Photodynamic inactivation of viruses by immobilized chlorin- containing liposomes

The viral safety of blood derived products relies in properly chosen inactivation procedures. In this way, it has been reported that some photosensitizers are useful products for blood sterilization. The data presented here show the high incorporation efficiency of the chlorin 3-phorbinepropanol, 9,14-diethyl-4,8,13,18-tetramethyl-20-(3S-trans) (CHL) into anionic unilamellar liposomes, give a protocol for the steric immobilization of chlorin-containing liposomes in a chromatographic support and provide the studies of photodynamic inactivation of bovine viral diarrhea virus (BVDV) and encephalomyocarditis virus (EMCV) with chlorin-containing liposomes, free in solution and immobilized on Sephacryl S-1000 beads. The study demonstrates the successful inactivation of the enveloped virus BVDV by both preparations in culture medium and the resistance of the non-enveloped virus EMCV. The effectiveness of CHL-containing liposomes, in solution and immobilized in the chromatographic support, decreased when the culture media was replaced with human blood plasma. Moreover, the reduction factor of the virus titer after irradiation was smallest when immobilized liposomes were used. Nevertheless, the reduction factor for the virus titers of enveloped viruses after irradiation of human blood plasma samples with immobilized chlorin-containing liposomes increased with the reduction of the sample thickness. The more outstanding aspect of this paper is the design of a system useful for blood sterilization that can be easily removed after photodynamic treatment and, therefore, able to be applied in the manufacturing processes.