[ODP-217] Microbicidal effect of deep ultraviolet light-emitting diode irradiation
Purpose: A deep ultraviolet light-emitting diode (DUV-LED) was developed that emits light of a wavelength of 200 to 300 nm. We examined microbicidal effect of 265-nm and 280-nm DUV-LEDs.
Methods: Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, vegetative form and spore form of Bacillus subtilis, and Candida albicans were used for experiments. Microbicidal effect by DUV-LED light was analyzed quantitatively using colony-forming ability as an index. DNA damage was evaluated by formation of pyrimidine dimers (CPD and 6-4PP) with ELISA.
Results: DUV-LED lights whose peak wavelengths were 265 and 280 nm showed similar microbicidal effects on microorganisms in a time-dependent manner. In the quantitative test with 265-nm DUV-LED light, the irradiation time at which survival rate was 0% was 20 s for P. aeruginosa, 30 s for E. coli, 180 s for S. aureus and C. albicans, 300 s for vegetative form of B. subtilis, and 420 s for spore. CPD and 6-4PP were detected in DNA samples from all microorganisms irradiated with DUV-LED light.
Conclusion: DUV-LED light showed microbicidal effect by DNA damage with formation of pyrimidine dimers. Sensitivity to DUV-LED light was in the order of P. aeruginosa > E. coli > S. aureus > C. albicans > vegetative form of B. subtilis > spore form of B. subtilis. DUV-LED devices can potentially be useful tools for inactivation of microorganisms.
Methods: Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, vegetative form and spore form of Bacillus subtilis, and Candida albicans were used for experiments. Microbicidal effect by DUV-LED light was analyzed quantitatively using colony-forming ability as an index. DNA damage was evaluated by formation of pyrimidine dimers (CPD and 6-4PP) with ELISA.
Results: DUV-LED lights whose peak wavelengths were 265 and 280 nm showed similar microbicidal effects on microorganisms in a time-dependent manner. In the quantitative test with 265-nm DUV-LED light, the irradiation time at which survival rate was 0% was 20 s for P. aeruginosa, 30 s for E. coli, 180 s for S. aureus and C. albicans, 300 s for vegetative form of B. subtilis, and 420 s for spore. CPD and 6-4PP were detected in DNA samples from all microorganisms irradiated with DUV-LED light.
Conclusion: DUV-LED light showed microbicidal effect by DNA damage with formation of pyrimidine dimers. Sensitivity to DUV-LED light was in the order of P. aeruginosa > E. coli > S. aureus > C. albicans > vegetative form of B. subtilis > spore form of B. subtilis. DUV-LED devices can potentially be useful tools for inactivation of microorganisms.