Experimental study of disinfection effect of a new low-temperature plasma disinfector / 西安交通大学学报(医学版)

【Objective】 To observe the inactivation effect of a new low-temperature plasma air disinfector on microorganisms in the natural environment and artificial contaminated environment so as to further determine the minimum effective processing parameters. 【Methods】 First， in 0.5 m3 of super clean workbench and 1.05 m3 airtight organic glass cavity in the body， the new low-temperature plasma air disinfector developed was used to inactivate the natural bacteria in the air under different parameters. Then in 1.05 m3 airtight organic glass cavity in the body， the new low-temperature plasma air disinfector was used to treat the Staphylococcus aureus and Escherichia coli under the condition of artificial bacteria spraying. Last， the plate counting method was used to evaluate the inactivation effect of the disinfector on natural bacteria and artificial bacteria in the air. 【Results】 For the low-temperature plasma air disinfector in 0.5 m3 and 1.05 m3 confined space， the lowest effective treatment parameters for inactivated natural bacteria were 13 kV， 5 min or 12 kV， 10 min. For the low-temperature plasma air disinfection machine in 13 kV discharge voltage treatment of different time， compared with before treatment， the killing rate of Escherichia coli and Staphylococcus aureus increased significantly after treatment for 20 min （P<0.000 1）. Both could meet the requirements of disinfection specifications ［100%， （99.98±0.01）%≥99.90%］. 【Conclusion】 The inactivation of natural bacteria and artificial bacteria by the new low-temperature plasma air disinfector has reached the qualified standard of disinfection stipulated in Technical Specifications for Disinfection.

Effect of low-temperature plasma on wound healing of mouse skin / 西安交通大学学报(医学版)

Objective To compare the different doses of low-temperature plasma (LTP) on wound healing in BALB/c mice so as to discuss the effects of the optimal dose of low-temperature plasma dealing with wound in mice and the acting mechanism of wound healing.Methods Adoptatmospheric pressure plasma jet discharged by the dielectric barrier was used to treat mouse skin wound.According to the processing time, the wounds were divided into 10s, 20s, 30s, 40s and 50s experimental groups, while naturally healing wounds served as negative controls and the wounds dealt with recombinant human epidermal growth factor served as positive controls.We recorded the wound size every day, observed the histopathological changes, the expression level of type Ⅰ collagen by immunofluorescence, and analyzed the composition of low-temperature plasma jet.Results The wounds with plasma treatment time of 10s, 20s, 30s, and 40s showed significant daily improvement and almost complete closure at days 12, 10, 7, 13, respectively.However, the wounds with plasma treatment time of 50s remained unhealed atday 14.The wounds in positive control group all healed, and the wound healing effect in positive control group could be achieved in 30s group.HE staining and immunofluorescence staining assays showed the optimal result of epidermal cell regeneration, granulation tissue hyperplasia, and collagen deposition in histological aspect at day 7 in 30 s group.The low-temperature plasma jet contained highly reactive free radicals of nitrogen and oxygen, which play an important role in wound healing process.Conclusion Appropriate doses of cold plasma can accelerate wound healing whereas over-doses of plasma can suppress wound healing.The process of wound healing may be related to reactive oxygen and nitrogen species in LTP.