Mechanism of action
Methylene blue is a phenothiazine-based photosensitizer with particular affinity for guanosine-cytosine pairs. It intercalates into viral nucleic acid and subsequent illumination generates singlet oxygen leading to guanosine oxidation and destruction of the viral nucleic acid preventing viral replication.1,2
Bibliography: 1/ S.J. Wagner. Virus inactivation in blood components by photoactive phenothiazine dyes. Transfus Med Rev 2002;16:61–6.
2/ M. Wainwright, H. Mohr, WH. Walker. Phenothiazinium derivatives for pathogen inactivation in blood products. J Photochem Photobiol 2007;86:45–58.