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Vers des quantum dots moins toxiques, une approche "safer by design"

Fanny Dussert 1
1 CIBEST - Chimie Interface Biologie pour l’Environnement, la Santé et la Toxicologie
SYMMES - SYstèmes Moléculaires et nanoMatériaux pour l’Energie et la Santé : DRF/IRIG/SYMMES
Abstract : Quantum dots (QDs) are fluorescent semiconductor nanocrystals with exceptional optical properties, which make them particularly attractive in optoelectronic fields and for biomedical applications. However, during their life cycle, the aging of QDs can lead to the degradation of these compounds, inducing the release of toxic elements. Even if toxicity studies on indium-based QDs are still limited, they show a lower intrinsic toxicity in comparison to the heavy metal containing Cd-based QDs. In this context, our laboratory synthetizes different InP QDs with different shell designs, following a safer by design approach, with the aim of producing less toxic QDs with better optical properties. These QDs are composed of a InZnP/Zn(Se,S) core/shell structure which is covered or not by a thick or a thin additional ZnS layer. In this study, primary human keratinocytes which come from breast surgeries, were exposed to these QDs, either pristine or after simulating environmental weathering. First, the physico-chemical transformations of QDs during aging are characterized. Significant photophysical and structural modifications are highlighted and transformation products are identified. However, the results show that these physico-chemical transformations are slowed down by the presence of a double shell, especially when it is thick. Then, the evaluation of QDs toxicity are performed and new assays are developed via high content screening (HCS) on an automated microscope. While pristine QDs were relatively stable and not very toxic to cells, it was not true for their degradation products. Exposure of cells to aged QDs demonstrated high toxicity at low concentrations and modifyed the expression of some genes and proteins essential for cellular homeostasis. These results show that new generations of QDs are safer. However, it’s important to keep improving their photostability since their dissolution and the release of toxic elements at the end of their life are still inevitable.
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https://tel.archives-ouvertes.fr/tel-03227423
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  • HAL Id : tel-03227423, version 1

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Fanny Dussert. Vers des quantum dots moins toxiques, une approche "safer by design". Biologie cellulaire. Université Grenoble Alpes [2020-..], 2020. Français. ⟨NNT : 2020GRALV028⟩. ⟨tel-03227423⟩

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