Seed-mediated synthesis, properties and application of γ-Fe2O3-CdSe magnetic quantum dots |
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Authors: | Alex WH Lin Pranab K Patra Hongwei Gu Jean Juraszek Georgia C Papaefthymiou Jackie Y Ying |
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Institution: | a Institute of Bioengineering and Nanotechnology, 31 Biopolis Way, The Nanos, Singapore 138669, Singapore b Groupe de Physique des Matériaux, UMR 6634 CNRS, Université de Rouen, Site Universitaire du Madrillet, Avenue de l'Université, BP 12 76801 Saint Etienne du Rouvray Cedex, France c Department of Physics, Villanova University, Villanova, PA 19085, USA |
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Abstract: | Seed-mediated growth of fluorescent CdSe quantum dots (QDs) around γ-Fe2O3 magnetic cores was performed at high temperature (300 °C) in the presence of organic surfactants. Bi-functional magnetic quantum dots (MQDs) with tunable emission properties were successfully prepared. The as-synthesized MQDs were characterized by high-resolution transmission electron microscopy (HRTEM) and dynamic light scattering (DLS), which confirmed the assembly of heterodimers. When a longer growth period was employed, a homogeneous dispersion of QDs around a magnetic nanoparticle was obtained. The magnetic properties of these nanocomposites were examined. The MQDs were superparamagnetic with a saturation magnetization of 0.40 emu/g and a coercivity of 138 Oe at 5 K. To demonstrate their potential application in bio-labeling, these MQDs were coated with a thin silica shell, and functionalized with a polyethylene glycol (PEG) derivative. The functionalized MQDs were effectively used for the labeling of live cell membranes of 4T1 mouse breast cancer cells and HepG2 human liver cancer cells. |
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Keywords: | Magnetic quantum dots Seed-mediated growth Superparamagnetism |
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