Viral Inactivation by Light-Emitting Diodes: Action Spectra Reveal Genomic Damage as the Primary Mechanism

Area of Science:

• Microbiology
• Biophysics
• Public Health

Background:

• Ultraviolet light-emitting diodes (UV-LEDs) offer a promising approach for viral inactivation.
• Limited understanding exists regarding wavelength-dependent action spectra for UV-LEDs against various viral components.

Purpose of the Study:

• To establish standardized UV action spectra for infectivity reduction in pathogenic viruses using UV-LEDs.
• To determine the relationship between UV-LED exposure, viral genome damage, and protein degradation.
• To identify optimal wavelengths for efficient viral inactivation.

Main Methods:

• Utilized a system with interchangeable LEDs emitting at 13 different peak wavelengths (250-365 nm).
• Measured the reduction in viral infectivity and analyzed viral genome damage and structural protein integrity post-exposure.
• Tested a range of pathogenic viruses, including enveloped and nonenveloped types.

Main Results:

• Viral infectivity reduction strongly correlated with viral genome damage, with no significant degradation of structural proteins observed.
• Peak virucidal efficiency occurred at 267-270 nm, a slight shift from the typical 260 nm nucleic acid absorption peak.
• Enveloped RNA viruses (e.g., influenza, coronavirus) showed higher UV sensitivity than nonenveloped viruses (e.g., calicivirus, adenovirus).

Conclusions:

• Viral structural characteristics, including the presence of an envelope and genome organization, significantly influence UV susceptibility.
• Established wavelength-specific action spectra provide crucial data for optimizing UV-LED disinfection systems.
• Optimized UV-LED systems can enhance viral inactivation efficiency while minimizing energy use in healthcare, food safety, and environmental sanitation.