Increasing emergence of antibiotic resistance in bacteria during the past few decades has become a major public health concern and has reduced the efficacy of conventional therapies. The objective of the current study is to examine the bactericidal efficacy of atmospheric pressure nonthermal dielectric barrier discharge (DBD) plasma on methicillin-resistant Staphylococcus aureus (MRSA) as a common musculoskeletal pathogen and Escherichia coli (E. coli) as another cause of bone, joint, and soft tissue infections in planktonic phase and in colonies. In planktonic phase, results demonstrated complete decontamination of E. coli and MRSA cells on agar plates with a bacterial surface density of 1.27 10 5 colony-forming units (CFU)/ cm 2 following 30 seconds and 60 seconds of plasma treatment, respectively. Reduction rates of 7 log10 steps in the number of viable CFUs in E. coli colonies was observed following 5 minutes of plasma treatment. The colony growth was halted, and no more growth in colony size was observed during a 24-hour monitoring period. For MRSA colonies, results demonstrated 2 log10 to 7 log10 steps reduction in the number of viable CFUs in each colony after 5 minutes of plasma treatment. Results indicated that plasma-treated colonies will have prolonged lag time during generation of the growth curves. Finally, diffusion of nitric oxide into the agarose gel was confirmed as a reactive agent that was effective in the decontamination process.

aureus (grampositive), and Candida albicans(yeast).

The reactive flow field and the mechanism of sterilization by steam plasma flow at atmospheric pressure were clarified to develop a new sterilization system by experimental and computational methods. The emission lines of OH, whose intensity increased with increased applied voltage and frequency, were observed in the discharge region. The OH radical finally changed to H 2 O 2 in the condensed water. The OH radical was capable of sterilizing spores of Geobacillus stearothermophilus, although the condensed water did not have such effect. The discharge process was clarified with an axisymmetric, non-Maxwellian model. The OH radical was generated by a wire electrode toward the ground electrode, and the concentration of H 2 O 2 increased after streamer propagation.

Low energy ionized gas coagulation equipment (LE-IGCE) using low temperature nonthermal atmospheric pressure plasmas has been attracting special attention with the popularization of minimally invasive surgery. In this work, the thermal characteristics of a commercial high energy ionized gas coagulation equipment (HE-IGCE) and a specially designed LE-IGCE have been studied using an infrared camera and optical emission spectroscopy during their treatments. The four substrates used for the treatments were pork meats, copper (Cu) plates, wet tissues, and glass plates. In the HE-IGCE treatment, the surface temperature of the pork meat rose to 350°C, and the rotational temperatures of nitrogen molecules in plasmas were 450 to 1630 K, depending on which substrate was used during HE-IGCE treatments. In the LE-IGCE treatment, the surface temperature of pork meats was lower than 40°C, and the rotational temperatures of nitrogen molecules were lower than 350 K. The results show that the LE-IGCE can maintain the temperature of biological tissue below the threshold that would cause irreversible tissue damage.

This study evaluated the antifungal potential of low-temperature plasma (LTP) on a 72-hour Candida albicans biofilm. A growth inhibition zone test was conducted with agar plates inoculated with C. albicans and submitted to LTP and argon application at 3 and 10 mm for 10, 30, 60, 90, and 120 seconds. The groups for biofilm assays were 60 seconds of LTP application with a tip-to-sample distance of 3 mm (LTP-3) and 10 mm (LTP-10); -application of only argon gas for 60 seconds with a tip-to-sample distance of 3 mm (Ar-3) and 10 mm (Ar-10); and no treat- ment. The C. albicans biofilm was grown on saliva-coated discs. The medium was replaced every 24 hours. Confocal laser scanning microscopy revealed the proportion of live and dead cells, and variable pressure scanning electron microscopy (VPSEM) showed biofilm/cell structure. No in - hibition zone was observed for control and either Ar groups. For the LTP groups, a progressively increasing of inhibition zone diameter was observed for different treatment durations. The LTP-3 and LTP-10 groups presented higher proportions of dead cells compared with the Ar-3 and Ar-10 groups. VPSEM revealed cell perforations in the LTP-3 and LTP-10 groups. A short period of LTP exposure demonstrated an antifungal effect on C. albicans biofilm.

Plasma methods are widely applied today in different aspects of tissue engineering. The chapter first considers plasma control of the biological properties of medical polymers and biocompatibility. Plasma treatment cleans the polymer surface and makes it highly hydrophilic. This results in the enhancement of adhesion properties of the polymer materials. Fracture repair is a dynamic process requiring the mobilization and activation of stem cells to achieve new bone formation and increase resorption of old bone. The application of non-thermal plasma in this regard provides new methods to exploit these phenomena to advance the rapidly growing field of regenerative medicine. Plasma treatment of polymers usually results in the production of gases with a flow rate close to that of the initial plasma gas. The polymer is therefore treated in plasma, which not only includes the initial plasma gas, but also the gas generated during the treatment process.

Plasma medicine is a multidisciplinary branch of modern science and technology. This introductory chapter of Introduction to Fundamental and Applied Aspects of Plasma Medicine presents some initial thoughts on the motivating results of the application of plasma medicine. It provides an overview of the book, which focuses on the fundamental and practical aspects of plasma applications to medicine, biology, and related disciplines. Very important concepts group plasma physics, plasma chemistry, and plasma medicine into two major classes — those of thermal and non-thermal plasmas. This chapter also talks about plasma as a non-equilibrium multi-temperature system, natural and man-made, completely and weakly ionized plasmas, as a non-equilibrium multi-temperature system, and gas discharges as plasma sources for biology and medicine. It provides insights into plasma chemistry as the fundamental basis of plasma medicine, non-thermal plasma interaction with cells and living tissues, and applied plasma medicine.

Cold atmospheric pressure plasmas (CAPs) are being investigated for medical applications, and the first clinical studies are promising. However, interactions between plas- mas and biological samples are only partly understood on a molecular level. In this study, bo- vine serum albumin (BSA), a standard model for plasma-mediated etching of biological sam- ples, was used to investigate the effects of different components of an He/O 2 plasma effluent on proteins. The X-jet features an optional lateral helium flow that splits the plasma effluent into particles and (V)UV radiation. BSA samples were exposed separately to plasma-emitted particles, UV radiation, or the combination of both. Afterward, plasma-treated samples were investigated using SDS-PAGE and western blot analysis for amino acid strand breaks, but none were detected. Furthermore, treated samples were investigated by Raman spectroscopy to search for chemical modifications. We found that treatment with the X-jet has little effect on BSA. Minor changes in the Raman spectra suggest modifications of tyrosine residues and some degree of oxidation of sulfur-containing amino acids. Our findings suggest that for the X-jet effluent, etching is the main effect of plasma on BSA, making BSA a suitable model with which to study protein etching.