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Wang MH, Wu XM, Lai ACK. Experimental study on the effect of light source arrangements on the disinfection performance of upper-room 222 nm Far-UVC. JOURNAL OF HAZARDOUS MATERIALS 2024; 479:135571. [PMID: 39197280 DOI: 10.1016/j.jhazmat.2024.135571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2024] [Revised: 08/15/2024] [Accepted: 08/16/2024] [Indexed: 09/01/2024]
Abstract
The air disinfection efficacy of upper-room 222 nm Far-UVC was experimentally investigated in a real-size chamber under well-mixed air conditions. Two bacteria (Escherichia coli, Staphylococcus epidermidis) and two bacteriophages (MS2, and P22) were selected for the test. The study considered different lamp source arrangements, including single and double sources, stationary and rotating operating modes, and an overlapping mode with a 45° irradiation angle. A numerical view-factor model was developed to analyze the irradiance distributions. Four irradiation angles, 30°, 45°, 60°, and 90°, were chosen. The results show that the lamps operating with an irradiation angle of 45° provide the highest chamber-averaged irradiance. This suggests an optimal irradiance level for a given room dimension, as inferred from the view factor model. Experimental results indicated that the overlapping mode with a 45° irradiation angle consistently outperformed both the stationary mode and rotating mode in disinfection. This can be attributed to the higher chamber-averaged irradiance, which is also supported by the numerical model predictions. The increment ratios ranged from 14.9 % to 42.9 % compared to the stationary mode. The susceptibility constants of Escherichia coli, Staphylococcus epidermidis, MS2, and P22 were measured as 0.572 m2/J, 0.099 m2/J, 0.060 m2/J, and 0.081 m2/J respectively.
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Affiliation(s)
- M H Wang
- Department of Architecture and Civil Engineering, City University of Hong Kong, Tat Chee Avenue, Hong Kong
| | - X M Wu
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Hong Kong
| | - A C K Lai
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Hong Kong.
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2
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Sinclair LG, Anderson JG, MacGregor SJ, Maclean M. Enhanced antimicrobial efficacy and energy efficiency of low irradiance 405-nm light for bacterial decontamination. Arch Microbiol 2024; 206:276. [PMID: 38777923 PMCID: PMC11111507 DOI: 10.1007/s00203-024-03999-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Revised: 04/28/2024] [Accepted: 05/10/2024] [Indexed: 05/25/2024]
Abstract
Due to its increased safety over ultraviolet light, there is interest in the development of antimicrobial violet-blue light technologies for infection control applications. To ensure compatibility with exposed materials and tissue, the light irradiances and dose regimes used must be suitable for the target application. This study investigates the antimicrobial dose responses and germicidal efficiency of 405 nm violet-blue light when applied at a range of irradiance levels, for inactivation of surface-seeded and suspended bacteria. Bacteria were seeded onto agar surfaces (101-108 CFUplate-1) or suspended in PBS (103-109 CFUmL-1) and exposed to increasing doses of 405-nm light (≤ 288 Jcm-2) using various irradiances (0.5-150 mWcm-2), with susceptibility at equivalent light doses compared. Bacterial reductions ≥ 96% were demonstrated in all cases for lower irradiance (≤ 5 mWcm-2) exposures. Comparisons indicated, on a per unit dose basis, that significantly lower doses were required for significant reductions of all species when exposed at lower irradiances: 3-30 Jcm-2/0.5 mWcm-2 compared to 9-75 Jcm-2/50 mWcm-2 for low cell density (102 CFUplate-1) surface exposures and 22.5 Jcm-2/5 mWcm-2 compared to 67.5 Jcm-2/150 mWcm-2 for low density (103 CFUmL-1) liquid exposures (P ≤ 0.05). Similar patterns were observed at higher densities, excluding S. aureus exposed at 109 CFUmL-1, suggesting bacterial density at predictable levels has minimal influence on decontamination efficacy. This study provides fundamental evidence of the greater energy efficacy of 405-nm light for inactivation of clinically-significant pathogens when lower irradiances are employed, further supporting its relevance for practical decontamination applications.
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Affiliation(s)
- Lucy G Sinclair
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST), Department of Electronic & Electrical Engineering, University of Strathclyde, Glasgow, UK
| | - John G Anderson
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST), Department of Electronic & Electrical Engineering, University of Strathclyde, Glasgow, UK
| | - Scott J MacGregor
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST), Department of Electronic & Electrical Engineering, University of Strathclyde, Glasgow, UK
| | - Michelle Maclean
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST), Department of Electronic & Electrical Engineering, University of Strathclyde, Glasgow, UK.
- Department of Biomedical Engineering, University of Strathclyde, Glasgow, UK.
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Sinclair LG, Ilieva Z, Morris G, Anderson JG, MacGregor SJ, Maclean M. Viricidal Efficacy of a 405-nm Environmental Decontamination System for Inactivation of Bacteriophage Phi6: Surrogate for SARS-CoV-2. Photochem Photobiol 2023; 99:1493-1500. [PMID: 36872097 PMCID: PMC10952546 DOI: 10.1111/php.13798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 03/01/2023] [Indexed: 03/07/2023]
Abstract
The highly transmittable nature of SARS-CoV-2 has increased the necessity for novel strategies to safely decontaminate public areas. This study investigates the efficacy of a low irradiance 405-nm light environmental decontamination system for the inactivation of bacteriophage phi6 as a surrogate for SARS-CoV-2. Bacteriophage phi6 was exposed to increasing doses of low irradiance (~0.5 mW cm-2 ) 405-nm light while suspended in SM buffer and artificial human saliva at low (~103-4 PFU mL-1 ) and high (~107-8 PFU mL-1 ) seeding densities, to determine system efficacy for SARS-CoV-2 inactivation and establish the influence of biologically relevant suspension media on viral susceptibility. Complete/near-complete (≥99.4%) inactivation was demonstrated in all cases, with significantly enhanced reductions observed in biologically relevant media (P < 0.05). Doses of 43.2 and 172.8 J cm-2 were required to achieve ~3 log10 reductions at low density, and 97.2 and 259.2 J cm-2 achieved ~6 log10 reductions at high density, in saliva and SM buffer, respectively: 2.6-4 times less dose was required when suspended in saliva compared to SM buffer. Comparative exposure to higher irradiance (~50 mW cm-2 ) 405-nm light indicated that, on a per unit dose basis, 0.5 mW cm-2 treatments were capable of achieving up to 5.8 greater log10 reductions with up to 28-fold greater germicidal efficiency than that of 50 mW cm-2 treatments. These findings establish the efficacy of low irradiance 405-nm light systems for inactivation of a SARS-CoV-2 surrogate and demonstrate the significant enhancement in susceptibility when suspended in saliva, which is a major vector in COVID-19 transmission.
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Affiliation(s)
- Lucy G. Sinclair
- Department of Electronic & Electrical Engineering, The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST)University of StrathclydeGlasgowUK
| | - Zornitsa Ilieva
- Department of Biomedical EngineeringUniversity of StrathclydeGlasgowUK
| | - Georgina Morris
- Department of Biomedical EngineeringUniversity of StrathclydeGlasgowUK
| | - John G. Anderson
- Department of Electronic & Electrical Engineering, The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST)University of StrathclydeGlasgowUK
| | - Scott J. MacGregor
- Department of Electronic & Electrical Engineering, The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST)University of StrathclydeGlasgowUK
| | - Michelle Maclean
- Department of Electronic & Electrical Engineering, The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST)University of StrathclydeGlasgowUK
- Department of Biomedical EngineeringUniversity of StrathclydeGlasgowUK
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4
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Sinclair LG, Dougall LR, Ilieva Z, McKenzie K, Anderson JG, MacGregor SJ, Maclean M. Laboratory evaluation of the broad-spectrum antibacterial efficacy of a low-irradiance visible 405-nm light system for surface-simulated decontamination. HEALTH AND TECHNOLOGY 2023; 13:1-15. [PMID: 37363345 PMCID: PMC10264887 DOI: 10.1007/s12553-023-00761-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 05/30/2023] [Indexed: 06/28/2023]
Abstract
Purpose Lighting systems which use visible light blended with antimicrobial 405-nm violet-blue light have recently been developed for safe continuous decontamination of occupied healthcare environments. This paper characterises the optical output and antibacterial efficacy of a low irradiance 405-nm light system designed for environmental decontamination applications, under controlled laboratory conditions. Methods In the current study, the irradiance output of a ceiling-mounted 405-nm light source was profiled within a 3×3×2 m (18 m3) test area; with values ranging from 0.001-2.016 mWcm-2. To evaluate antibacterial efficacy of the light source for environmental surface decontamination, irradiance levels within this range (0.021-1 mWcm-2) at various angular (Δ ϴ=0-51.3) and linear (∆s=1.6-2.56 m) displacements from the source were used to generate inactivation kinetics, using the model organism, Staphylococcus aureus. Additionally, twelve bacterial species were surface-seeded and light-exposed at a fixed displacement below the source (1.5 m; 0.5 mWcm-2) to demonstrate broad-spectrum efficacy at heights typical of high touch surfaces within occupied settings. Results Results demonstrate that significant (P≤0.05) inactivation was successfully achieved at all irradiance values investigated, with spatial positioning from the source affecting inactivation, with greater times required for inactivation as irradiance decreased. Complete/near-complete (≥93.28%) inactivation of all bacteria was achieved following exposure to 0.5 mWcm-2 within exposure times realistic of those utilised practically for whole-room decontamination (2-16 h). Conclusion This study provides fundamental evidence of the efficacy, and energy efficiency, of low irradiance 405-nm light for bacterial inactivation within a controlled laboratory setting, further justifying its benefits for practical infection control applications.
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Affiliation(s)
- Lucy G Sinclair
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies, Department of Electronic & Electrical Engineering, University of Strathclyde, Glasgow, UK
| | - Laura R Dougall
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies, Department of Electronic & Electrical Engineering, University of Strathclyde, Glasgow, UK
| | - Zornitsa Ilieva
- Department of Biomedical Engineering, University of Strathclyde, Glasgow, UK
| | - Karen McKenzie
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies, Department of Electronic & Electrical Engineering, University of Strathclyde, Glasgow, UK
| | - John G Anderson
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies, Department of Electronic & Electrical Engineering, University of Strathclyde, Glasgow, UK
| | - Scott J MacGregor
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies, Department of Electronic & Electrical Engineering, University of Strathclyde, Glasgow, UK
| | - Michelle Maclean
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies, Department of Electronic & Electrical Engineering, University of Strathclyde, Glasgow, UK
- Department of Biomedical Engineering, University of Strathclyde, Glasgow, UK
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Karczewska M, Strzelecki P, Szalewska-Pałasz A, Nowicki D. How to Tackle Bacteriophages: The Review of Approaches with Mechanistic Insight. Int J Mol Sci 2023; 24:ijms24054447. [PMID: 36901878 PMCID: PMC10003480 DOI: 10.3390/ijms24054447] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 02/21/2023] [Accepted: 02/22/2023] [Indexed: 02/26/2023] Open
Abstract
Bacteriophage-based applications have a renaissance today, increasingly marking their use in industry, medicine, food processing, biotechnology, and more. However, phages are considered resistant to various harsh environmental conditions; besides, they are characterized by high intra-group variability. Phage-related contaminations may therefore pose new challenges in the future due to the wider use of phages in industry and health care. Therefore, in this review, we summarize the current knowledge of bacteriophage disinfection methods, as well as highlight new technologies and approaches. We discuss the need for systematic solutions to improve bacteriophage control, taking into account their structural and environmental diversity.
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Affiliation(s)
- Monika Karczewska
- Department of Bacterial Molecular Genetics, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland
| | - Patryk Strzelecki
- Department of Bacterial Molecular Genetics, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland
- Institut de Physique et Chimie des Matériaux de Strasbourg, Université de Strasbourg, CNRS, UMR7504, 23 rue du Loess, CEDEX 2, F-67034 Strasbourg, France
| | - Agnieszka Szalewska-Pałasz
- Department of Bacterial Molecular Genetics, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland
| | - Dariusz Nowicki
- Department of Bacterial Molecular Genetics, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland
- Correspondence: ; Tel.: +48-58-523-6065
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Zhang W, Su P, Ma J, Gong M, Ma L, Wang J. A singlet state oxygen generation model based on the Monte Carlo method of visible antibacterial blue light inactivation. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2023; 239:112628. [PMID: 36610348 DOI: 10.1016/j.jphotobiol.2022.112628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 11/22/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022]
Abstract
Visible antibacterial blue light (VABL) has received much attention recently as a nondestructive inactivation approach. However, due to the sparse distribution of bacteria, the light energy evaluation method used in existing studies is inaccurate. Thus, the sensitivity of microorganisms to VABL in different experiments cannot be compared. In this paper, a Monte Carlo-based photon transport model with the optimized scattering phase function was constructed. The model calculated the spatial light energy distribution and the temporal distribution of cumulative singlet state oxygen (CSO) under various cell and medium parameters. The simulation results show that when the cells are sparsely distributed, <30% of light energy from the light source is absorbed by microbes and participates in photochemical reactions. The CSO produced increases with cell density and cell size. Little light energy is available, and thus, the concentration of CSO produced is insufficient to inactivate microbes at deeper depths. As the light intensity and inactivation time increased, the production of singlet state oxygen tended to level off. The model proposed here can quantify the generation of singlet state oxygen and provide a more accurate light energy guide for the VABL inactivation process.
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Affiliation(s)
- Wanqing Zhang
- Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
| | - Ping Su
- Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China
| | - Jianshe Ma
- Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China.
| | - Mali Gong
- Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China; Department of Precision Instrument, Tsinghua University, Beijing 100084, China
| | - Liya Ma
- Shenzhen Baoan Women and Children's Hospital, Jinan University, Shenzhen 518100, China
| | - Jing Wang
- College of Water Conservancy, Yunnan Agricultural University, Kunming 650000, China
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7
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Kvam E, Davis B, Benner K. Comparative Assessment of Pulsed and Continuous LED UV-A Lighting for Disinfection of Contaminated Surfaces. Life (Basel) 2022; 12:1747. [PMID: 36362902 PMCID: PMC9696731 DOI: 10.3390/life12111747] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 10/23/2022] [Accepted: 10/29/2022] [Indexed: 08/27/2023] Open
Abstract
The germicidal efficacy of LED UV-A lighting has scarcely been compared in continuous and pulsed modes for contaminated surfaces. Herein, we compare the disinfection properties of pulsed versus continuous lighting at equal irradiances using a 365 nm LED device that replicates the doses of occupied-space continuous disinfection UV-A products. Representative organisms evaluated in this study included human-infectious enveloped and non-enveloped viruses (lentivirus and adeno-associated virus, respectively), a bacterial endospore (Bacillus atrophaeus), and a resilient gram-positive bacterium (Enterococcus faecalis). Nominal UV-A irradiances were tested at or below the UL standard limit for continuous human exposure (maximum irradiance of 10 W/m2). We observed photoinactivation properties that varied by organism type, with bacteria and enveloped virus being more susceptible to UV-A than non-enveloped virus and spores. Overall, we conclude that continuous-mode UV-A lighting is better suited for occupied-space disinfection than pulsing UV-A at equivalent low irradiances, and we draw comparisons to other studies in the literature.
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Affiliation(s)
- Erik Kvam
- GE Research, One Research Circle, K1 5D29, Niskayuna, NY 12309, USA
| | - Brian Davis
- GE Research, One Research Circle, K1 5D29, Niskayuna, NY 12309, USA
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8
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Yu X, Zheng P, Zou Y, Ye Z, Wei T, Lin J, Guo L, Yuk HG, Zheng Q. A review on recent advances in LED-based non-thermal technique for food safety: current applications and future trends. Crit Rev Food Sci Nutr 2022; 63:7692-7707. [PMID: 35369810 DOI: 10.1080/10408398.2022.2049201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Light-emitting diodes (LEDs) is an eco-friendly light source with broad-spectrum antimicrobial activity. Recent studies have extensively been conducted to evaluate its efficacy in microbiological safety and the potential as a preservation method to extend the shelf-life of foods. This review aims to present the latest update of recent studies on the basics (physical, biochemical and mechanical basics) and antimicrobial activity of LEDs, as well as its application in the food industry. The highlight will be focused on the effects of LEDs on different types (bacteria, yeast/molds, viruses) and forms (planktonic cells, biofilms, endospores, fungal toxin) of microorganisms. The antimicrobial activity of LEDs on various food matrices was also evaluated, together with further analysis on the food-related factors that lead to the differences in LEDs efficiency. Besides, the applications of LEDs on the food-related conditions, packaged food, and equipment that could enhance LEDs efficiency were discussed to explore the future trends of LEDs technology in the food industry. Overall, the present review provides important insights for future research and the application of LEDs in the food industry.
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Affiliation(s)
- Xinpeng Yu
- College of Food Science & Institute of Food Biotechnology, South China Agricultural University, Guangzhou, China
- Research Center for Micro-Ecological Agent Engineering and Technology of Guangdong Province, Guangzhou, China
| | - Peng Zheng
- College of Horticulture, South China Agricultural University, Guangzhou, China
| | - Yuan Zou
- College of Food Science & Institute of Food Biotechnology, South China Agricultural University, Guangzhou, China
- Research Center for Micro-Ecological Agent Engineering and Technology of Guangdong Province, Guangzhou, China
| | - Zhiwei Ye
- College of Food Science & Institute of Food Biotechnology, South China Agricultural University, Guangzhou, China
- Research Center for Micro-Ecological Agent Engineering and Technology of Guangdong Province, Guangzhou, China
| | - Tao Wei
- College of Food Science & Institute of Food Biotechnology, South China Agricultural University, Guangzhou, China
- Research Center for Micro-Ecological Agent Engineering and Technology of Guangdong Province, Guangzhou, China
| | - Junfang Lin
- College of Food Science & Institute of Food Biotechnology, South China Agricultural University, Guangzhou, China
- Research Center for Micro-Ecological Agent Engineering and Technology of Guangdong Province, Guangzhou, China
| | - Liqiong Guo
- College of Food Science & Institute of Food Biotechnology, South China Agricultural University, Guangzhou, China
- Research Center for Micro-Ecological Agent Engineering and Technology of Guangdong Province, Guangzhou, China
| | - Hyun-Gyun Yuk
- Department of Food Science and Technology, Korea National University of Transportation, Chungbuk, Republic of Korea
| | - Qianwang Zheng
- College of Food Science & Institute of Food Biotechnology, South China Agricultural University, Guangzhou, China
- Research Center for Micro-Ecological Agent Engineering and Technology of Guangdong Province, Guangzhou, China
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Abstract
The COVID-19 pandemic is driving the search for new antiviral techniques. Bacteria and fungi are known to be inactivated not only by ultraviolet radiation but also by visible light. Several studies have recently appeared on this subject, in which viruses were mainly irradiated in media. However, it is an open question to what extent the applied media, and especially their riboflavin concentration, can influence the results. A literature search identified appropriate virus photoinactivation publications and, where possible, viral light susceptibility was quantitatively determined in terms of average log-reduction doses. Sensitivities of enveloped viruses were plotted against assumed riboflavin concentrations. Viruses appear to be sensitive to visible (violet/blue) light. The median log-reduction doses of all virus experiments performed in liquids is 58 J/cm2. For the non-enveloped, enveloped and coronaviruses only, they were 222, 29 and 19 J/cm2, respectively. Data are scarce, but it appears that (among other things) the riboflavin concentration in the medium has an influence on the log-reduction doses. Experiments with DMEM, with its 0.4 mg/L riboflavin, have so far produced results with the greatest viral susceptibilities. It should be critically evaluated whether the currently published virus sensitivities are really only intrinsic properties of the virus, or whether the medium played a significant role. In future experiments, irradiation should be carried out in solutions with the lowest possible riboflavin concentration.
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Terrosi C, Anichini G, Docquier JD, Gori Savellini G, Gandolfo C, Pavone FS, Cusi MG. Efficient Inactivation of SARS-CoV-2 and Other RNA or DNA Viruses with Blue LED Light. Pathogens 2021; 10:pathogens10121590. [PMID: 34959545 PMCID: PMC8708627 DOI: 10.3390/pathogens10121590] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 11/16/2021] [Accepted: 12/06/2021] [Indexed: 11/16/2022] Open
Abstract
Blue LED light has proven to have a powerful bacteria-killing ability; however, little is known about its mechanism of virucidal activity. Therefore, we analyzed the effect of blue light on different respiratory viruses, such as adenovirus, respiratory syncytial virus and SARS-CoV-2. The exposure of samples to a blue LED light with a wavelength of 420 nm (i.e., in the visible range) at 20 mW/cm2 of irradiance for 15 min appeared optimal and resulted in the complete inactivation of the viral load. These results were similar for all the three viruses, demonstrating that both enveloped and naked viruses could be efficiently inactivated with blue LED light, regardless of the presence of envelope and of the viral genome nature (DNA or RNA). Moreover, we provided some explanations to the mechanisms by which the blue LED light could exert its antiviral activity. The development of such safe and low-cost light-based devices appears to be of fundamental utility for limiting viral spread and for sanitizing small environments, objects and surfaces, especially in the pandemic era.
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Affiliation(s)
- Chiara Terrosi
- Department of Medical Biotechnologies, University of Siena, 53100 Siena, Italy; (C.T.); (G.A.); (J.D.D.); (G.G.S.); (C.G.)
| | - Gabriele Anichini
- Department of Medical Biotechnologies, University of Siena, 53100 Siena, Italy; (C.T.); (G.A.); (J.D.D.); (G.G.S.); (C.G.)
| | - Jean Denis Docquier
- Department of Medical Biotechnologies, University of Siena, 53100 Siena, Italy; (C.T.); (G.A.); (J.D.D.); (G.G.S.); (C.G.)
| | - Gianni Gori Savellini
- Department of Medical Biotechnologies, University of Siena, 53100 Siena, Italy; (C.T.); (G.A.); (J.D.D.); (G.G.S.); (C.G.)
| | - Claudia Gandolfo
- Department of Medical Biotechnologies, University of Siena, 53100 Siena, Italy; (C.T.); (G.A.); (J.D.D.); (G.G.S.); (C.G.)
| | - Francesco Saverio Pavone
- Department of Physics and Astronomy, European Laboratory for Non Linear Spectroscopy (LENS), University of Florence, 50121 Florence, Italy;
| | - Maria Grazia Cusi
- Department of Medical Biotechnologies, University of Siena, 53100 Siena, Italy; (C.T.); (G.A.); (J.D.D.); (G.G.S.); (C.G.)
- Correspondence: ; Tel.: +39-0577-233871; Fax: +39-0577-233870
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11
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Rathnasinghe R, Jangra S, Miorin L, Schotsaert M, Yahnke C, Garcίa-Sastre A. The virucidal effects of 405 nm visible light on SARS-CoV-2 and influenza A virus. Sci Rep 2021; 11:19470. [PMID: 34593848 PMCID: PMC8484654 DOI: 10.1038/s41598-021-97797-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 08/26/2021] [Indexed: 12/23/2022] Open
Abstract
The germicidal potential of specific wavelengths within the electromagnetic spectrum is an area of growing interest. While ultra-violet (UV) based technologies have shown satisfactory virucidal potential, the photo-toxicity in humans coupled with UV associated polymer degradation limit their use in occupied spaces. Alternatively, longer wavelengths with less irradiation energy such as visible light (405 nm) have largely been explored in the context of bactericidal and fungicidal applications. Such studies indicated that 405 nm mediated inactivation is caused by the absorbance of porphyrins within the organism creating reactive oxygen species which result in free radical damage to its DNA and disruption of cellular functions. The virucidal potential of visible-light based technologies has been largely unexplored and speculated to be ineffective given the lack of porphyrins in viruses. The current study demonstrated increased susceptibility of lipid-enveloped respiratory pathogens of importance such as SARS-CoV-2 (causative agent of COVID-19) and influenza A virus to 405 nm, visible light in the absence of exogenous photosensitizers thereby indicating a potential alternative porphyrin-independent mechanism of visible light mediated viral inactivation. These results were obtained using less than expected irradiance levels which are considered safe for humans and commercially achievable. Our results support further exploration of the use of visible light technology for the application of continuous decontamination in occupied areas within hospitals and/or infectious disease laboratories, specifically for the inactivation of respiratory pathogens such as SARS-CoV-2 and Influenza A.
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Affiliation(s)
- Raveen Rathnasinghe
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Sonia Jangra
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Lisa Miorin
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Michael Schotsaert
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | | | - Adolfo Garcίa-Sastre
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
- Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
- Division of Infectious Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
- The Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
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Schlachter A, Asselin P, Harvey PD. Porphyrin-Containing MOFs and COFs as Heterogeneous Photosensitizers for Singlet Oxygen-Based Antimicrobial Nanodevices. ACS APPLIED MATERIALS & INTERFACES 2021; 13:26651-26672. [PMID: 34086450 DOI: 10.1021/acsami.1c05234] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Visible-light irradiation of porphyrin and metalloporphyrin dyes in the presence of molecular oxygen can result in the photocatalytic generation of singlet oxygen (1O2). This type II reactive oxygen species (ROS) finds many applications where the dye, also called the photosensitizer, is dissolved (i.e., homogeneous phase) along with the substrate to be oxidized. In contrast, metal-organic frameworks (MOFs) are insoluble (or will disassemble) when placed in a solvent. When stable as a suspension, MOFs adsorb a large amount of O2 and photocatalytically generate 1O2 in a heterogeneous process efficiently. Considering the immense surface area and great capacity for gas adsorption of MOFs, they seem ideal candidates for this application. Very recently, covalent-organic frameworks (COFs), variants where reticulation relies on covalent rather than coordination bonds, have emerged as efficient photosensitizers. This comprehensive mini review describes recent developments in the use of porphyrin-based or porphyrin-containing MOFs and COFs, including nanosized versions, as heterogeneous photosensitizers of singlet oxygen toward antimicrobial applications.
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Affiliation(s)
- Adrien Schlachter
- Département de Chimie, Université de Sherbrooke, Sherbrooke, Quebec J1K 2R1, Canada
| | - Paul Asselin
- Département de Chimie, Université de Sherbrooke, Sherbrooke, Quebec J1K 2R1, Canada
| | - Pierre D Harvey
- Département de Chimie, Université de Sherbrooke, Sherbrooke, Quebec J1K 2R1, Canada
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13
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Vatter P, Hoenes K, Hessling M. Blue light inactivation of the enveloped RNA virus Phi6. BMC Res Notes 2021; 14:187. [PMID: 34001258 PMCID: PMC8128082 DOI: 10.1186/s13104-021-05602-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 05/06/2021] [Indexed: 11/10/2022] Open
Abstract
OBJECTIVE Ultraviolet radiation is known for its antimicrobial properties but unfortunately, it could also harm humans. Currently, disinfection techniques against SARS-CoV-2 are being sought that can be applied on air and surfaces and which do not pose a relevant thread to humans. In this study, the bacteriophage phi6, which like SARS-CoV-2 is an enveloped RNA virus, is irradiated with visible blue light at a wavelength of 455 nm. RESULTS For the first time worldwide, the antiviral properties of blue light around 455 nm can be demonstrated. With a dose of 7200 J/cm2, the concentration of this enveloped RNA virus can be successfully reduced by more than three orders of magnitude. The inactivation mechanism is still unknown, but the sensitivity ratio of phi6 towards blue and violet light hints towards an involvement of photosensitizers of the host cells. Own studies on coronaviruses cannot be executed, but the results support speculations about blue-susceptibility of coronaviruses, which might allow to employ blue light for infection prevention or even therapeutic applications.
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Affiliation(s)
- Petra Vatter
- Institute of Medical Engineering and Mechatronics, Ulm University of Applied Sciences, Ulm, Germany
| | - Katharina Hoenes
- Institute of Medical Engineering and Mechatronics, Ulm University of Applied Sciences, Ulm, Germany
| | - Martin Hessling
- Institute of Medical Engineering and Mechatronics, Ulm University of Applied Sciences, Ulm, Germany
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14
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Ahmed H, Maunula L, Korhonen J. Reduction of Norovirus in Foods by Nonthermal Treatments: A Review. J Food Prot 2020; 83:2053-2073. [PMID: 32649759 DOI: 10.4315/jfp-20-177] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 07/10/2020] [Indexed: 12/19/2022]
Abstract
ABSTRACT Human noroviruses are enteric pathogens that cause a substantial proportion of acute gastroenteritis cases worldwide regardless of background variables such as age, ethnicity, and gender. Although person-to-person contact is the general route of transmission, foodborne infections are also common. Thorough cooking eliminates noroviruses, but several food products such as berries, leafy vegetables, and mollusks undergo only limited heat treatment, if any, before consumption. Novel applications of nonthermal processing technologies are currently being vigorously researched because they can be used to inactivate pathogens and extend product shelf life with limited effects on nutrient content and perceived quality. These technologies, adopted from several industrial fields, include some methods already approved for food processing that have been applied in the food industry for years. However, a majority of the research has been conducted with bacteria and simple matrixes or surfaces. This review focuses on elimination of norovirus in food matrixes by use of nonthermal technologies in four categories: high hydrostatic pressure, light, irradiation, and cold atmospheric plasma. We discuss the properties of noroviruses, principles and inactivation mechanisms of select technologies, and main findings of relevant studies. We also provide an overview of the current status of the research and propose future directions for related work. HIGHLIGHTS
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Affiliation(s)
- Hany Ahmed
- Institute of Public Health and Clinical Nutrition, University of Eastern Finland, 70211 Kuopio, Finland.,(ORCID: https://orcid.org/0000-0002-5876-3970 [H.A.])
| | - Leena Maunula
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, 00014 Helsinki, Finland (ORCID: https://orcid.org/0000-0002-0841-5353 [L.M.])
| | - Jenni Korhonen
- Institute of Public Health and Clinical Nutrition, University of Eastern Finland, 70211 Kuopio, Finland
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15
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Vatter P, Hoenes K, Hessling M. Photoinactivation of the Coronavirus Surrogate phi6 by Visible Light. Photochem Photobiol 2020; 97:122-125. [PMID: 33128245 DOI: 10.1111/php.13352] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 10/07/2020] [Accepted: 10/26/2020] [Indexed: 12/15/2022]
Abstract
To stop the coronavirus spread, new inactivation approaches are being sought that can also be applied in the presence of humans or even on humans. Here, we investigate the effect of visible violet light with a wavelength of 405 nm on the coronavirus surrogate phi6 in two aqueous solutions that are free of photosensitizers. A dose of 1300 J cm-2 of 405 nm irradiation reduces the phi6 plaque-forming unit concentration by three log-levels. The next step should be similar visible light photoinactivation investigations on coronaviruses, which cannot be performed in our lab.
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Affiliation(s)
- Petra Vatter
- Ulm University of Applied Sciences, Ulm, Germany
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16
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Sabino CP, Ball AR, Baptista MS, Dai T, Hamblin MR, Ribeiro MS, Santos AL, Sellera FP, Tegos GP, Wainwright M. Light-based technologies for management of COVID-19 pandemic crisis. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2020; 212:111999. [PMID: 32855026 PMCID: PMC7435279 DOI: 10.1016/j.jphotobiol.2020.111999] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 08/07/2020] [Accepted: 08/17/2020] [Indexed: 12/17/2022]
Abstract
The global dissemination of the novel coronavirus disease (COVID-19) has accelerated the need for the implementation of effective antimicrobial strategies to target the causative agent SARS-CoV-2. Light-based technologies have a demonstrable broad range of activity over standard chemotherapeutic antimicrobials and conventional disinfectants, negligible emergence of resistance, and the capability to modulate the host immune response. This perspective article identifies the benefits, challenges, and pitfalls of repurposing light-based strategies to combat the emergence of COVID-19 pandemic.
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Affiliation(s)
- Caetano P Sabino
- Department of Clinical Analysis, Faculty of Pharmaceutical Sciences, University of São Paulo, SP, Brazil; BioLambda, Scientific and Commercial LTD, São Paulo, SP, Brazil.
| | - Anthony R Ball
- GAMA Therapeutics LLC, Massachusetts Biomedical Initiatives, Worcester, USA
| | - Mauricio S Baptista
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, SP, Brazil..
| | - Tianhong Dai
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; Vaccine and Immunotherapy Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Michael R Hamblin
- Wellman Center for Photomedicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; Laser Research Centre, Faculty of Health Science, University of Johannesburg, Doornfontein, South Africa
| | - Martha S Ribeiro
- Center for Lasers and Applications, Nuclear, and Energy Research Institute, National Commission for Nuclear Energy, São Paulo, SP, Brazil
| | - Ana L Santos
- GAMA Therapeutics LLC, Massachusetts Biomedical Initiatives, Worcester, USA; Department of Chemistry Rice University, Houston, TX, USA; IdISBA - Fundación de Investigación Sanitaria de las Islas Baleares, Palma, Spain
| | - Fábio P Sellera
- Department of Internal Medicine, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, SP, Brazil; School of Veterinary Medicine, Metropolitan University of Santos, Santos, Brazil
| | - George P Tegos
- GAMA Therapeutics LLC, Massachusetts Biomedical Initiatives, Worcester, USA; Micromoria LLC, Marlborough, USA
| | - Mark Wainwright
- School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool, UK
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17
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Hadi J, Dunowska M, Wu S, Brightwell G. Control Measures for SARS-CoV-2: A Review on Light-Based Inactivation of Single-Stranded RNA Viruses. Pathogens 2020; 9:E737. [PMID: 32911671 PMCID: PMC7558314 DOI: 10.3390/pathogens9090737] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 09/04/2020] [Accepted: 09/05/2020] [Indexed: 12/20/2022] Open
Abstract
SARS-CoV-2 is a single-stranded RNA virus classified in the family Coronaviridae. In this review, we summarize the literature on light-based (UV, blue, and red lights) sanitization methods for the inactivation of ssRNA viruses in different matrixes (air, liquid, and solid). The rate of inactivation of ssRNA viruses in liquid was higher than in air, whereas inactivation on solid surfaces varied with the type of surface. The efficacy of light-based inactivation was reduced by the presence of absorptive materials. Several technologies can be used to deliver light, including mercury lamp (conventional UV), excimer lamp (UV), pulsed-light, and light-emitting diode (LED). Pulsed-light technologies could inactivate viruses more quickly than conventional UV-C lamps. Large-scale use of germicidal LED is dependent on future improvements in their energy efficiency. Blue light possesses virucidal potential in the presence of exogenous photosensitizers, although femtosecond laser (ultrashort pulses) can be used to circumvent the need for photosensitizers. Red light can be combined with methylene blue for application in medical settings, especially for sanitization of blood products. Future modelling studies are required to establish clearer parameters for assessing susceptibility of viruses to light-based inactivation. There is considerable scope for improvement in the current germicidal light-based technologies and practices.
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Affiliation(s)
- Joshua Hadi
- AgResearch Ltd., Hopkirk Research Institute, Cnr University Ave and Library Road, Massey University, Palmerston North 4442, New Zealand; (J.H.); (S.W.)
| | - Magdalena Dunowska
- School of Veterinary Science, Massey University Manawatu (Turitea) Tennent Drive, Palmerston North 4474, New Zealand;
| | - Shuyan Wu
- AgResearch Ltd., Hopkirk Research Institute, Cnr University Ave and Library Road, Massey University, Palmerston North 4442, New Zealand; (J.H.); (S.W.)
| | - Gale Brightwell
- AgResearch Ltd., Hopkirk Research Institute, Cnr University Ave and Library Road, Massey University, Palmerston North 4442, New Zealand; (J.H.); (S.W.)
- New Zealand Food Safety Science and Research Centre, Massey University Manawatu (Turitea) Tennent Drive, Palmerston North 4474, New Zealand
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18
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Enhancement of Contact Lens Disinfection by Combining Disinfectant with Visible Light Irradiation. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17176422. [PMID: 32899295 PMCID: PMC7504152 DOI: 10.3390/ijerph17176422] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 08/28/2020] [Accepted: 08/29/2020] [Indexed: 01/05/2023]
Abstract
Multiple use contact lenses have to be disinfected overnight to reduce the risk of infections. However, several studies demonstrated that not only microorganisms are affected by the disinfectants, but also ocular epithelial cells, which come into contact via residuals at reinsertion of the lens. Visible light has been demonstrated to achieve an inactivation effect on several bacterial and fungal species. Combinations with other disinfection methods often showed better results compared to separately applied methods. We therefore investigated contact lens disinfection solutions combined with 405 nm irradiation, with the intention to reduce the disinfectant concentration of ReNu Multiplus, OptiFree Express or AOSept while maintaining adequate disinfection results due to combination benefits. Pseudomonads, staphylococci and E. coli were studied with disk diffusion assay, colony forming unit (cfu) determination and growth delay. A log reduction of 4.49 was achieved for P. fluorescens in 2 h for 40% ReNu Multiplus combined with an irradiation intensity of 20 mW/cm2 at 405 nm. For AOSept the combination effect was so strong that 5% of AOSept in combination with light exhibited the same result as 100% AOSept alone. Combination of disinfectants with visible violet light is therefore considered a promising approach, as a reduction of potentially toxic ingredients can be achieved.
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19
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Kvam E, Benner K. Mechanistic insights into UV-A mediated bacterial disinfection via endogenous photosensitizers. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2020; 209:111899. [PMID: 32485344 DOI: 10.1016/j.jphotobiol.2020.111899] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 05/13/2020] [Accepted: 05/15/2020] [Indexed: 01/09/2023]
Abstract
UV-A and visible light are thought to excite endogenous photosensitizers in microbes, thereby initiating complex chemical interactions that ultimately kill cells. Natural solar-based disinfection methods have been adapted into commercial lighting technologies with varying degrees of reported efficacy and associated safety hazards for human exposure. Here we utilize a narrow-spectrum UV-A LED prototype (currently in development for health care applications) to investigate the mechanism of bacterial photoinactivation using 365 nm light. Using a combination of reverse genetics and biochemical investigation, we report mechanistic evidence that 365nm light initiates a chain-reaction of superoxide-mediated damage via auto-excitation of vitamin-based electron carriers, specifically vitamin K2 menaquinones and the FAD flavoprotein in Complex II in the electron transport chain. We observe that photoinactivation is modifiable through supplementation of the environment to bypass cell damage. Lastly, we observe that bacteria forced into metabolic dormancy by desiccation become hypersensitized to the effects of UV-A light, thereby permitting photoinactivation at fluences that are significantly lower than the industry threshold for safe human exposure. In total, these results substantiate the mechanism and potential application of narrow- spectrum UV-A light for bacterial disinfection purposes.
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Affiliation(s)
- Erik Kvam
- GE Research, One Research Circle, Niskayuna, NY 12309, USA.
| | - Kevin Benner
- GE Current, a Daintree Company, East Cleveland, OH 44112, USA
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20
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Horton L, Torres AE, Narla S, Lyons AB, Kohli I, Gelfand JM, Ozog DM, Hamzavi IH, Lim HW. Spectrum of virucidal activity from ultraviolet to infrared radiation. Photochem Photobiol Sci 2020; 19:1262-1270. [PMID: 32812619 PMCID: PMC8047562 DOI: 10.1039/d0pp00221f] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The COVID-19 pandemic has sparked a demand for safe and highly effective decontamination techniques for both personal protective equipment (PPE) and hospital and operating rooms. The gradual lifting of lockdown restrictions warrants the expansion of these measures into the outpatient arena. Ultraviolet C (UVC) radiation has well-known germicidal properties and is among the most frequently reported decontamination techniques used today. However, there is evidence that wavelengths beyond the traditional 254 nm UVC - namely far UVC (222 nm), ultraviolet B, ultraviolet A, visible light, and infrared radiation - have germicidal properties as well. This review will cover current literature regarding the germicidal effects of wavelengths ranging from UVC through the infrared waveband with an emphasis on their activity against viruses, and their potential applicability in the healthcare setting for general decontamination during an infectious outbreak.
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Affiliation(s)
- Luke Horton
- Wayne State University School of Medicine, Detroit, MI USA
| | - Angeli Eloise Torres
- Photomedicine and Photobiology Unit, Department of Dermatology, Henry Ford Health System, Detroit, MI USA
| | - Shanthi Narla
- Photomedicine and Photobiology Unit, Department of Dermatology, Henry Ford Health System, Detroit, MI USA
| | - Alexis B. Lyons
- Photomedicine and Photobiology Unit, Department of Dermatology, Henry Ford Health System, Detroit, MI USA
| | - Indermeet Kohli
- Photomedicine and Photobiology Unit, Department of Dermatology, Henry Ford Health System, Detroit, MI USA ,Department of Physics and Astronomy, Wayne State University, Detroit, MI USA
| | - Joel M. Gelfand
- Department of Dermatology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA USA
| | - David M. Ozog
- Photomedicine and Photobiology Unit, Department of Dermatology, Henry Ford Health System, Detroit, MI USA
| | - Iltefat H. Hamzavi
- Photomedicine and Photobiology Unit, Department of Dermatology, Henry Ford Health System, Detroit, MI USA
| | - Henry W. Lim
- Photomedicine and Photobiology Unit, Department of Dermatology, Henry Ford Health System, Detroit, MI USA
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21
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Tomb RM, White TA, Coia JE, Anderson JG, MacGregor SJ, Maclean M. Review of the Comparative Susceptibility of Microbial Species to Photoinactivation Using 380-480 nm Violet-Blue Light. Photochem Photobiol 2018; 94:445-458. [DOI: 10.1111/php.12883] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 12/08/2017] [Indexed: 12/24/2022]
Affiliation(s)
- Rachael M. Tomb
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST); Department of Electronic & Electrical Engineering; University of Strathclyde; Glasgow UK
| | - Tracy A. White
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST); Department of Electronic & Electrical Engineering; University of Strathclyde; Glasgow UK
| | - John E. Coia
- Department of Clinical Microbiology; Glasgow Royal Infirmary; Glasgow UK
| | - John G. Anderson
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST); Department of Electronic & Electrical Engineering; University of Strathclyde; Glasgow UK
| | - Scott J. MacGregor
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST); Department of Electronic & Electrical Engineering; University of Strathclyde; Glasgow UK
| | - Michelle Maclean
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST); Department of Electronic & Electrical Engineering; University of Strathclyde; Glasgow UK
- Department of Biomedical Engineering; University of Strathclyde; Glasgow UK
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22
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Tomb RM, Maclean M, Coia JE, MacGregor SJ, Anderson JG. Assessment of the potential for resistance to antimicrobial violet-blue light in Staphylococcus aureus. Antimicrob Resist Infect Control 2017; 6:100. [PMID: 29046782 PMCID: PMC5639585 DOI: 10.1186/s13756-017-0261-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 09/18/2017] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND Antimicrobial violet-blue light in the region of 405 nm is emerging as an alternative technology for hospital decontamination and clinical treatment. The mechanism of action is the excitation of endogenous porphyrins within exposed microorganisms, resulting in ROS generation, oxidative damage and cell death. Although resistance to 405 nm light is not thought likely, little evidence has been published to support this. This study was designed to establish if there is potential for tolerance development, using the nosocomial pathogen Staphylococcus aureus as the model organism. METHODS The first stage of this study investigated the potential for S. aureus to develop tolerance to high-intensity 405 nm light if pre-cultured in low-level stress violet-blue light (≤1 mW/cm2) conditions. Secondly, the potential for tolerance development in bacteria subjected to repeated sub-lethal exposure was compared by carrying out 15 cycles of exposure to high-intensity 405 nm light, using a sub-lethal dose of 108 J/cm2. Inactivation kinetics and antibiotic susceptibility were also compared. RESULTS When cultured in low-level violet-blue light conditions, S. aureus required a greater dose of high-intensity 405 nm light for complete inactivation, however this did not increase with multiple (3) low-stress cultivations. Repeated sub-lethal exposures indicated no evidence of bacterial tolerance to 405 nm light. After 15 sub-lethal exposures 1.2 and 1.4 log10 reductions were achieved for MSSA and MRSA respectively, which were not significantly different to the initial 1.3 log10 reductions achieved (P = 0.242 & 0.116, respectively). Antibiotic susceptibility was unaffected, with the maximum change in zone of inhibition being ± 2 mm. CONCLUSIONS Repeated sub-lethal exposure of non-proliferating S. aureus populations did not affect the susceptibility of the organism to 405 nm light, nor to antibiotics. Culture in low-level violet-blue light prior to 405 nm light exposure may increase oxidative stress responses in S. aureus, however, inactivation still occurs and results demonstrate that this is unlikely to be a selective process. These results demonstrate that tolerance from repeated exposure is unlikely to occur, and further supports the potential development of 405 nm light for clinical decontamination and treatment applications.
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Affiliation(s)
- Rachael M Tomb
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST), Department of Electronic & Electrical Engineering, University of Strathclyde, Glasgow, UK
| | - Michelle Maclean
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST), Department of Electronic & Electrical Engineering, University of Strathclyde, Glasgow, UK.,Department of Biomedical Engineering, University of Strathclyde, Glasgow, UK
| | - John E Coia
- Department of Clinical Microbiology, Glasgow Royal Infirmary, Glasgow, UK
| | - Scott J MacGregor
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST), Department of Electronic & Electrical Engineering, University of Strathclyde, Glasgow, UK
| | - John G Anderson
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST), Department of Electronic & Electrical Engineering, University of Strathclyde, Glasgow, UK
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23
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Tomb RM, Maclean M, Coia JE, Graham E, McDonald M, Atreya CD, MacGregor SJ, Anderson JG. New Proof-of-Concept in Viral Inactivation: Virucidal Efficacy of 405 nm Light Against Feline Calicivirus as a Model for Norovirus Decontamination. FOOD AND ENVIRONMENTAL VIROLOGY 2017; 9:159-167. [PMID: 28040848 PMCID: PMC5429381 DOI: 10.1007/s12560-016-9275-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Accepted: 12/10/2016] [Indexed: 06/01/2023]
Abstract
The requirement for novel decontamination technologies for use in hospitals is ever present. One such system uses 405 nm visible light to inactivate microorganisms via ROS-generated oxidative damage. Although effective for bacterial and fungal inactivation, little is known about the virucidal effects of 405 nm light. Norovirus (NoV) gastroenteritis outbreaks often occur in the clinical setting, and this study was designed to investigate potential inactivation effects of 405 nm light on the NoV surrogate, feline calicivirus (FCV). FCV was exposed to 405 nm light whilst suspended in minimal and organically-rich media to establish the virucidal efficacy and the effect biologically-relevant material may play in viral susceptibility. Antiviral activity was successfully demonstrated with a 4 Log10 (99.99%) reduction in infectivity when suspended in minimal media evident after a dose of 2.8 kJ cm-2. FCV exposed in artificial faeces, artificial saliva, blood plasma and other organically rich media exhibited an equivalent level of inactivation using between 50-85% less dose of the light, indicating enhanced inactivation when the virus is present in organically-rich biologically-relevant media. Further research in this area could aid in the development of 405 nm light technology for effective NoV decontamination within the hospital environment.
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Affiliation(s)
- Rachael M Tomb
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST), Department of Electronic & Electrical Engineering, University of Strathclyde, Royal College Building, 204 George Street, Glasgow, G1 1XW, Scotland, UK.
| | - Michelle Maclean
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST), Department of Electronic & Electrical Engineering, University of Strathclyde, Royal College Building, 204 George Street, Glasgow, G1 1XW, Scotland, UK
- Department of Biomedical Engineering, University of Strathclyde, Wolfson Centre, 106 Rottenrow, Glasgow, Scotland, UK
| | - John E Coia
- Department of Clinical Microbiology, Glasgow Royal Infirmary, Glasgow, Scotland, UK
| | - Elizabeth Graham
- School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, UK
| | - Michael McDonald
- School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, UK
| | - Chintamani D Atreya
- Office of Blood Research and Review, Center for Biologics Evaluation and Research, Food and Drug Administration, Bethesda, MD, USA
| | - Scott J MacGregor
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST), Department of Electronic & Electrical Engineering, University of Strathclyde, Royal College Building, 204 George Street, Glasgow, G1 1XW, Scotland, UK
| | - John G Anderson
- The Robertson Trust Laboratory for Electronic Sterilisation Technologies (ROLEST), Department of Electronic & Electrical Engineering, University of Strathclyde, Royal College Building, 204 George Street, Glasgow, G1 1XW, Scotland, UK
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24
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Gillespie JB, Maclean M, Given MJ, Wilson MP, Judd MD, Timoshkin IV, MacGregor SJ. Efficacy of Pulsed 405-nm Light-Emitting Diodes for Antimicrobial Photodynamic Inactivation: Effects of Intensity, Frequency, and Duty Cycle. Photomed Laser Surg 2016; 35:150-156. [PMID: 27759498 PMCID: PMC5346950 DOI: 10.1089/pho.2016.4179] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Objective: This study investigates possible advantages in pulsed over continuous 405-nm light-emitting diode (LED) light for bacterial inactivation and energy efficiency. Background: Alternative nonantibiotic methods of disinfection and infection control have become of significant interest. Recent studies have demonstrated the application of systems using 405-nm LEDs for continuous disinfection of the clinical environment, and also for potential treatment of contaminated wounds. Methods: Liquid suspensions of 103 colony-forming units/mL populations of Staphylococcus aureus were subject to pulsed 405-nm light of different frequencies, duty cycles, and intensities and for different lengths of time. Results: Pulsed exposures with the same average irradiance of 16 mW/cm2 and varying duty cycle (25%, 50%, 75%) showed very similar performance compared with continuous exposures, with 95–98% reduction of S. aureus achieved for all duty cycles. The pulsing frequency was varied in intervals from 100 Hz to 10 kHz and appeared to have little effect on antimicrobial efficacy. However, when comparing pulsed with continuous exposure, an improvement in inactivation per unit optical energy was achieved, with results showing an increase of approximately 83% in optical efficiency. Conclusions: These results suggest that under pulsed conditions, a lower energy consumption and lower perceived brightness could be achieved, thus potentially providing improved operating conditions for medical/infection control applications without compromising antimicrobial efficacy.
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Affiliation(s)
- Jonathan B Gillespie
- 1 Department of Electronic & Electrical Engineering, The Robertson Trust Laboratory for Electronic Sterilisation Technologies, University of Strathclyde , Glasgow, Scotland, United Kingdom
| | - Michelle Maclean
- 1 Department of Electronic & Electrical Engineering, The Robertson Trust Laboratory for Electronic Sterilisation Technologies, University of Strathclyde , Glasgow, Scotland, United Kingdom .,2 Department of Biomedical Engineering, The Robertson Trust Laboratory for Electronic Sterilisation Technologies, University of Strathclyde , Glasgow, Scotland, United Kingdom
| | - Martin J Given
- 3 Department of Electronic & Electrical Engineering, High Voltage Technologies, University of Strathclyde , Glasgow, Scotland, United Kingdom
| | - Mark P Wilson
- 3 Department of Electronic & Electrical Engineering, High Voltage Technologies, University of Strathclyde , Glasgow, Scotland, United Kingdom
| | - Martin D Judd
- 3 Department of Electronic & Electrical Engineering, High Voltage Technologies, University of Strathclyde , Glasgow, Scotland, United Kingdom
| | - Igor V Timoshkin
- 1 Department of Electronic & Electrical Engineering, The Robertson Trust Laboratory for Electronic Sterilisation Technologies, University of Strathclyde , Glasgow, Scotland, United Kingdom .,3 Department of Electronic & Electrical Engineering, High Voltage Technologies, University of Strathclyde , Glasgow, Scotland, United Kingdom
| | - Scott J MacGregor
- 1 Department of Electronic & Electrical Engineering, The Robertson Trust Laboratory for Electronic Sterilisation Technologies, University of Strathclyde , Glasgow, Scotland, United Kingdom .,3 Department of Electronic & Electrical Engineering, High Voltage Technologies, University of Strathclyde , Glasgow, Scotland, United Kingdom
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Synergistic efficacy of 405 nm light and chlorinated disinfectants for the enhanced decontamination of Clostridium difficile spores. Anaerobe 2015; 37:72-7. [PMID: 26708703 DOI: 10.1016/j.anaerobe.2015.12.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 12/13/2015] [Indexed: 01/05/2023]
Abstract
The ability of Clostridium difficile to form highly resilient spores which can survive in the environment for prolonged periods causes major contamination problems. Antimicrobial 405 nm light is being developed for environmental decontamination within hospitals, however further information relating to its sporicidal efficacy is required. This study aims to establish the efficacy of 405 nm light for inactivation of C. difficile vegetative cells and spores, and to establish whether spore susceptibility can be enhanced by the combined use of 405 nm light with low concentration chlorinated disinfectants. Vegetative cells and spore suspensions were exposed to increasing doses of 405 nm light (at 70-225 mW/cm(2)) to establish sensitivity. A 99.9% reduction in vegetative cell population was demonstrated with a dose of 252 J/cm(2), however spores demonstrated higher resilience, with a 10-fold increase in required dose. Exposures were repeated with spores suspended in the hospital disinfectants sodium hypochlorite, Actichlor and Tristel at non-lethal concentrations (0.1%, 0.001% and 0.0001%, respectively). Enhanced sporicidal activity was achieved when spores were exposed to 405 nm light in the presence of the disinfectants, with a 99.9% reduction achieved following exposure to 33% less light dose than required when exposed to 405 nm light alone. In conclusion, C. difficile vegetative cells and spores can be successfully inactivated using 405 nm light, the sporicidal efficacy can be significantly enhanced when exposed in the presence of low concentration chlorinated disinfectants. Further research may lead to the potential use of 405 nm light decontamination in combination with selected hospital disinfectants to enhance C. difficile cleaning and infection control procedures.
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Decontamination of the Hospital Environment: New Technologies for Infection Control. CURRENT TREATMENT OPTIONS IN INFECTIOUS DISEASES 2015. [DOI: 10.1007/s40506-015-0037-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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