Methylene Blue


  • Photosensitizer: Methylene blue
  • Tradename: -
  • Company Photosensitizer: German and Swiss Red Cross
  • Clinical Application: Sterilization of freshly frozen plasma
  • Wavelength (nm): 668
  • Extinction Coefficient (M-1 cm-1): 9.53104
  • Mode of Delivery: Ex vivo
  • Delivery vehicle: Water-soluble
  • Typical Dose: 1 mM
  • Light Dose (J cm-2): 50 000 lux
  • Time Post-Injection: n/a
  • Duration of Skin Photosensitivity: n/a

The only photosensitizer currently used in the clinic other than the haematoporphyrin derivatives is methylene blue, which is used by the Swiss and German Red Cross for the decontamination of freshly frozen plasma units[71]. This photosensitizer effectively inactivates extracellularly enveloped viruses[72] and is used in the clinic as a treatment for methaemoglobinaemia, thus showing its lack of toxicity in humans[73].

This phenothiazinium dye has been used extensively for over a century as a biological assay stain and can be used in the clinical diagnosis of a variety of diseases and as a tumour marker in surgery. However, its use as an in vivo photosensitizer is limited by its reduction by ubiquitous cellular enzymes to the colourless form, which is photodynamically inactive[74].

Methylene Blue

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