Evaluation of DNA lesions and radicals generated by a 233 nm far-UVC LED in superficial ex vivo skin wounds

Loris Busch; Marius Kröger; Johannes Schleusener; Anna Lena Klein; Silke B Lohan; Martin Guttmann; Cornelia M Keck; Martina C Meinke

doi:10.1016/j.jphotobiol.2023.112757

Evaluation of DNA lesions and radicals generated by a 233 nm far-UVC LED in superficial ex vivo skin wounds

J Photochem Photobiol B. 2023 Aug:245:112757. doi: 10.1016/j.jphotobiol.2023.112757. Epub 2023 Jul 18.

Authors

Loris Busch¹, Marius Kröger², Johannes Schleusener², Anna Lena Klein², Silke B Lohan², Martin Guttmann³, Cornelia M Keck⁴, Martina C Meinke²

Affiliations

¹ Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Dermatology, Venereology and Allergology, Center of Experimental and Applied Cutaneous Physiology, Charitéplatz 1, 10117 Berlin, Germany; Philipps-Universität Marburg, Department of Pharmaceutics and Biopharmaceutics, Robert-Koch-Str. 4, 35032 Marburg, Germany. Electronic address: loris.busch@charite.de.
² Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Dermatology, Venereology and Allergology, Center of Experimental and Applied Cutaneous Physiology, Charitéplatz 1, 10117 Berlin, Germany.
³ Ferdinand-Braun-Institut (FBH), Gustav-Kirchhoff-Straße 4, 12489 Berlin, Germany.
⁴ Philipps-Universität Marburg, Department of Pharmaceutics and Biopharmaceutics, Robert-Koch-Str. 4, 35032 Marburg, Germany.

PMID: 37481791
DOI: 10.1016/j.jphotobiol.2023.112757

Abstract

The application of a far-ultraviolet C (UVC) light emitting diode (LED) of 233 nm showed significant bactericidal efficacy at an applied dose between 20 and 80 mJ cm^-2 as reported recently. In addition, only minor epidermal DNA lesions were observed in ex vivo human skin and in vitro epidermal models <10% of the minimal erythema dose of UVB radiation. To broaden the potential range of applications of such systems, e.g. to include postoperative application on wounds for the purpose of decontamination, we assessed how a disruption of normal anatomic skin structure and function influences the skin damage induced by light from 233 nm far-UVC LEDs. Thus, we induced superficial skin wounds by mechanical detachment of the stratum corneum in ex vivo human skin. Barrier-disruption of the skin could be successfully determined by measuring an increase in the transepidermal water loss (TEWL) and the stratum corneum loss could be determined morphologically by 2-photon microscopy (2-PM). After far-UVC irradiation of the skin, we screened the tissue for the development of cyclobutane pyrimidine dimers (CPDs) and 6-4 photoproducts (6-4PPs). The abundance of DNA lesions was elevated in wound skin in comparison to intact skin after irradiation with far-UVC. However, no increase in DNA lesions was detected when artificial wound exudate consisting of cell culture medium and serum was applied to the disrupted skin surface prior to irradiation. This effect agrees with the results of ray tracing simulations of the absorption of far-UVC light incident on a superficial skin wound. Interestingly, no significant deviations in radical formation between intact skin and superficially wounded skin were detected after far-UVC irradiation as analyzed by electron paramagnetic resonance (EPR) spectroscopy. In conclusion, 233 nm LED light at a dose of 60 mJ/cm² could be applied safely on superficial wounds for the purpose of skin antisepsis as long as the wounds are covered with wound fluid.

Keywords: DNA damage; Far-UVC; Free radicals; LED; Ray tracing simulation; Skin wounds.

MeSH terms

DNA / metabolism
DNA Damage
Epidermis
Humans
Pyrimidine Dimers* / metabolism
Skin* / radiation effects
Ultraviolet Rays

Substances

Pyrimidine Dimers
DNA