Far-UVC- and UVB-induced DNA damage depending on skin type

Area of Science:

• Photomedicine
• Dermatology
• Molecular Biology

Background:

• Far-UVC radiation (222-233 nm) offers potential for skin antiseptic treatments due to high compatibility.
• Limited research exists on far-UVC's impact on DNA damage across diverse skin types.

Purpose of the Study:

• To investigate far-UVC-induced DNA damage in various skin types.
• To compare DNA damage from 222 nm, 233 nm, and broadband UVB radiation.
• To explore the role of melanin in differential photoprotection.

Main Methods:

• Skin irradiation with 222 nm, 233 nm far-UVC, and broadband UVB.
• Immunohistochemistry to detect cyclobutane pyrimidine dimer-positive (CPD+) cells.
• Two-photon excited fluorescence lifetime imaging (TPE-FLIM) to quantify melanin distribution.

Main Results:

• 233 nm far-UVC induced less epidermal DNA damage in darker skin types compared to fair skin.
• 222 nm far-UVC showed no significant skin type-dependent DNA damage differences.
• UVB exhibited the most pronounced skin type differences in DNA damage.
• Higher melanin ratios in stratum basale/granulosum (up to skin type IV-V) were observed.

Conclusions:

• Far-UVC's limited penetration and melanin's photoprotective effect explain reduced skin type differences compared to UVB.
• 222 nm and 233 nm far-UVC show promise for antiseptic skin treatment with minimal differential effects across skin types.