Opto-Electronic Advances, Volume. 6, Issue 9, 230154(2023)

Recent developments in deep-ultraviolet sterilization of human respiratory RNA viruses

Tingzhu Wu1,2、†, Shouqiang Lai1、†, Zhong Chen1,2, and Hao-Chung Kuo3,4、*
Author Affiliations
  • 1National Integrated Circuit Industry and Education Integration Innovation Platform, Department of Electronic Science, Xiamen University, Xiamen 361005, China
  • 2Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen 361005, China
  • 3College of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, China
  • 4Semiconductor Research Center, Hon Hai Research Institute, Taipei 11492, China
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    Deep-ultraviolet (DUV) sterilization technology using DUV-LEDs has attracted considerable attention owing to its portability, eco-friendliness, high potency, and broad-spectrum sterilization. This study compiles the developments of recent DUV sterilization research. Recent works have investigated DUV sterilization from the perspective of device improvement and principle investigation: one employed a novel epitaxial structure to optimize the performance and fabrication cost of DUV-LEDs and realized potent virus disinfection effects for various respiratory RNA viruses, and another work explained the disinfection phenomenon of SARS-CoV-2 and its variants (Delta and Omicron) in a cryogenic environment. These studies have contributed significantly to the development of DUV sterilization.

    To relax the SCS in DUV-LEDs grown on HTA AlN/sapphire templates, Li et al.1 proposed a novel epitaxial structure of DUV-LEDs with AlN/AlGaN superlattices (SLs); the structure diagram is shown in Fig. 1(a). The X-ray diffraction reciprocal space mapping (XRD-RSM) of DUV-LEDs without and with SLs are shown in Fig. 1(b–c), respectively, indicating that the wafer with SLs has a relaxation ratio of ~60%. Moreover, to determine whether the inactivation effect of DUV-LEDs differs between virus mutations, pseudotyped SARS-CoV-2 viruses with different mutated spike proteins on their surfaces were used for the irradiation assay. Figure 1(d) indicates that the inactivation effects of 256 nm LEDs are not disrupted by changes in viral outer membrane proteins. These results contribute to the development of advanced DUV-LEDs for the disinfection of viruses.

    These studies contribute to the development of portable, long-lasting, and broad-spectrum DUV-LED sterilization applications for disinfecting human respiratory RNA viruses, fill the research gaps regarding the differences in SARS-CoV-2 and its variants (Delta and Omicron), and clarify the influences of the cryogenic environment on DUV virucidal efficacy. Future work could research new types of DUV light sources, such as high-density GaN/AlN quantum dots or directional high-efficiency nanowire LEDs, and investigate the principle of surface roughness or nanoparticle size for DUV sterilization7.

    (a) Structure diagram of DUV-LED with SLs. (b−c) XRD-RSMs of the (−105) planes for wafers without and with SLs, respectively. (d) Inactivation effects of 256-nm DUV-LED for different SARS-CoV-2 variants.1

    Figure 1.(a) Structure diagram of DUV-LED with SLs. (bc) XRD-RSMs of the (−105) planes for wafers without and with SLs, respectively. (d) Inactivation effects of 256-nm DUV-LED for different SARS-CoV-2 variants.1

    DUV sterilization technology has been widely studied for the inactivation of human respiratory RNA viruses. However, many obstacles remain in the development of DUV sterilization with DUV-LEDs, which can be divided into three groups. First, fabricating DUV-LEDs on high-temperature-annealed (HTA) AlN/sapphire templates introduces strong compressive stress (SCS) and deteriorates their external quantum efficiency (EQE), whereas fabricating DUV-LEDs using AlN single-crystal substrate is too expensive for industrial application; thus, the luminous efficiency and fabrication cost of high-power DUV-LED light sources require further optimization3, 4. Second, the differences in the virucidal efficacy of DUV on SARS-CoV-2 and its variants (Delta and Omicron) under the same dose is unknown5. Third, the principle of the lethal effect of DUV on SARS-CoV-2 and its variants in a cryogenic environment (e.g., food cold chain logistics and outside in winter) has not been clearly demonstrated6.

    (a) Influence of Omicron variant on DUV disinfection on (a) gene sequence and (b) proteins. (c) Influence of low- (left) and high-temperatures (right) on DUV disinfection.6

    Figure 2.(a) Influence of Omicron variant on DUV disinfection on (a) gene sequence and (b) proteins. (c) Influence of low- (left) and high-temperatures (right) on DUV disinfection.6

    To clarify the influence of SARS-CoV-2 and its variants on DUV virucidal efficacy, the effect of DUV disinfection on the Omicron variant was analyzed by Kang et al.6 They attributed the differences to two possibilities: gene sequence (Fig. 2(a)) and protein composition (Fig. 2(b)). Figure 2(a) shows the inactivation of (+) single-stranded RNA viruses mainly caused by the formation of uracil/uracil (UU) and uracil/cytosine (UC) dimers after UV radiation, and the final DUV intensity radiated on the viral RNA chains affected by proteins is indicated in Fig. 2(b). In addition, the difference in the extinction coefficient (k) of Omicron affects the absorption and reflectivity for DUV radiation. These factors make Omicron significantly different from other strains.

    Investigations on the influence of temperature on DUV disinfection are essential for DUV applications in cold conditions. Junyong Kang and his colleagues proposed a negative-U large-relaxation model to demonstrate the DUV disinfection process6. A comparison between the low- and high-temperature situations (low or high are relative) is displayed in Fig. 2(c). These results suggest that a cryogenic environment attenuates the lethal effects of DUV radiation.

    Deep-ultraviolet (DUV) photonics is an effective sterilization technology that damages the genomes of human respiratory RNA viruses1. Mercury lamps are conventionally used as DUV light sources for sterilization. However, since the introduction of the Minamata Convention on Mercury in 2020, the manufacture, import, and export of a myriad of products containing mercury have been prohibited. Therefore, AlGaN-based DUV-LEDs, with the advantages of being pollution-free, small, energy-conserving, and having a tunable wavelength, are a perfect alternative to mercury lamps for DUV sterilization2.

    [1] K Jiang, SM Liang, XJ Sun, JW Ben, L Qu et al. Rapid inactivation of human respiratory RNA viruses by deep ultraviolet irradiation from light-emitting diodes on a high-temperature-annealed AlN/sapphire template. Opto-Electron Adv, 230004(2023).

    [2] PO Nyangaresi, Y Qin, GL Chen, BP Zhang, YH Lu et al. Comparison of the performance of pulsed and continuous UVC-LED irradiation in the inactivation of bacteria. Water Res, 218-227(2019).

    [3] SF Liu, Y Yuan, LJ Huang, J Zhang, T Wang et al. Drive high power UVC-LED wafer into low-cost 4-inch era: Effect of strain modulation. Adv Funct Mater, 2112111(2022).

    [4] HPT Nguyen. Graphene-driving novel strain relaxation towards AlN film and DUV photoelectronic devices. Light Sci Appl, 164(2022).

    [5] SSA Karim, QA Karim. Omicron SARS-CoV-2 variant: a new chapter in the COVID-19 pandemic. Lancet, 2126-2128(2021).

    [6] WY Kang, J Zheng, JX Huang, LN Jiang, QN Wang et al. Deep-ultraviolet photonics for the disinfection of SARS-CoV-2 and its variants (Delta and Omicron) in the cryogenic environment. Opto-Electron Adv, 220201(2023).

    [7] LW Chen, MH Hong. Functional nonlinear optical nanoparticles synthesized by laser ablation. Opto-Electron Sci, 210007(2022).

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    Tingzhu Wu, Shouqiang Lai, Zhong Chen, Hao-Chung Kuo. Recent developments in deep-ultraviolet sterilization of human respiratory RNA viruses[J]. Opto-Electronic Advances, 2023, 6(9): 230154

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    Paper Information

    Category: Research Articles

    Received: Aug. 26, 2023

    Accepted: Aug. 28, 2023

    Published Online: Nov. 15, 2023

    The Author Email:

    DOI:10.29026/oea.2023.230154

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