Related Experiment Video
Updated: Aug 21, 2026
Inactivation of Pathogens via Visible-Light Photolysis of Riboflavin-5′-Phosphate
Published on: April 6, 2022
Inactivation of dengue virus by methylene blue/narrow bandwidth light system
Qing Huang1, Wei-Ling Fu, Bing Chen
1Department of Laboratory Medicine, Southwestern Hospital, The Third Military Medical University, Chongqing, 400038, PR China. qhuang@mail.com
Abstract:
Peracetic acid was one of the most commonly used disinfectants on solid surfaces in hospitals or public places. However, peracetic acid is an environmental toxin. Therefore, safer, alternative disinfectants or disinfectant systems should be developed. Because photodynamic virus inactivation with methylene blue (MB)/light system has proven effective in blood banking, MB was selected as a photosensitizing agent, dengue virus as a model virus for enveloped RNA viruses, and an in-house fabricated narrow bandwidth light system overlapping the absorption spectrum of MB as the light source. Dengue virus was mixed with different concentrations of MB, and illuminated by the narrow bandwidth light system under different illumination distances and times. The amount of dengue virus remaining was evaluated by plaque forming assays. Results showed that the concentration of MB working solution, illumination intensity of light source, illumination distance and time were four key factors affecting efficiency of virus inactivation using the MB/narrow bandwidth light system. Dengue virus could be completely inactivated at 2.5 m in 5 min when MB >/= 1.0 microg/ml. However, when the distance reached 3.0 m, only greater concentrations of MB (2.0 microg/ml) could completely inactivate virus in a reasonably short time (20 min), and smaller concentrations of MB (1.0 microg/ml) could only completely inactivate virus using longer times (25 min). The results of this virus inactivation model indicate that our MB/narrow bandwidth light system provides a powerful, easy way to inactivate dengue viruses.
Insights
Methylene blue (MB) and a narrow bandwidth light system effectively inactivate dengue virus. This photodynamic method offers a safer alternative to traditional disinfectants like peracetic acid for public health applications.
Area of Science:
- Virology
- Photochemistry
- Public Health
Background:
- Peracetic acid, a common disinfectant, poses environmental risks.
- Photodynamic inactivation using methylene blue (MB) is effective for blood safety.
- Developing safer disinfectant alternatives is crucial for public spaces.
Purpose of the Study:
- To evaluate the efficacy of a methylene blue (MB)/narrow bandwidth light system for dengue virus inactivation.
- To identify key factors influencing the photodynamic inactivation process.
- To establish optimal conditions for dengue virus elimination.
Main Methods:
- Dengue virus was exposed to varying concentrations of MB and illuminated with a custom narrow bandwidth light source.
- Illumination parameters including distance and time were systematically varied.
- Virus inactivation was quantified using plaque-forming assays.
Main Results:
- Methylene blue concentration, light intensity, distance, and time significantly impacted virus inactivation.
- Complete dengue virus inactivation was achieved at 2.5m with 1.0 µg/ml MB in 5 minutes.
- At 3.0m, higher MB concentrations (2.0 µg/ml) or longer exposure times were required for complete inactivation.
Conclusions:
- The MB/narrow bandwidth light system demonstrates potent and straightforward dengue virus inactivation capabilities.
- This photodynamic approach presents a promising, environmentally friendlier alternative to conventional disinfectants.
- Optimized parameters ensure efficient viral clearance in various settings.
