Nonthermal Atmospheric Plasma-Induced Cellular Envelope Damage of Staphylococcus aureus and Candida albicans Biofilms: Spectroscopic and Biochemical Investigations

Objective: Nonthermal plasma at atmospheric condition using dielectric barrier discharge (DBD) is reported to be useful in many applications. Here, we have developed a strategy to generate nonthermal atmospheric plasma (NTAP) at ambient conditions for potential biomedical applications. Methods: We have explored the active ingredients of the nonthermal plasma using atomic emission spectroscopy. The potential mechanism of the generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) from the generated plasma for therapeutic use has been demonstrated. Major results: The antimicrobial efficacy of the nonthermal plasma application to model Staphylococcus aureus and Candida albicans biofilms has been investigated. Our detailed electron microscopic studies followed by biochemical investigation reveal the mechanism of bacterial/fungal deactivation process. The nuclear magnetic resonance (NMR) studies on the live cell of C . albicans before and after NTAP treatment clearly conclude the disruption of cellular envelope leading to necrosis as evidenced by fluorescence-assisted cell sorting (FACS) studies. Conclusions: The proposed NTAP setup may find relevance in novel strategies in bacterial and fungal biofilm destruction in the future development of nonfluid hand sanitization.