Application of Ultraviolet-C Radiation and Gaseous Ozone for Microbial Inactivation on Different Materials

Abstract

With the advent of the COVID-19 pandemic, there has been a global incentive for applying environmentally sustainable and rapid sterilization methods, such as ultraviolet-C radiation (UVC) and ozonation. Material sterilization is a requirement for a variety of industries, including food, water treatment, clothing, healthcare, medical equipment, and pharmaceuticals. It becomes inevitable when devices and items like protective equipment are to be reused on/by different persons. This study presents novel findings on the performance of these sterilization methods using four microorganisms (Escherichia coli , Staphylococcus aureus , Candida albicans , and Aspergillus fumigatus) and six material substrates (stainless steel, polymethyl methacrylate, copper, surgical facemask, denim, and a cotton-polyester fabric). The combination of both ozone and UVC generally yields improved performance compared to their respective applications for the range of materials and microorganisms considered. Furthermore, the effectiveness of both UVC and ozone was higher when the fungi utilized were smeared onto the nonabsorbent materials than when 10 μL droplets were placed on the material surfaces. This dependence on the contaminating liquid surface area was not exhibited by the bacteria. This study highlights the necessity of adequate UVC and ozone dosage control as well as their synergistic and multifunctional attributes when sterilizing different materials contaminated with a wide range of microorganisms.

Ozone Decontamination of Medical and Nonmedical Devices: An Assessment of Design and Implementation Considerations

“…Comparative representation of the inactivation mechanisms of selected disinfection methods (adapted from refs and ).…”

“…105 Aqueous Ozone Application Temperature Increased temperature enhances aqueous ozone instability/depletion; at lower temperatures, ozone is more stable. 98,100,106 Increased temperature increases aqueous ozone's reactivity, and inactivation efficiency. 98,100,106 Pressure Increased pressure favors aqueous ozone solubility and stability.…”

“…98,100,106 Increased temperature increases aqueous ozone's reactivity, and inactivation efficiency. 98,100,106 Pressure Increased pressure favors aqueous ozone solubility and stability. 104 Better stability implies prolonged antimicrobial activity in water.…”

Electron-Beam Pumped UVC-Emitters Based on (Al, Ga)N Material System

“…The state of the art in this area has been described in excellent recent reviews [21−23], which indicate that exposure by UVC radiation at 254 or 222 nm with a dose of about 2-6 mJ cm -2 is required to reduce the concentrations of the main pathogenic bacteria by a thousand times. The same UVC radiation can be also used to protect food from bacteriological decay [24,25]. Due to its high biological activity, UV light has several harmful side effects, namely a carcinogenic effect on human skin and developing eye cataracts [26].…”

The synergistic antibacterial activity of ozone and surfactant mists

“…3 The mechanisms of ozone's action are well documented and can be generally classied into direct oxidation (via ozone's interaction with the cell's components) and indirect oxidation involving bacterial exposure to reactive oxidative species (ROS). 4,5 The resultant effect of both routes includes the rupturing of the cell membrane and eventual cell lysis, protein oxidation, DNA damage and the disruption of enzymatic activities. However, the bactericidal effects of these short-lived ROS are mainly evident when an imbalance exists between ROS exposure and the bacteria's antioxidant defences (oxidative stress).…”