title: In vivo biodistribution studies and ex vivo lymph node imaging using heavy metal-free quantum dots.
abstract: Quantum dots (QDs) are attractive photoluminescence probes for biomedical imaging due to their unique photophysical properties. However, the potential toxicity of QDs has remained a major obstacle to their clinical use because they commonly incorporate the toxic heavy metal cadmium within the core of the QDs. In this work, we have evaluated a novel type of heavy metal-free/cadmium-free and biocompatible QD nanoparticles (bio CFQD(®) nanoparticles) with a good photoluminescence quantum yield. Sentinel lymph node mapping is an increasingly important treatment option in the management of breast cancer. We have demonstrated their potential for lymph node mapping by ex vivo imaging of regional lymph nodes after subcutaneous injection in the paw of rats. Using photoluminescence imaging and chemical extraction measurements based on elemental analysis by inductively coupled plasma mass spectroscopy, the quantum dots are shown to accumulate quickly and selectively in the axillary and thoracic regional lymph nodes. In addition, lifetime imaging microscopy of the QD photoluminescence indicates minimal perturbation to their photoluminescence properties in biological systems.
authors.affiliation: Division of Surgery and Interventional Science and Institute of Healthcare Engineering, University College London, London, UK. Electronic address: elnaz.yaghini@ucl.ac.uk.
authors.forename: Elnaz
authors.initials: E
authors.lastname: Yaghini
authors.affiliation: Nanoco Technologies Ltd., 46 Grafton Street, Manchester, UK.
authors.forename: Helen D
authors.initials: HD
authors.lastname: Turner
authors.affiliation: Department of Physics, King's College London, London, UK.
authors.forename: Alix M
authors.initials: AM
authors.lastname: Le Marois
authors.affiliation: Department of Physics, King's College London, London, UK.
authors.forename: Klaus
authors.initials: K
authors.lastname: Suhling
authors.affiliation: Nanoco Technologies Ltd., 46 Grafton Street, Manchester, UK.
authors.forename: Imad
authors.initials: I
authors.lastname: Naasani
authors.affiliation: Division of Surgery and Interventional Science and Institute of Healthcare Engineering, University College London, London, UK.
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: MacRobert
mesh_terms: D000818:Animals; D005260:Female; D007204:Indium / Q000737:chemistry; D008163:Luminescent Measurements / Q000379:methods*; D053768:Metal Nanoparticles / Q000737:chemistry*; D019216:Metals, Heavy; D045663:Quantum Dots / Q000737:chemistry*; D051381:Rats; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D000071036:Sentinel Lymph Node / Q000737:chemistry* / Q000473:pathology*; D014018:Tissue Distribution
chemical_list: D019216:Metals, Heavy; D007204:Indium
keywords: Breast cancer; Heavy metal-free quantum dots; Nanoparticles; Nanotechnology; Photoluminescence; Sentinel lymph node