Photodynamic inactivation of selected bovine viruses by isomeric cationic tetra-platinated porphyrins

Porphyrin-based photodynamic processes have been used for the inactivation of microorganisms and treatment of tumors. The virucidal activity of porphyrins 3-PtTPyP and 4-PtTPyP was investigated against bovine viruses representative of the main structural groups (enveloped/non-enveloped, DNA/RNA: BVDV, BoHV-1, BAV and BEV), and against two epitheliotropic viruses (VSV and VACV). Viral suspensions were incubated at 0.91 [Formula: see text]mol [Formula: see text] L[Formula: see text] and exposed to a white-light LED array source (25 mW [Formula: see text] cm[Formula: see text]; 90 J [Formula: see text] cm[Formula: see text] for 0, 15, 30 and 60 min followed by determination of the remaining virus titers. Porphyrin 3-PtTPyP reduced almost 6 log of VSV and 3.5 log of BVDV titers after 15 min and complete virus photoinactivation was achieved after 30 min. 4-PtTPyP at 0.91 [Formula: see text]mol [Formula: see text] L[Formula: see text] produced reduction of titers of all enveloped virus depending on the time of light irradiation. No virucidal activity of any of the porphyrins was observed for non-enveloped viruses and these results showed the potential of porphyrins to inactivate viruses in premises.

Trends and targets in antiviral phototherapy

Photodynamic therapy (PDT) is a well-established treatment option in the treatment of certain cancerous and pre-cancerous lesions. Though best-known for its application in tumor therapy, historically the photodynamic effect was first demonstrated against bacteria at the beginning of the 20^th century. Today, in light of spreading antibiotic resistance and the rise of new infections, this photodynamic inactivation (PDI) of microbes, such as bacteria, fungi, and viruses, is gaining considerable attention. This review focuses on the PDI of viruses as an alternative treatment in antiviral therapy, but also as a means of viral decontamination, covering mainly the literature of the last decade. The PDI of viruses shares the general action mechanism of photodynamic applications: the irradiation of a dye with light and the subsequent generation of reactive oxygen species (ROS) which are the effective phototoxic agents damaging virus targets by reacting with viral nucleic acids, lipids and proteins. Interestingly, a light-independent antiviral activity has also been found for some of these dyes. This review covers the compound classes employed in the PDI of viruses and their various areas of use. In the medical area, currently two fields stand out in which the PDI of viruses has found broader application: the purification of blood products and the treatment of human papilloma virus manifestations. However, the PDI of viruses has also found interest in such diverse areas as water and surface decontamination, and biosafety.