Comparison of non-thermal plasma generating devices suitable for bioapplications*

Thanks to the great expansion of bioapplications of non-thermal plasma (NTP), there exist many scientific groups in this field of research using various types of NTP generating devices. However, the results presented in numerous studies are basically impossible to compared between each other due to the variation in species of microorganisms, sample preparations, treatment conditions, etc. Thus, in this work the comparison of 7 different NTP generating devices regarding their technical parameters and sporocidal properties was made. For this purpose the robust and reproducible standard protocol was used to prepare and process the samples. Inhibition zones on a sample as well as the overall inhibition of viable spores numbers after the NTP treatment were examined. Furthermore, the technical specifications of different NTP generating devices and temperature maps of NTP exposed membranes were compared. This information should characterize the NTP generating device well enough to allow a good estimate of its potential bioapplication. In addition, based on the obtained results, some general trends regarding the parameters influencing the resulting antimicrobial effect were revealed. This extensive comparison study is unique in many aspects since the cooperation of 5 institutions and 8 researchers was needed to realize it and all the devices included are very varied in all aspects: appearance and use, technical parameters, intended application and effectiveness against the B. subtilis spores.