves the action of only long-lived particles. A number of articles have shown that the main stable components of PAW are H2O2, O3, HNO2, and HNO3. If so, then it would be faster and much more practical to artificially prepare PAW by directly mixing these chemicals in a given ratio. In this article, we review the literature describing the composition and properties of PAW prepared by various methods. We also draw attention to an otherwise rather neglected fact, that there are no significant differences between the action of PAW and artificially prepared PAW. The effect of PAW on the properties of wheat grains (Triticum aestivum L.) was determined. PAW exposure increased germination, shoot length, and fresh and dry shoot weight. The root length and R/S length, i.e., the ratio between the underground (R) and aboveground (S) length of the wheat seedlings, slightly decreased, while the other parameters changed only irregularly or not at all. Grains artificially inoculated with Escherichia coli were significantly decontaminated after only one hour of exposure to PAW, while Saccharomyces cerevisiae decontamination required soaking for 24 h. The differences between the PAW prepared by plasma treatment and the PAW prepared by artificially mixing the active ingredients, i.e., nitric acid and hydrogen peroxide, proved to be inconsistent and statistically insignificant. Therefore, it may be sufficient for further research to focus only on the effects of artificial PAW.

• Keywords
• nonthermal plasma, plasma-activated water, seed treatment,
• Publication type
• Journal Article MeSH

Water suspensions of cysts of a pathogenic clinical isolate of Acanthamoeba sp. were prepared, and the cysts were inactivated either in suspension or placed on the surface of contact lenses by the non-thermal plasma produced by the DC corona transient spark discharge. The efficacy of this treatment was determined by cultivation and the presence of vegetative trophozoites indicating non-inactivated cysts. The negative discharge appeared to be more effective than the positive one. The complete inactivation occurred in water suspension after 40 min and on contaminated lenses after 50 min of plasma exposure. The properties of lenses seem to not be affected by plasma exposure; that is, their optical power, diameter, curvature, water content and infrared and Raman spectra remain unchanged.

• Keywords
• Acanthamoeba, DC corona discharge, IR spectra, Raman spectra, contact lenses, cysts,
• Publication type
• Journal Article MeSH

In recent decades, the non-thermal plasma, i.e. partially or completely ionized gas produced by electric discharges at ambient temperature, has become of interest for its microbiocidal properties with potential of use in the food industry or medicine. Recently, this interest focuses not only on the planktonic forms of microorganisms but also on their biofilms. The works in this interdisciplinary field are summarized in this review. The wide range of biofilm-plasma interactions is divided into studies of general plasma action on bacteria, on biofilm and on its oral and dental application; a short overview of plasma instrumentation is also included. In addition, not only biofilm combating but also an important area of biofilm prevention is discussed. Various DC discharges of the point-to-plane type. Author's photograph, published in Khun et al. (Plasma Sources Sci Technol 27:065002, 2018).

• Keywords
• Biofilm inactivation, Biofilm prevention, Dental and oral, Non-thermal plasma production, Wound healing,
• MeSH
• Bacteria growth & development   radiation effects   MeSH
• Biofilms growth & development   radiation effects   MeSH
• Disinfection instrumentation   methods   MeSH
• Wound Healing MeSH
• Fungi radiation effects   MeSH
• Plasma Gases pharmacology   MeSH
• Food Industry MeSH
• Dental Materials pharmacology   MeSH
• Publication type
• Journal Article MeSH
• Review MeSH
• Names of Substances
• Plasma Gases MeSH
• Dental Materials MeSH

Non-thermal plasma has proved its benefits in medicine, plasma assisted polymerization, food industry and many other fields. Even though, the ability of non-thermal plasma to modify surface properties of various materials is generally known, only limited attention has been given to exploitations of this treatment on conductive polymers. Here, we show study of non-thermal plasma treatment on properties of globular and nanostructured polypyrrole in the distilled water. We observe that plasma presence over the suspension level doesn't change morphology of the polymer (shape), but significantly influences its elemental composition and physical properties. After 60 min of treatment, the relative concentration of chloride counter ions decreased approximately 3 and 4 times for nanostructured and globular form, respectively and concentration of oxygen increased approximately 3 times for both forms. Simultaneously, conductivity decrease (14 times for globular and 2 times for nanostructured one) and changes in zeta potential characteristics of both samples were observed. The modification evolution was dominated by multi-exponential function with time constants having values approximately 1 and 10 min for both samples. It is expected that these time constants are related to two modification processes connected to direct presence of the spark and to long-lived species generated by the plasma.

• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH