A compact low-temperature plasma jet device was developed to use ambient air as plasma gas. The device was driven by a 2.52-kV high-voltage direct-current pulse in a burst mode, with a repetition rate of 2 kHz. The maximum plasma discharge current was 3.5 A, with an approximately 10 ns full-width half-maximum. Nitric oxide, hydroxyl radical, atomic oxygen, ozone, and hydrogen peroxide—important reactive oxygen and nitrogen species (RONS)—were mainly produced. The amount of plasma-generated RONS can be controlled by varying the pulse-modulation factors. After optimization, the plasma plume length was approximately 5 mm and the treatment temperature was less than 40 °C. The preliminary bactericidal effects were tested on Staphylococcus aureus, Pseudomonas aeruginosa, and methicillin-resistant S. aureus (MRSA), and their biofilms. The results showed that the plasma can effectively inactivate S. aureus, P. aeruginosa, and MRSA in both time- and pulse-dependent manner. Thus, this produced plasma device proved to be an efficient tool for inactivating deteriorating bacteria. Further versatile utilization of this portable plasma generator is also promising.
The wound-healing process can be disrupted at any stage due to various internal and external factors. The inflammatory stage of the process plays a vital role in determining the outcome of the wound. Prolonged inflammation due to bacterial infection can lead to tissue damage, slow healing, and complications. Wound dressings made using materials such as poly (vinyl alcohol) (PVA), chitosan (CS), and poly (ethylene glycol) (PEG) with Mangifera extract (ME) added can help reduce infection and inflammation, creating a conducive environment for faster healing. However, creating the electrospun membrane is challenging due to balancing various forces such as rheological behavior, conductivity, and surface tension. To improve the electrospinnability of the polymer solution, an atmospheric pressure plasma jet can induce chemistry in the solution and increase the polarity of the solvent. Thus, this research aims to investigate the effect of plasma treatment on PVA, CS, and PEG polymer solutions and fabricate ME wound dressing via electrospinning. The results indicated that increasing plasma treatment time increased the viscosity of the polymer solution, from 269 mPa∙to 331 mPa∙s after 60 min, and led to an increase in conductivity from 298 mS/cm to 330 mS/cm and an increase in nanofiber diameter from 90 ± 40 nm to 109 ± 49 nm. Incorporating 1% mangiferin extract into an electrospun nanofiber membrane has been found to increase the inhibition rates of Escherichia coli and Staphylococcus aureus by 29.2% and 61.2%, respectively. Additionally, the fiber diameter decreases when compared with the electrospun nanofiber membrane without ME. Our findings demonstrate that electrospun nanofiber membrane with ME has anti-infective properties and can promote faster wound healing.
The atmospheric pressure plasma technique has been recognized in health care for disinfection in wounds as well as that it can enhance wound healing and reduce pain in patient without side effects. In this study, Dielectric Barrier Discharge Plasma Jets (DBDJs) were used for bactericidal in vitro as well as the efficiency of bacteria killing were investigated using gram positive bacteria, Staphylococcus Aureus (S. Aureus). The DBDJs plasma used He gas at flow rate at 1 L/min, pulse repetition rate between 50 to 110 Hz and exposure time 15 to 60 s for bactericidal. The studies of DBDJs utilized an Optical Emission Spectroscopy (OES) to identify radical species in the plasma. The results of the OES studies showed in DBDJs plasma N2, NO, He and OH radical groups were found. These radicals in plasma played an important role in bactericidal, including wound healing. The intensity of radical in plasma depends on the repetition rate applied by the plasma system. After DBDJs plasma exposure, plates were incubated at 37 °C. Repetition rate and time of plasma exposure were drastically reduced. With the increase in the repetition rate over 100 Hz or exposure time up to 60 s for bactericidal, the reduction of bacteria was increased up to 100 %. The large clear zone showed the efficiency of bacteria killed ability of the plasma.
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