Non-ionizing 405nm light as a potential bactericidal technology for platelet safety: evaluation of in vitro bacterial inactivation and in vivo platelet recovery in severe combined immunodeficient mice

Michelle MacLean, Monique P Gelderman, Sandhya Kulkarni, Rachael M. Tomb, Caitlin F. Stewart, John G. Anderson, Scott J. MacGregor, Chintamani D. Atreya

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Bacterial contamination of ex vivo 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 in situ treatment of ex vivo stored platelets as a tool for bacterial reduction. Sealed bags of platelet concentrates, seeded with low-level Staphylococcus aureus contamination, were 405 nm light-treated (3-10 mWcm-2) up to 8 hr. Antimicrobial efficacy and dose efficiency was evaluated by quantification of the post-treatment surviving bacterial contamination levels. Platelets treated with 10 mWcm-2 for 8 hr 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 hr (P<0.05). Analysis of applied dose demonstrated that lower irradiance levels generally resulted in significant decontamination at lower doses: 180 Jcm-2/10 mWcm-2 (P=0.008) compared to 43.2 Jcm-2/3 mWcm-2 (P=0.002). Additionally, the recovery of light-treated platelets, compared to non-treated platelets, in the murine model showed no significant differences (P ≥ 0.05). This report paves the way for further comprehensive studies to test 405 nm light treatment as a bactericidal technology for stored platelets
Original languageEnglish
Article number331
Number of pages8
JournalFrontiers in Medicine
Publication statusPublished - 15 Jan 2020


  • 405nm light
  • bacteria
  • platelets
  • inactivation
  • violet-blue light
  • pathogen reduction

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