One of the newly approved systems treats plasma by using a solvent and detergent to dissolve lipid membranes, thereby rendering pathogens noninfectious. Another technology, approved for treatment of plasma and platelets, uses a psoralen compound, amotosalen, which binds and cross-links nucleic acids when exposed to ultraviolet A (UVA) light. A third technology using ultraviolet light and riboflavin (vitamin B2) is being tested in trials. Numerous studies demonstrate little substantive negative effect from pathogen reduction on plasma proteins or platelets. Hemoglobin absorption of UVA light prevents treatment of red cells with current pathogen-reduction technologies, but alternatives are in development.