Upgrading the production of plasma-activated water for sterilization by preloading long-lived reactive species

Plasma-activated water (PAW) has broad prospects in the medical field because it is rich in reactive nitrogen and oxygen species. However, in most production processes of PAW, a large proportion of gaseous reactive species is converted into long-lived aqueous species with minor biochemical activity, and only a small proportion is converted into crucial short-lived aqueous species, which results in inefficient activation of PAW. Given the indispensability and easy availability of long-lived aqueous species, this study proposes to preload HNO₃ and H₂O₂ into water and then generate plasma to induce short-lived aqueous species, thus improving the production rate of PAW. The addition of 1 mM HNO₃ and 0.5% H₂O₂ results in a 100-fold increase in the production rate of the PAW with a bactericidal rate exceeding 99.9999%, and the preloaded HNO₃ and H₂O₂ promote the dissolution of O₃ and the generation of short-lived aqueous species, respectively. Moreover, the preloaded species improve the validity period of PAW and the resistance of sterilization to acid-base neutralizers. This study offers a novel approach for upgrading the production of PAW, which holds promise for realizing rapid PAW production with a portable device for clinical medical applications.