A Comprehensive Analysis of the UVC LEDs’ Applications and Decontamination Capability

Abstract

The application of light-emitting diodes (LEDs) has been gaining popularity over the last decades. LEDs have advantages compared to traditional light sources in terms of lifecycle, robustness, compactness, flexibility, and the absence of non-hazardous material. Combining these advantages with the possibility of emitting Ultraviolet C (UVC) makes LEDs serious candidates for light sources in decontamination systems. Nevertheless, it is unclear if they present better decontamination effectiveness than traditional mercury vapor lamps. Hence, this research uses a systematic literature review (SLR) to enlighten three aspects: (1) UVC LEDs’ application according to the field, (2) UVC LEDs’ application in terms of different biological indicators, and (3) the decontamination effectiveness of UVC LEDs in comparison to conventional lamps. UVC LEDs have spread across multiple areas, ranging from health applications to wastewater or food decontamination. The UVC LEDs’ decontamination effectiveness is as good as mercury vapor lamps. In some cases, LEDs even provide better results than conventional mercury vapor lamps. However, the increase in the targets’ complexity (e.g., multilayers or thicker individual layers) may reduce the UVC decontamination efficacy. Therefore, UVC LEDs still require considerable optimization. These findings are stimulating for developing industrial or final users’ applications.

Kinetics of inactivation of bacteria responsible for infections in hospitals using UV-LED

“…Nevertheless, it should be taken into consideration that bacteriophages are widely used as model organisms to evaluate the virucidal activity of UV-C light, particularly for surface disinfection [ 27 ]. In addition, according to ISO 14937, we fulfil the criteria of microorganism selection by testing not only strains belonging to the ESKAPEE group but also representative Gram-positive and Gram-negative bacteria, spores and biofilm bacteria producers [ 26 ]. According to the literature, UVC-LED lamps emitting at both 280 nm and 275 nm wavelengths can effectively inactivate a variety of microbial indicators.…”

“…Based on the ISO 14937: Sterilization of health care products — General requirements for characterization of a sterilizing agent and the development, validation and routine control of a sterilization process for medical devices (Annex A ISO 14937), Escherichia coli DSM 30083, Staphylococcus aureus DSM 20231, Bacillus subtillis DSM 10 Pseudomonas aeruginosa DSM 1117 and Escherichia phage lambda (Enterobacteria phage lambda) DSM 4499 and its host bacterium Escherichia coli DSM 4230 were selected to be used in UV-LED inactivation experiments as microbiological indicators of disinfection due their relevance in nosocomial infections [ 26 , [38] , [39] , [40] ]. All the type strains were obtained from the Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures GmbH, Braunschweig, Germany.…”

“…Additionally, the physical mode of action of UV disinfection may limit its ability to penetrate different surfaces and materials, such as solid masses or opaque liquids, which could compromise its efficacy. Furthermore, the wavelength of the UV radiation requires testing in case of uncertainty for sensitive materials [ 25 , 26 ]. In addition, in facilities such as hospitals, the irradiation time should be adjusted to account for room dimensions and complexity [ 25 , 27 ].…”

Low-power blue LED and red laser effects on plasmid DNA, survival, and photolyase mRNA levels in Escherichia coli cultures

“…Due to the UVC-induced bactericidal effect, several disinfection methods are based on UVC LED and UVC lamp treatment systems [13]. Disinfection based on UVC systems helps inactivate pathogens in food, water, and beverages [13][14][15]. In healthcare and hospital settings, UVC has been used on room surfaces to inactivate pathogens that can cause infections by multidrug-resistant bacteria [16].…”

Theoretical modeling and design aspects of cubic-phase GaN homojunction-based UVC light sensor

“…Thus, due to the capability of UVC to interact with DNA 2 . In addition, UVC has applications in air disinfection, 3 , 4 water disinfection, 5 as a germicide for agriculture, 6 and flame detection 7 . Since UVC is a hazard for humans during its application, UV photodetectors must be developed to alert people to the presence of UV radiation to avoid possible exposure.…”