Aqueous reactive species induced by a PCB surface micro-discharge air plasma device: a quantitative study

This paper presents a quantitative investigation on aqueous reactive species induced by air plasma generated from a printed circuit board surface micro-discharge (SMD) device. Under the conditions amenable for proliferation of mammalian cells, concentrations of ten types of reactive oxygen and nitrogen species (RONS) in phosphate buffering solution (PBS) are measured by chemical fluorescent assays and electron spin resonance spectroscopy (ESR). Results show that concentrations of several detected RNS (NO^-₂ , NO^-₃ , peroxynitrites, and NO^-₂) are higher than those of ROS (H₂O₂, O^-₂, and ¹O₂) in the air plasma treated solution. Concentrations of NO^-₃ can reach 150 times of H2O2 with 60 s plasma treatment. For shortlived species, the air plasma generates more copious peroxynitrite than other RONS including NO^-₂, O^-₂ , ¹O₂, and NO in PBS. In addition, the existence of reaction between H₂O₂ and NO^-₂/HNO₂ to produce peroxynitrite is verified by the chemical scavenger experiments. The reaction relations between detected RONS are also discussed.