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Updated: Jun 10, 2026

LED-Based In Vitro Screening for Assessing Photoactivable Molecules in Bacterial Photodynamic Inactivation
Published on: January 24, 2025
Methylene blue-mediated photodynamic inactivation as a novel disinfectant of enterovirus 71
Tak-Wah Wong1, Hsuan-Jung Huang, Ya-Fang Wang
1Department of Dermatology, Graduated Institute of Clinical Medicine, National Cheng Kung University Medical College and Hospital, Tainan, Taiwan, Republic of China.
Objectives:
We tested whether methylene blue, an inexpensive and safe photosensitizer, is feasible for photodynamic inactivation of enterovirus 71 (EV71) in the environment.
Methods:
By escalating light doses and photosensitizer concentrations, photoinactivation of EV71 and other enteroviruses was examined in vitro. Viral transmission in the environment was simulated with a neonatal mouse model in vivo. Possible mechanisms were analysed with alterations of viral DNA and proteins after treatments.
Results:
Photodynamic inactivation of EV71 in suspensions occurred in a dose-dependent manner. The optimal condition for photoinactivating EV71 required a light dose of 200 J/cm(2) in the presence of methylene blue. This photodynamic condition was also able to inactivate other enteroviruses, including poliovirus 1 and coxsackieviruses A2, A3, A16 and B3. In an imitation environment, EV71 spread on a solid surface was inactivated by methylene blue-mediated photodynamic inactivation and prevented EV71 transmission to mice. Western blot and RT-PCR analysis indicated that both the viral proteins and the genome were disrupted after photodynamic inactivation.
Conclusions:
Methylene blue-mediated photodynamic inactivation may provide a novel way to eliminate environmentally contaminated sources of EV71 to prevent infection.

