A minimally manipulated preservation and virus inactivation method for amnion/chorion

Allogeneic amnion tissues have been widely used in tissue repair and regeneration, especially a remarkable trend of clinical uses in chronic wound repair. The virus inactivation procedures are necessary and required to be verified for the clinical use and approval of biological products. Cobalt-60 (Co-60) or electron-beam (e-beam) is the common procedure for virus and bacterial reduction, but the excessive dose of irradiation was reported to be harmful to biological products. Herein, we present a riboflavin (RB)-ultraviolet light (UV) method for virus inactivation of amnion and chorion tissues. We used the standard in vitro limiting dilution assay to test the viral reduction capacity of the RB-UV method on amnion or chorion tissues loaded with four types of model viruses. We found RB-UV was a very effective procedure for inactivating viruses of amnion and chorion tissues, which could be used as a complementary method to Co-60 irradiation. In addition, we also screened the washing solutions and drying methods for the retention of growth factors.