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Comparing Intracellular Stability and Targeting of Sulfobetaine Quantum Dots with Other Surface Chemistries in Live Cells

Authors

  • Eleonora Muro,

    1. Laboratoire Physique et Etude des Matériaux UMR8213, ESPCI ParisTech–CNRS - UPMC Sorbonne Universités, 10 rue Vauquelin, 75005 Paris, France
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  • Alexandra Fragola,

    Corresponding author
    1. Laboratoire Physique et Etude des Matériaux UMR8213, ESPCI ParisTech–CNRS - UPMC Sorbonne Universités, 10 rue Vauquelin, 75005 Paris, France
    • Laboratoire Physique et Etude des Matériaux UMR8213, ESPCI ParisTech–CNRS - UPMC Sorbonne Universités, 10 rue Vauquelin, 75005 Paris, France.

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  • Thomas Pons,

    1. Laboratoire Physique et Etude des Matériaux UMR8213, ESPCI ParisTech–CNRS - UPMC Sorbonne Universités, 10 rue Vauquelin, 75005 Paris, France
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  • Nicolas Lequeux,

    1. Laboratoire Physique et Etude des Matériaux UMR8213, ESPCI ParisTech–CNRS - UPMC Sorbonne Universités, 10 rue Vauquelin, 75005 Paris, France
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  • Andriani Ioannou,

    1. Department of Biological Sciences, University of Cyprus, P.O. Box 20537, CY 1678 Nicosia, Cyprus
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  • Paris Skourides,

    1. Department of Biological Sciences, University of Cyprus, P.O. Box 20537, CY 1678 Nicosia, Cyprus
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  • Benoit Dubertret

    1. Laboratoire Physique et Etude des Matériaux UMR8213, ESPCI ParisTech–CNRS - UPMC Sorbonne Universités, 10 rue Vauquelin, 75005 Paris, France
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Abstract

The in vivo labeling of intracellular components with quantum dots (QDs) is very limited because of QD aggregation in the cell cytoplasm and/or QD confinement into lysosomal compartments. In order to improve intracellular targeting with QDs, various surface chemistries and delivery methods have been explored, but they have not yet been compared systematically with respect to the QD intracellular stability. In this work, the intracellular aggregation kinetics of QDs for three different surface chemistries based on ligand exchange or encapsulation with amphiphilic polymers are compared. For each surface chemistry, three delivery methods for bringing the nanoparticles into the cells are compared: electroporation, microinjection, and pinocytosis. It is concluded that the QD intracellular aggregation behavior is strongly dependent on the surface chemistry. QDs coated with dihydrolipoic acid-sulfobetaine (DHLA-SB) ligands diffuse freely in cells for longer periods of time than for QDs in the other chemistries tested, and they can access all cytoplasmic compartments. Even when conjugated to streptavidin, these DHLA-SB QDs remain freely diffusing inside the cytoplasm and unaggregated, and they are able to reach a biotinylated target inside HeLa cells. Such labeling was more efficient when compared to commercial streptavidin-conjugated QDs, which may be due to the smaller size of DHLA-SB QDs and/or to their superior intracellular stability.

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