Non-thermal oxygen-rich helium plasmas using theta shaped tubing for evaluation of plasmid DNA strand breaks

Summary form only given. While atmospheric pressure plasmas based on mixtures of helium and oxygen have been used for biomedical applications benefiting from reactive oxygen species (ROS)^1,2, the large electron affinity and heavy mass/large size of the oxygen ions precludes stable plasma discharge at low voltage driving conditions. Here, non-thermal oxygen-rich helium plasmas were investigated to achieve enhanced reactive oxygen species concentration without deficiencies in driving conditions. A theta-shaped tube-based atmospheric pressure oxygen-rich helium plasma device has been fabricated and its potential has been investigated for use in topological alteration of plasmid DNA. The optical emission spectra of the plasma from the device showed even if an oxygen plasma is not produced directly, the oxygen flow clearly participates in the plasma process and affects the plasma properties. The oxygen-rich helium plasma generated by our proposed plasma jet device was observed to induce the strand breaks of plasmid DNA in a plasma dose-dependent manner. Further, the effect of the plasma treatments on DNA was enhanced with an increase of oxygen gas concentration while other parameters were held constant. Based on optical emission spectra (OES) and DNA analysis, the atmospheric pressure helium plasmas with oxygen-rich atmosphere increased the ROS in the plasma medium and resulted in a significant enhancement of DNA strand breaks than when only a helium plasma was used. This ROS controllable non-thermal helium plasma device driven at low operating voltage provides a method for sterilizations/decontaminations, plasma cancer therapy, tooth bleaching, wound healings, skin regenerations, as well as providing further insight into apoptosis mechanisms in biomedical applications.