Invivo biodistribution studies and exvivo lymph node imaging using heavy metal-free quantum dots.

Elnaz Yaghini,Klaus Suhling,Imad Naasani,Alexander J Macrobert,Alix M Le Marois,Helen D Turner

doi:10.1016/j.biomaterials.2016.07.014

Elnaz Yaghini, Klaus Suhling + Show 4 more

Open Access

https://doi.org/10.1016/j.biomaterials.2016.07.014

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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.

Highlights

Many cancers metastasise via the lymphatic system, the presence of lymph node metastasis is an important prognostic marker in many cancers including melanoma, breast, colon, lung and ovarian cancers [1,2]
In the case of prolonged exposure (48 h) no significant reduction in cell viability was detected for quantum dot (QD)-treated cells at concentrations as high as 200 nM confirming the good biocompatibility of bio CFQD® nanoparticles
Brunetti et al compared the toxicity of InP/ZnS and CdSe/ZnS QDs in each case capped with mercaptopropionic acid towards A459 human lung carcinoma cells and other cell lines and concluded that leaching of cadmium ions was the main factor responsible for the significantly higher toxicity of the cadmium-containing QDs [48]

Summary

Introduction

Many cancers metastasise via the lymphatic system, the presence of lymph node metastasis is an important prognostic marker in many cancers including melanoma, breast, colon, lung and ovarian cancers [1,2]. Breast cancer cells are most likely to spread to the lymph nodes (LNs) located in the axilla, accurate assessment of the axillary lymph nodes (ALN) is the most prognostic indicator of survival and recurrence in patients with. Axillary lymph node dissection (ALND) has long been used for the management of the breast cancer. In addition patients must stay in hospital for longer with significant cost implications. Most patients with early-stage breast cancer are node negative, and ALND exposes them to the potential side effects of this procedure with no benefit [3e5]

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