Virus inactivation and skin safety studies using far-UVC LEDs
David Welch1, Manuela Buonanno1, Camryn Petersen1
1Center for Radiological Research, Columbia University Irving Medical Center, New York, New York, USA.
Photochemistry and Photobiology
|May 9, 2025
Summary
New far-UVC LEDs (233 nm) effectively inactivate airborne viruses and show reduced DNA damage in skin models compared to traditional UV lamps. This technology offers a promising solution for reducing disease transmission in occupied spaces.
Area of Science:
- Microbiology
- Photobiology
- Public Health
Background:
- Airborne disease transmission poses a significant public health challenge.
- Far-ultraviolet C (Far-UVC) light (200-235 nm) is being explored for its potential to inactivate pathogens in occupied environments.
- The efficacy and safety of emerging Far-UVC light-emitting diodes (LEDs) require thorough investigation.
Purpose of the Study:
- To evaluate the virus inactivation efficacy of state-of-the-art Far-UVC LEDs (233 nm) against a surrogate for SARS-CoV-2.
- To assess the potential for DNA damage in human skin models exposed to 233 nm Far-UVC light.
- To compare the safety and efficacy of 233 nm Far-UVC LEDs with conventional 254 nm UV sources.
Main Methods:
- Utilized 233 nm Far-UVC LEDs to expose aerosolized human coronavirus OC43 (HCoV-OC43) and HCoV-OC43 dried on surfaces.
- Quantified virus inactivation by determining susceptibility constants (k) and D90 values.
- Exposed human skin biopsies to 100 mJ/cm² of 233 nm Far-UVC light and 254 nm UV light, assessing DNA damage markers.
Main Results:
- The 233 nm Far-UVC LEDs demonstrated effective inactivation of aerosolized HCoV-OC43 with a susceptibility constant of k₂₃₃-aerosol = 4.0 ± 0.2 cm²/mJ (D90 = 0.58 mJ/cm²).
- Inactivation efficacy on dried HCoV-OC43 on plastic and glass surfaces was comparable to aerosolized virus (k₁₂₃₃-plastic = 6.7 ± 3.8 cm²/mJ, k₁₂₃₃-glass = 7.2 ± 3.0 cm²/mJ).
- Exposure to 100 mJ/cm² of 233 nm Far-UVC light resulted in DNA damage in only 8% of epidermal cells, significantly lower than 45% damage observed with 254 nm UV light, with no double-strand breaks detected.
Conclusions:
- 233 nm Far-UVC LEDs are effective in inactivating airborne and surface-dried HCoV-OC43.
- The 233 nm Far-UVC LEDs exhibit a favorable safety profile with minimal DNA damage to skin models compared to 254 nm UV.
- These findings support the continued development and application of 233 nm Far-UVC LED technology for public health applications in reducing disease transmission.
