Effects of blue or violet light on the inactivation of Staphylococcus aureus by riboflavin-5′-phosphate photolysis

Tak-Wah Wong, Chien Wei Cheng, Zong Jhe Hsieh, Ji Yuan Liang

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Abstract

The light sensitive compound riboflavin-5′-phosphate (or flavin mononucleotide, FMN) generates reactive oxygen species (ROS) upon photo-irradiation. FMN is required by all flavoproteins because it is a cofactor of biological blue-light receptors. The photochemical effects of FMN after irradiation by blue or violet light on the inactivation of Staphylococcus aureus strains, including a methicillin-resistant strain (MRSA), were investigated in this study. Upon blue- or violet-light photo-treatment, FMN was shown to inactivate S. aureus due to the generated ROS. Effective bacterial inactivation can be achieved by FMN photolysis without an exogenous electron provider. Inactivation rates of 94.9 and 95.2% in S. aureus and MRSA, respectively, can be reached by blue light irradiation (2.0 mW/cm2) with 120 μM FMN for 120 min. A lower FMN concentration and a shorter time are required to reach similar effects by violet light irradiation. Inactivation rates of 96.3 and 97.0% in S. aureus and MRSA, respectively, can be reached by violet light irradiation (1.0 mW/cm2) with 30 μM FMN for 30 min. The sensitivity of the inherent photosensitizers is lower under blue-light irradiation. A long exposure photolytic treatment of FMN by blue light is required to inactivate S. aureus. Violet light was found to be more efficient in S. aureus inactivation at the same radiant intensity. FMN photolysis with blue or violet light irradiation enhanced the inactivation rates of S. aureus and MRSA. FMN photochemical treatment could be a supplemental technique in hygienic decontamination processes.

Original languageEnglish
Pages (from-to)672-680
Number of pages9
JournalJournal of Photochemistry and Photobiology B: Biology
Volume173
DOIs
Publication statusPublished - 2017 Aug 1

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All Science Journal Classification (ASJC) codes

  • Biophysics
  • Radiation
  • Radiological and Ultrasound Technology
  • Radiology Nuclear Medicine and imaging

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