Non-ionizing 405 nm Light as a Potential Bactericidal Technology for Platelet Safety: Evaluation of Bacterial Inactivation and Platelet Recovery in Severe Combined Immunodeficient Mice.

Bacterial contamination of stored platelets is a cause of transfusion-transmitted infection. Violet-blue 405 nm light has recently demonstrated efficacy in reducing the bacterial burden in blood plasma, and its operational benefits such as non-ionizing nature, penetrability, and non-requirement for photosensitizing agents, provide a unique opportunity to develop this treatment for treatment of stored platelets as a tool for bacterial reduction. Sealed bags of platelet concentrates, seeded with low-level contamination, were 405 nm light-treated (3-10 mWcm) up to 8 h. Antimicrobial efficacy and dose efficiency was evaluated by quantification of the post-treatment surviving bacterial contamination levels. Platelets treated with 10 mWcm for 8 h were further evaluated for survival and recovery in severe combined immunodeficient (SCID) mice. Significant inactivation of bacteria in platelet concentrates was achieved using all irradiance levels, with 99.6-100% inactivation achieved by 8 h ( < 0.05). Analysis of applied dose demonstrated that lower irradiance levels generally resulted in significant decontamination at lower doses: 180 Jcm/10 mWcm ( = 0.008) compared to 43.2 Jcm/3 mWcm ( = 0.002). Additionally, the recovery of light-treated platelets, compared to non-treated platelets, in the murine model showed no significant differences ( = >0.05). This report paves the way for further comprehensive studies to test 405 nm light treatment as a bactericidal technology for stored platelets.