Journal Article

Photo-Antiviral Activity of Cationic and Anionic Dyes

Abstract

Photo-antiviral activity of organic dyes, porphyrins, phthalocyanines, aromatic hydrocarbons and quinones has been shown to be an efficient alternative antiviral agent in the control of resistant and emerging viruses. These high coloured compounds are photosensitisers and in the presence of light and oxygen in solution generates singlet oxygen and other reactive oxygen species which can ultimately inactivate viruses and other microorganisms. Although many photosensitisers can have good yield of singlet oxygen, it has been shown that the type of photosensitiser and the number of their charge in aqueous solution affects the rate and extent of photodynamic inactivation of microorganisms. In this work, we used three (3) different photosensitisers which are TMPyP (tetracationic porphyrin), methylene blue (mono-cationic phenothiazinium dye) and Rose Bengal (dianionic xanthene dye) to carryout photodynamic inactivation of a bacteria virus MS2. The results observed in this study showed that the type and concentration of the photosensitisers, time of illumination and light intensity all affect the rate and extent of PDI of MS2. The photosensitiser TMPyP is the most efficient in facilitating PDI of MS2 compared to the other photosensitisers tested, Rose Bengal and methylene blue. The order of rate and extent of PDI of MS2 by these photosensitisers in solution was TMPyP >>> methylene blue > Rose Bengal. This is likely to be related to the net charge on these photosensitisers as it has been established that cationic photosensitisers are generally more efficient in the PDI of microorganisms including viruses.

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