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The facile fabrication of Gd-labeled superparamagnetic Fe3O4 nanoparticles (NPs) and fluorescent CuInS2 (CIS) quantum dots conjugated with arginine-glycine-aspartic acid (RGD) peptides has been demonstrated, for tri-mode targeted T1-, T2-weighted magnetic resonance (MR) and fluorescence imaging of pancreatic cancer. The core–shell nanocomposites formed are water-dispersible, stable and biocompatible, as confirmed by MTT assay on BXPC-3 cells. Relaxivity measurements show a T1 relaxivity (r1) of 1.56 mM−1 s−1 and a T2 relaxivity (r2) of 23.22 mM−1 s−1, which enable T1- and T2-weighted MR imaging of cancer cells in vitro and in vivo. The MR imaging data clearly indicate that the multifunctional NPs can specifically target cancer cells with αvβ3 integrin over-expression on the cell surface, through a receptor-mediated delivery pathway. The T1-weighted positive and T2-weighted negative enhancement in the MR imaging significantly improves the diagnosis accuracy, and fluorescence imaging of tumor tissue can assist in clinical surgery. These findings suggest that these multifunctional NPs could be used as a platform for bimodal imaging (both MR and fluorescence) in various biological systems. [ABSTRACT FROM AUTHOR]

We synthesized cadmium-free CuInS2–Zn1−xMnxS core–shell quantum dots (QDs) for use in dual-mode optical and magnetic resonance (MR) imaging techniques. Manganese content was in the rang of 0.2–2.3% and varies with the amount of Mn2+ content in the reaction. These materials presented a high quantum yield (QY) of 52% in organic solvent. The CuInS2–Zn1−xMnxS nanoparticles were subsequently transferred to the aqueous phase by the aid of cetyltrimethylammonium bromide (CTAB), and the QY values in water reached 18%. Relaxivity measurements showed that these materials had a T1 relaxivity (r1) of 7.2 mM−1 s−1 on the 3.0 T scanner, suggesting the possibility of using the nanoparticles as a T1 contrast agent. The nanomaterials for both optical and MR imaging in aqueous solution were applied to cells in culture. These results showed that the QY and manganese concentration in the nanoparticles was sufficient to produce contrast for both modalities at relatively low concentrations of nanoparticles. [ABSTRACT FROM AUTHOR]

The facile fabrication of Gd-labeled superparamagnetic Fe 3 O 4 nanoparticles (NPs) and fluorescent CuInS 2 (CIS) quantum dots conjugated with arginine-glycine-aspartic acid (RGD) peptides has been demonstrated, for tri-mode targeted T 1 -, T 2 -weighted magnetic resonance (MR) and fluorescence imaging of pancreatic cancer. The core-shell nanocomposites formed are water-dispersible, stable and biocompatible, as confirmed by MTT assay on BXPC-3 cells. Relaxivity measurements show a T 1 relaxivity (r 1 ) of 1.56 mM -1 s -1 and a T 2 relaxivity (r 2 ) of 23.22 mM -1 s -1 , which enable T 1 - and T 2 -weighted MR imaging of cancer cells in vitro and in vivo. The MR imaging data clearly indicate that the multifunctional NPs can specifically target cancer cells with α v β 3 integrin over-expression on the cell surface, through a receptor-mediated delivery pathway. The T 1 -weighted positive and T 2 -weighted negative enhancement in the MR imaging significantly improves the diagnosis accuracy, and fluorescence imaging of tumor tissue can assist in clinical surgery. These findings suggest that these multifunctional NPs could be used as a platform for bimodal imaging (both MR and fluorescence) in various biological systems.