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  • Biodiversity Research  (3)
  • 1
    In: Photochemistry and Photobiology, Wiley, Vol. 98, No. 4 ( 2022-07), p. 736-747
    Abstract: The benefits of contrast‐enhancing imaging probes have become apparent over the past decade. However, there is a gap in the literature when it comes to the assessment of the phototoxic potential of imaging probes and systems emitting visible and/or near‐infrared radiation. The primary mechanism of fluorescent agent phototoxicity is thought to involve the production of reactive molecular species (RMS), yet little has been published on the best practices for safety evaluation of RMS production levels for clinical products. We have proposed methods involving a cell‐free assay to quantify singlet oxygen [(SO) a known RMS] generation of imaging probes, and performed testing of Indocyanine Green (ICG), Proflavine, Methylene Blue, IR700 and IR800 at clinically relevant concentrations and radiant exposures. Results indicated that SO production from IR800 and ICG were more than two orders of magnitude below that of the known SO generator Rose Bengal. Methylene Blue and IR700 produced much higher SO levels than ICG and IR800. These results were in good agreement with data from the literature. While agents that exhibit spectral overlap with the assay may be more prone to errors, our tests for one of these agents (Proflavine) appeared robust. Overall, our results indicate that this methodology shows promise for assessing the phototoxic potential of fluorophores due to SO production.
    Type of Medium: Online Resource
    ISSN: 0031-8655 , 1751-1097
    URL: Issue
    RVK:
    Language: English
    Publisher: Wiley
    Publication Date: 2022
    detail.hit.zdb_id: 2048860-9
    SSG: 12
    Location Call Number Limitation Availability
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  • 2
    In: Photochemistry and Photobiology, Wiley
    Abstract: Various fluorescence imaging agents are currently under clinical studies. Despite significant benefits, phototoxicity is a barrier to the clinical translation of fluorophores. Current regulatory guidelines on medication‐based phototoxicity focus on skin effects during sun exposure. However, with systemic and local administration of fluorophores and targeted illumination, there is now possibility of photochemical damage to deeper tissues during intraoperative imaging procedures. Hence, independent knowledge regarding phototoxicity is required to facilitate the development of fluorescence imaging products. Previously, we studied a cell‐free assay for initial screening of reactive molecular species generation from fluorophores. The current work addresses a safety test method based on cell viability as an adjunct and a comparator with the cell‐free assay. Our goal is to modify and implement an approach based on the in vitro 3T3 neutral red uptake assay of the Organization for Economic Co‐Operation and Development Test Guideline 432 (OECD TG432) to evaluate the photocytotoxicity of clinically relevant fluorophores. These included indocyanine green (ICG), proflavine, methylene blue (MB), and IRDye800, as well as control photosensitizers, benzoporphyrin derivative (BPD) and rose bengal (RB). We performed measurements at agent concentrations and illumination parameters used for clinic imaging. Our results aligned with prior studies, indicating photocytotoxicity in RB and BPD and an absence of reactivity for ICG and IRDye800. DNA interactive agents, proflavine and MB, exhibited drug/light dose–response curves like photosensitizers. This study provides evidence and insights into practices useful for testing the photochemical safety of fluorescence imaging products.
    Type of Medium: Online Resource
    ISSN: 0031-8655 , 1751-1097
    RVK:
    Language: English
    Publisher: Wiley
    Publication Date: 2023
    detail.hit.zdb_id: 2048860-9
    SSG: 12
    Location Call Number Limitation Availability
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  • 3
    In: Photochemistry and Photobiology, Wiley, Vol. 96, No. 2 ( 2020-03), p. 301-309
    Abstract: Fluorescence‐guided surgery (FGS) is routinely utilized in clinical centers around the world, whereas the combination of FGS and photodynamic therapy (PDT) has yet to reach clinical implementation and remains an active area of translational investigations. Two significant challenges to the clinical translation of PDT for brain cancer are as follows: (1) Limited light penetration depth in brain tissues and (2) Poor selectivity and delivery of the appropriate photosensitizers. To address these shortcomings, we developed nanoliposomal protoporphyrin IX (Nal‐PpIX) and nanoliposomal benzoporphyrin derivative (Nal‐BPD) and then evaluated their photodynamic effects as a function of depth in tissue and light fluence using rat brains. Although red light penetration depth (defined as the depth at which the incident optical energy drops to 1/e, ~37%) is typically a few millimeters in tissues, we demonstrated that the remaining optical energy could induce PDT effects up to 2 cm within brain tissues. Photobleaching and singlet oxygen yield studies between Nal‐BPD and Nal‐PpIX suggest that deep‐tissue PDT ( 〉 1 cm) is more effective when using Nal‐BPD. These findings indicate that Nal‐BPD‐PDT is more likely to generate cytotoxic effects deep within the brain and allow for the treatment of brain invading tumor cells centimeters away from the main, resectable tumor mass.
    Type of Medium: Online Resource
    ISSN: 0031-8655 , 1751-1097
    URL: Issue
    RVK:
    Language: English
    Publisher: Wiley
    Publication Date: 2020
    detail.hit.zdb_id: 2048860-9
    SSG: 12
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
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