InGaP@ZnS-Enriched Chitosan Nanoparticles: A Versatile Fluorescent Probe for Deep-Tissue Imaging

Authors

  • M. G. Sandros,

    1. Department of Biomedical Engineering, Center for Biorecognition and Biosensors, and McGill Institute for Advanced Materials, McGill University, 3775 University, Montreal, Quebec H3A2B4 (Canada)
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  • M. Behrendt,

    1. Department of Pharmacology and Therapeutics, McGill University, 3655 Promenade Sir-William-Osler, Montreal, Quebec H3G1Y6 (Canada)
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  • D. Maysinger,

    1. Department of Pharmacology and Therapeutics, McGill University, 3655 Promenade Sir-William-Osler, Montreal, Quebec H3G1Y6 (Canada)
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  • M. Tabrizian

    1. Department of Biomedical Engineering, Center for Biorecognition and Biosensors, and McGill Institute for Advanced Materials, McGill University, 3775 University, Montreal, Quebec H3A2B4 (Canada)
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  • This research was funded by the Canadian Institute for Health Research (CIHR), Le Fonds québécois de la recherche sur la nature et les technologies, and the Natural Sciences and Engineering Research Council of Canada (NSERC). We thank Dr. S. Kelly Sears for assistance with TEM.

Abstract

InGaP QDs overcoated with several monolayers of ZnS are covalently bound to chitosan to address the challenges of developing highly biologically stable and fluorescent nanoparticle probes for deep-tissue imaging. Transmission electron microscopy images reveal that the average diameter of these luminescent nanoparticles is approximately 29 nm, and they contain multiple InGaP@ZnS QDs that have an average diameter between 4 and 5 nm. These new InGaP@ZnS–chitosan nanoparticles emit near the near IR region at 670 nm and are able to penetrate three times deeper into tissue (e.g., even through a mouse skull) while revealing a higher uptake efficiency into PC12 cells with a robust signal. Additionally, a cell viability assay demonstrates that these new fluorescent nanoparticles have good biocompatibility and stability with PC12 cells and neural cells. As a result, these near-IR-emitting nanoparticles can be used for real-time and deep-tissue examination of diverse specimens, such as lymphatic organs, kidneys, hearts, and brains, while leaving the tissue intact.

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