Photodynamic inactivation of enveloped viruses by buckminsterfullerene

Photodynamic reactions induced by singlet oxygen-generating agents are known to inactivate enveloped viruses. In this report we demonstrate that the water-insoluble photosensitizer buckminsterfullerene (C60) can be used to mediate the inactivation of enveloped viruses. Viruses from two different families, Semliki Forest virus (SFV, Togaviridae) and vesicular stomatitis virus (VSV, Rhabdoviridae) were used as model systems. Buffered solutions containing C60 plus either of these viruses were illuminated with visible light for up to 5 h, resulting in a loss of infectivity of more than 7 log10/ml (TCID50). Furthermore, it was demonstrated that this viral inactivation was oxygen-dependent and equally efficient in solutions containing protein. C60 yields singlet oxygen in very high amounts and is completely inert to photo-oxidative destruction. In addition, it can be easily removed and recycled from aqueous solutions. For these reasons, it may prove useful in the inactivation of viruses in biological systems.