Traces of isotopic reactive species produced from a non-thermal plasma jet in bio-molecules

Abstract

Heavy water (D _2 O) is introduced into a non-thermal plasma jet (NTPJ) device to generate deuterium monoxide (OD) radicals instead of hydroxyl (OH) radicals. An NTPJ generated from a vapor mixture of N _2 /H _2 O and N _2 /D _2 O is applied to a cell membrane component and its effects are analyzed by means of ^1 H NMR, GC-FID and TOF-SIMS spectroscopies. The results show that OH and OD radical species induce similar levels of oxidative breakage of lipid molecules. In addition, the ^2 H NMR spectra show that deuteriums are incorporated into the lipid oxidative products. In order to trace these effects in vivo , E. coli bacteria are treated with an NTPJ and analyzed using NanoSIMS. Deuterium is observed in both the cytoplasm and membrane, which are colocalized well with nitrogen and phosphorus atoms. The high colocalization of D atoms inside E. coli provides the first direct and visual evidence of the role of OD radicals, which may be utilized to visualize OH radical interactions inside cells.

Keywords

• heavy water
• OH radical
• fatty acid
• non thermal plasma jet
• E. coli
• NanoSIMS