Improved Spectral Purity of 222‐nm Irradiation Eliminates Detectable Cyclobutylpyrimidine Dimers Formation in Skin Reconstructs even at High and Repetitive Disinfecting Doses. (5th February 2022)

• Record Type: Journal Article
• Authors: Ivanova, Irina; Svilenska, Teodora; Kurz, Bernadett; Grobecker, Sonja; Maisch, Tim; Berneburg, Mark; Kamenisch, York
• Is Part Of: Photochemistry and photobiology. Volume 98:Number 5(2022)
• Page Start: 1149
• Page End: 1156
• Publication Date: 2022-02-05
• Subjects: Photochemistry -- Periodicals; Light -- Physiological effect -- Periodicals; 541.35
• DOI: 10.1111/php.13594
• Languages: English
• ISSNs: 0031-8655

Abstract

Abstract: UVC222 nm has germicidal effects with potential clinical applications. However, UVC irradiation is capable of inducing DNA damage like cyclobutylpyrimidine dimers (CPD). Although new devices have emission peaks in the short‐wavelength region of UVC (~222 nm), the remaining "collateral" radiation at longer wavelengths could be harmful to human health. We investigated the DNA damage caused by far‐UVC 222 nm KrCl exciplex radiation on human skin reconstructs after additional filtering using silica filters. The skin reconstructs were irradiated with 100 mJ cm −2, 500 mJ cm −2, and 3 × 500 mJ cm −2 unfiltered and filtered (230–270 nm suppressed) far‐UVC or UVB (308 nm) radiation. UVB and non‐filtered UVC irradiation induced a significant amount of CPDs, compared with the background. Filtered far‐UVC lowered the CPD amount compared with unfiltered UVC and UVB treatments. Repetitive UVC irradiation did not result in the accumulation of CPDs compared with UVB treatment. Reduction in excess of 99.9% of E. coli, S. aureus and C . albicans was detected after applying far‐UVC radiation. This identifies a therapeutic window in which microorganisms are killed but tissue is still alive and not damaged, which could give rise to new clinical applications. Abstract : Human skin reconstructs were irradiated with single (100 mJ cm −2, 500 mJ cm −2 ) and repetitive (3 × 500 mJ cm −2 ) doses of 222 nm far‐UVC or with UVB (308 nm). UVB and non‐filtered far‐UVC induced significant amounts of CPDs, compared with non‐treated samples. After the application of filters (1F/2F, blocking range: 230–270 nm), the amount of CPDs in far‐UVC treatments decreased. In addition, an antimicrobial effect (99.9% reduction of colony‐forming units) of the filtered far‐UVC (2F) against E. coli, S. aureus and Candida albicans could be demonstrated. With this, a therapeutic window has been identified in which microorganisms are killed but tissue is alive and undamaged.