Latvian Biomedical Research and Study Centre, Ratsupites Str. 1, Riga, 1067, Latvia.
Institute of Atomic Physics and Spectroscopy, University of Latvia, Jelgavas Str. 3, Riga, 1004, Latvia.
Photochem Photobiol Sci. 2024 Oct;23(10):1841-1856. doi: 10.1007/s43630-024-00634-2. Epub 2024 Sep 21.
Disinfection with LED lamps is a promising ecological and economical substitute for mercury lamps. However, the optimal time/dose relationship needs to be established. Pathogen inactivation by UV-A primarily relies on induced reactive oxygen species (ROS) formation and subsequent oxidative damage. While effective against bacteria and enveloped viruses, non-enveloped viruses are less sensitive. In this study, we explored the disinfection properties of 10 W UV-A LED, emitting in the 365-375 nm range. UV-A at high values of irradiance (~ 0.46 W/cm) can potentially induce ROS formation and direct photochemical damage of the pathogen nucleic acids, thus improving the disinfection. The UV-A inactivation was evaluated for the bacterium Escherichia coli (E. coli), non-enveloped RNA bacteriophage MS2, and enveloped mammalian RNA virus-Semliki Forest virus (SFV). The 4 log10 reduction doses for E. coli and SFV were 268 and 241 J/cm, respectively. Furthermore, in irradiated E. coli, ROS production positively correlated with the inactivation rate. In the case of MS2 bacteriophage, the 2.5 log10 inactivation was achieved by 679 J/cm within 30 min of irradiation. The results demonstrate significant disinfection efficiency of non-enveloped virus MS2 using high-irradiance UV-A. This suggests a potential strategy for improving the inactivation of UV-A-unsusceptible pathogens, particularly non-enveloped viruses. Additionally, the direct UV-A irradiation of self-replicating viral RNA from SFV led to a significant loss of viral gene expression in cells transfected with the irradiated RNA. Therefore, the virus inactivation mechanism of high-irradiance UV-A LED can be partially determined by the direct damage of viral RNA.
LED 灯消毒是一种有前途的生态和经济替代汞灯的方法。然而，需要建立最佳的时间/剂量关系。UV-A 对病原体的灭活主要依赖于诱导活性氧（ROS）的形成和随后的氧化损伤。虽然对细菌和包膜病毒有效，但非包膜病毒的敏感性较低。在这项研究中，我们探索了发出 365-375nm 范围的 10W UV-A LED 的消毒特性。高辐照度（~0.46 W/cm）的 UV-A 可能会诱导 ROS 的形成，并直接对病原体的核酸进行光化学损伤，从而提高消毒效果。我们评估了 UV-A 对细菌大肠杆菌（E. coli）、非包膜 RNA 噬菌体 MS2 和包膜哺乳动物 RNA 病毒-森布利基森林病毒（SFV）的灭活效果。大肠杆菌和 SFV 的 4 log10 减少剂量分别为 268 和 241 J/cm。此外，在辐照的大肠杆菌中，ROS 的产生与失活动率呈正相关。对于 MS2 噬菌体，在 30 分钟的辐照下，通过 679 J/cm 即可实现 2.5 log10 的灭活。结果表明，高辐照度 UV-A 对非包膜病毒 MS2 具有显著的消毒效率。这表明了一种提高对 UV-A 不敏感病原体（特别是非包膜病毒）灭活效率的潜在策略。此外，SFV 的自我复制病毒 RNA 直接受到 UV-A 的辐照，导致转染了辐照 RNA 的细胞中病毒基因表达显著丧失。因此，高辐照度 UV-A LED 的病毒灭活机制部分可以通过病毒 RNA 的直接损伤来确定。
