Influence of Controlling Plasma Gas Species and Temperature on Reactive Species and Bactericidal Effect of the Plasma

In this study, plasma gas species and temperature were varied to evaluate the reactive species produced and the bactericidal effect of plasma. Nitrogen, carbon dioxide, oxygen, and argon were used as the gas species, and the gas temperature of each plasma was varied from 30 to 90 °C. Singlet oxygen, OH radicals, hydrogen peroxide, and ozone generated by the plasma were trapped in a liquid, and then measured. Nitrogen plasma produced up to 172 µM of the OH radical, which was higher than that of the other plasmas. In carbon dioxide plasma, the concentration of singlet oxygen increased from 77 to 812 µM, as the plasma gas temperature increased from 30 to 90 °C. The bactericidal effect of carbon dioxide and nitrogen plasma was evaluated using bactericidal ability, which indicated the log reduction per minute. In carbon dioxide plasma, the bactericidal ability increased from 5.6 to 38.8, as the temperature of the plasma gas increased from 30 to 90 °C. Conversely, nitrogen plasma did not exhibit a high bactericidal effect. These results demonstrate that the plasma gas type and temperature have a significant influence on the reactive species produced and the bactericidal effect of plasma.

Improve the Electrical Properties of the ITO-PET Polymer by Plasma Technique

At present the applications of the conductive polymer are monitor, batteries and the sensors but there have been limitations due to the manufacturing costs, material inconsistencies, toxicity, poor solubility in solvents, and inability to directly melt process. Regarding these problems, in this research to studies the condition to enhance the conductive polymer were conducted via the carbon dioxide plasma technique coated on ITO-PET. The plasma power is 50, 75, 100, 125 and 150 watts in the vacuum conditions for periods 10, 20 and 30 mins respectively. The electrical properties were measured via the 4 point probe. The contact angle for analyzing the hydrophobic was analyzed. The result demonstrated that the power of the plasma and the time has influence on the conductive polymer. With the time for doping at 20 mins the current increased compare to the control item. However, with the time doping at 10 and 30 mins the current decreased. The maximum current at 10 mins doping is 22 mA at the 7 volts in the conduction of 75 watts plasma power. The contact angle of the ITO-PET polymer decrease from 110 degree to 44-95 degree. Henceforth when using the carbon dioxide plasma the phenomenal of hydrophilic increases.

Antimicrobial nature and healing behavior of plasma functionalized polyester sutures

This study deals with the development of bioactive poly(ethylene terephthalate) surgical suture by adopting the immobilization route with bioactive nanogels and chlorhexidine. Carbon dioxide plasma was used for the generation of carboxyl functionality on poly(ethylene terephthalate) surface for the immobilization of the bioactive components. The nanosilver nanogel was prepared using polyethylene glycol which helps in the reduction of silver ions into nanosilver as well as the stabilization of nanoparticles. The particle size of the nanogels, as evaluated by high-resolution transmission electron microscopy, was observed to be in the range of 10–50 nm. Surface functionalization of poly(ethylene terephthalate) filament was observed by attenuated total reflectance measurements and mechanical studies were investigated by Instron. Elemental analysis and surface topography were carried out by energy dispersive X-ray and atomic force microscopy. The cumulative release of silver from the dressing was found to be 68% of the total loading after 72 h. Coated sutures have excellent antimicrobial activity against both Escherichia coli and Staphylococcus aureus. In vivo wound healing and histopathology studies were carried out over a period of 72 h for skin wounds created on Swiss albino mice. Fast healing was observed in nanogel-treated wounds without any inflammatory effects on the newly generated skin. These sutures offer improved healing along with excellent antimicrobial properties and appear to be promising material against surgical infection.

Hydrogen Production by Hydrolysis of NaBH4 with Cr-Ni-W-B Catalyst: Effects of Cold Plasma and Chromium Content

In this study, the hydrogen generation from the hydrolysis of NaBH4 with Cr0.0125-Ni-W-B catalyst prepared in the presence of cold plasma was investigated based on Cr content, NaBH4 concentration, NaOH concentration, temperature, plasma applying time and plasma gases effects. The results of the activity tests indicate that the choice of Cr and the catalyst composition greatly influenced the activity as well as the selectivity for hydrogen generation from the hydrolysis of NaBH4. The Cr0.0125-Ni-W-B catalyst was treated with argon, nitrogen and carbon dioxide plasma at different treatment times. The catalysts were characterized using SEM, BET surface area measurement and XRD.