A research team from Mie University in Japan has found that early zebrafish embryos (embryos several hours after fertilization) can be safely irradiated with 278 nm UVC.
UVC-LEDs around 260nm are used for sterilization as they induce and inactivate DNA damage from bacteria and viruses. Most of the current research focuses on the effect of UVC with wavelengths below 240nm (207nm, 222nm, 233nm) on killing the new coronavirus. However, there are few studies on the toxicity, safety, and response of organisms to UVC irradiation around 280 nm.
Therefore, this time, a total of 16 irradiation doses were set in the range of 0.5 to 60 mJ/cm² using the irradiation device developed by the research group to irradiate 278 nm UVC, and zebrafish embryos were directly irradiated.
After 3 days of irradiation, the researchers evaluated the survival rate, hatching rate, heart rate, deformity rate, etc. of zebrafish embryos. The results found that all embryos remained alive under the irradiation dose below 4.5mJ/cm². However, when the dose reached 7.5 mJ/cm², the deformity rate significantly increased to 82 percent , and the survival rate decreased to 37 percent . Embryo death was observed if the dose was increased to 10 mJ/cm² and above.
Based on the above experimental results, the researchers determined that there is a biological defense system inside the zebrafish embryo, which can resist the damage caused by UVC irradiation to the greatest extent, and the limit dose that can resist UVC irradiation is 4.5 mJ/cm².
The researchers believe that the biological defense mechanism of zebrafish against UVC-induced DNA damage is that after zebrafish embryos are treated with UVC at a dose of 4.5 mJ/cm², the p53 signaling pathway in cells is immediately and urgently activated. Arrest, DNA repair, cell division/proliferation and damaged cell death in rapid response to stress. In addition, after 3 days of recovery, p53 variability was attenuated and instead activated the STAT signaling pathway, which continued to repair damaged DNA.
The research results of this subject provide a scientific basis for the safety of UVC-LED applied to the human body. At the same time, the research team found that UVC is suitable for the disinfection of bacteria and viruses including coronavirus, as well as disinfection in aquaculture.
"Experts say UV" believes that: at the application level, the sterilization experience of UVC-LED is difficult to intuitively perceive, and consumers will have concerns about safety when using it. brings confidence.
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