Investigation of 405-nm light as a pathogen reduction technology for human blood plasma : evaluation of antimicrobial action & protein compatibility

Rights statement
Awarding institution
  • University of Strathclyde
Date of award
  • 2024
Thesis identifier
  • T16955
Person Identifier (Local)
  • 201862135
Qualification Level
Qualification Name
Department, School or Faculty
  • Despite significant advancements in blood transfusion safety, the risk of infectiousagents entering the blood supply remains. Pathogen reduction technologies (PRTs)have been developed to improve blood product safety by proactively treating toremove infectious agents. Whilst these existing PRTs provide broad-spectrumantimicrobial activity, treatments fall short in preserving the quality and functionality of the transfusion products, and are typically limited by the need for photosensitizers and bag transfers which can lead to extensive processing times. Violet-blue 405-nm light recently showed potential to be developed as an alternative, antimicrobial tool for in situ treatment of ex vivo stored blood products, without the need for photosensitizers. The overarching aim of this study was to gain an understanding of the operational factors required to ensure the reliable, repeatable, and effective use of 405-nm light for microbial reduction of prebagged plasma. The first objective investigated the broad-spectrum antimicrobial efficacy and compatibility of 405-nm light using low volume (250 ┬ÁL) plasma samples. These small-scale tests showed that a 360 Jcm-2 dose achieved >95% inactivation for all pathogens investigated across all seeding densities, while displaying compatibility with the plasma itself. The second objectiveexamined whether changing the dose delivery method influenced the antibacterialefficiency and compatibility of the treatment, and demonstrated that use of lowerirradiances provided both greater antibacterial efficiency and treatment compatibilitycompared to higher irradiances when applying a fixed light dose. These small-scalestudies supported the development of a large-scale light unit for treatment of largervolume, prebagged plasma. Initial testing using 100 mL prebagged plasma, as aproof-of-concept to assess the pathogen reduction efficacy and compatibility of 405-nm light, determined that a dose of 115 Jcm-2 was capable of broad-spectrummicrobial inactivation whilst preserving plasma protein integrity and functionality.Testing advanced to more clinically relevant, 300 mL volumes of prebagged plasma,and identified a 405-nm light dose of 288 Jcm-2 as an optimal treatment sufficient toreduce microbial contamination (>96% microbial reductions), whilst not compromisingthe quality of the plasma. Overall, this study presents 405-nm light as an alternative, potentially less damaging PRT for treatment of plasma, compared to existing PRTs which require the use of UVlight and/or addition of photosensitizers, and supports further development of the technology for broader use in transfusion medicine.
Advisor / supervisor
  • MacGregor, Scott
  • Anderson, John
  • MacLean, Michelle
Resource Type