UV 254 nm is more efficient than UV 222 nm in inactivating SARS-CoV-2 present in human saliva

Sesti-Costa, Renata; Negrão, Cyro von Zuben; Shimizu, Jacqueline Farinha; Nagai, Alice; Tavares, Renata Spagolla Napoleão; Adamóski, Douglas; Costa, Wanderley; Fontoura, Marina Alves; Silva, Thiago Jasso da; Barros, Adriano de; Girasole, Alessandra; Carvalho, Murilo; Teixeira, Verônica C.; Granja, Fabiana; Proença-Módena, José Luiz; Marques, Rafael Elias; Dias, Sandra Martha Gomes

doi:10.1016/j.pdpdt.2022.103015

Cited by 14 publications

(9 citation statements)

References 34 publications

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“…Another study also reported that the inactivation rate constant of SARS-CoV-2 in buffered deionized water is 1.8-fold higher at 222 nm than 254 nm on the same UV fluence basis . The current studies about Far-UVC inactivation of pathogens are mostly conducted using (buffered) deionized water instead of real water (e.g., tap water, surface water, or wastewater effluent). ,,− Sesti-Costa et al reported that the inactivation rate constants of SARS-CoV-2 by Far-UVC radiation decreased dramatically by 400-fold in human saliva than that in buffered deionized water . However, the causes responsible for the decrease were not addressed.…”

Section: Introductionmentioning

confidence: 99%

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Nitrate Protects Microorganisms and Promotes Formation of Toxic Nitrogenous Byproducts during Water Disinfection by Far-UVC Radiation

Wang

et al. 2023

Environ. Sci. Technol.

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Far-UVC radiation is an emerging tool for combating pathogenic microorganisms in water, but its vulnerability to water matrix components remains unclear. We herein report the critical impacts of nitrate during Far-UVC disinfection of water. Nitrate at environmentally relevant concentrations (0.5−10.0 mg-N L −1 ) significantly inhibits Escherichia coli inactivation by Far-UVC radiation at 222 nm, via prolonging the "lag phase" of inactivation and reducing the inactivation rate constants by 1.08−2.74 times, while it shows negligible impact on E. coli inactivation by UVC radiation at 254 nm. The inhibitory impact of nitrate on Far-UVC disinfection is attributed to its strong light-shielding effect. Although hydroxyl radicals and reactive nitrogen species are generated from Far-UVC photolysis of nitrate at high concentrations of 10 −13 and ∼10 −7 M, respectively, those radicals are unable to compensate for the light-shielding effect of nitrate on E. coli inactivation. Moreover, reactive nitrogen species lead to the formation of nitrogenous byproducts, which increase the genotoxicity of the water. The findings advance the fundamental photochemistry and radical chemistry of nitrate at 222 nm and provide useful insights to guide the operation of Far-UVC in treating nitrate-containing water.

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Section: Introductionmentioning

confidence: 99%

“…13,29,33−38 Sesti-Costa et al reported that the inactivation rate constants of SARS-CoV-2 by Far-UVC radiation decreased dramatically by 400-fold in human saliva than that in buffered deionized water. 45 However, the causes responsible for the decrease were not addressed.…”

Section: Introductionmentioning

confidence: 99%

Nitrate Protects Microorganisms and Promotes Formation of Toxic Nitrogenous Byproducts during Water Disinfection by Far-UVC Radiation

Wang

et al. 2023

Environ. Sci. Technol.

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“…Several recent papers have focused on krypton-chloride excimer (KrCl) lamps that exhibit a dominant peak at ~222 nm [12,16,24]. Many studies have evaluated the impact of UV 222 nm on human and animal cells, skin, and eyes [18] and parameters such as cell number/viability, epidermal thickening, CPD and 6,4-PP levels, and erythema formation.…”

Section: Discussionmentioning

confidence: 99%

“…Two test apparatuses were designed, optimized, fabricated, and calibrated to enable accurate and controlled UV-C treatment (at 254 nm or 222 nm) [24] of the RHS samples and acute irradiation of the mice. The RHS was kept within the inserts and placed in the middle of a 30 mm Petri dish containing 3 mL of Dermal Cell Basal Medium (ATCC® PCS-200-030™).…”

Section: Uv-c Devices and Irradiation Assaysmentioning

confidence: 99%

Different biological effects of exposure to far-UVC (222 nm) and near-UVC (254 nm) irradiation

Tavares

Adamóski

Girasole

et al. 2022

Preprint

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Ultraviolet C (UVC) light has long been used as a sterilizing agent, primarily through devices that emit at 254 nm. Depending on the dose and duration of exposure, UV 254 nm can cause erythema and photokeratitis and potentially cause skin cancer since it directly modifies nitrogenated nucleic acid bases. Filtered KrCl excimer lamps (emitting mainly at 222 nm) have emerged as safer germicidal tools and have even been proposed as devices to sterilize surgical wounds. All the studies that showed the safety of 222 nm analyzed cell number and viability, erythema generation, epidermal thickening, the formation of genetic lesions such as cyclobutane pyrimidine dimers (CPDs) and pyrimidine-(6-4)-pyrimidone photoproducts (6-4PPs) and cancer-inducing potential. Although nucleic acids can absorb and be modified by both UV 254 nm and UV 222 nm equally, compared to UV 254 nm, UV 222 nm is more intensely absorbed by proteins (especially aromatic side chains), causing photooxidation and cross-linking. Here, in addition to analyzing DNA lesion formation, for the first time, we evaluated changes in the proteome and cellular pathways, reactive oxygen species formation, and metalloproteinase (MMP) levels and activity in full-thickness in vitro reconstructed human skin (RHS) exposed to UV 222 nm. We also performed the longest (40 days) in vivo study of UV 222 nm exposure in the HRS/J mouse model at the occupational threshold limit value (TLV) for indirect exposure (25 mJ/cm2) and evaluated overall skin morphology, cellular pathological alterations, CPD and 6-4PP formation and MMP-9 activity. Our study showed that processes related to reactive oxygen species and inflammatory responses were more altered by UV 254 nm than by UV 222 nm. Our chronic in vivo exposure assay using the TLV confirmed that UV 222 nm causes minor damage to the skin. However, alterations in pathways related to skin regeneration raise concerns about direct exposure to UV 222 nm.

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“…Far UV‐C mediated inactivation of microorganisms is summarized elsewhere (34). Recently, a report indicated that 222 nm UV is less efficient than the 254 nm UV in inactivating severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) in human saliva (35). Further, the required dose for inactivating SARS‐CoV‐2 in saliva is 30 times higher than that required to inactivate it in saline solution (PBS).…”

Section: Potency Of Shorter Wavelength Uv‐c On Inactivation Of Microo...mentioning

confidence: 99%

Biological Impact of Shorter Wavelength Ultraviolet Radiation‐C^†

Nishigori

Yamano

Kunisada

et al. 2022

Photochem & Photobiology

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Life on earth has constantly coped with the impact of solar radiation, especially solar ultraviolet radiation (solar UV). Various biological mechanisms protect us from solar UV. New devices emitting shorter wavelengths UV-C, i.e. <254 nm emitted by conventional UV germicidal lamps, have emerged. These shorter wavelength UV-C emitting devices are useful for various purposes, including microorganism inactivation. However, as solar UV-C does not reach the earth surface, biological impacts of UV-C has been studied using 254 nm germicidal lamps, and those using shorter wavelength UV-C is rarely known. To balance the utility and risk of UV-C, the biological effect of these new UV-C emitting devices must be investigated. In addition, our knowledge of biological impacts of the wavelength-dependent entire UV (100-400 nm) must be enhanced. In this review, we briefly summarize the biological impacts of shorter wavelength UV-C. Mechanisms of UV-C-induced cellular damage and factors affecting the microorganism inactivation efficiency of UV-C have been discussed. In addition, we theoretically estimate the probable photocarcinogenic action spectrum of shorter wavelength UV-C. We propose that increasing the knowledge on UV-C will facilitate the adoption of shorter wavelength UV-C emitting new devices in an optimal and appropriate manner.

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UV 254 nm is more efficient than UV 222 nm in inactivating SARS-CoV-2 present in human saliva

Cited by 14 publications

References 34 publications

Nitrate Protects Microorganisms and Promotes Formation of Toxic Nitrogenous Byproducts during Water Disinfection by Far-UVC Radiation

Nitrate Protects Microorganisms and Promotes Formation of Toxic Nitrogenous Byproducts during Water Disinfection by Far-UVC Radiation

Different biological effects of exposure to far-UVC (222 nm) and near-UVC (254 nm) irradiation

Biological Impact of Shorter Wavelength Ultraviolet Radiation‐C^†

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UV 254 nm is more efficient than UV 222 nm in inactivating SARS-CoV-2 present in human saliva

Cited by 14 publications

References 34 publications

Nitrate Protects Microorganisms and Promotes Formation of Toxic Nitrogenous Byproducts during Water Disinfection by Far-UVC Radiation

Nitrate Protects Microorganisms and Promotes Formation of Toxic Nitrogenous Byproducts during Water Disinfection by Far-UVC Radiation

Different biological effects of exposure to far-UVC (222 nm) and near-UVC (254 nm) irradiation

Biological Impact of Shorter Wavelength Ultraviolet Radiation‐C†

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Product

Resources

About

Biological Impact of Shorter Wavelength Ultraviolet Radiation‐C^†