These results indicate that carboxylated MNC and Apt-MNC are

biocompatible for use as MR imaging probes. Figure 4 Cell viabilities of U87MG cells treated with different concentrations of Apt-MNC and carboxylated MNC. To assess the in vitro VEGFR2-targeting ability of Apt-MNC, VEGFR2-overexpressing PAE/KDR cells were treated with Apt-fluorescein, and the cells Akt inhibitor were analyzed by flow cytometry (Figure  5a). PAE/KDR cells treated with Apt-fluorescein exhibited fluorescence levels of 76.8% (green) when compared with that of non-treated PAE/KDR cells (control, 0.5% fluorescence level, black). PAE/KDR cells treated with Apt-fluorescein were analyzed by confocal microscopy (Figure  5b). Cells exhibited fluorescence in the nuclei (blue, DAPI) and in the cytoplasm (green, fluorescein); this confirmed that Apt could effectively bind to VEGFR2 expressed on PAE/KDR cells. The cellular binding efficiency of Apt-MNC was investigated using dark-field microscopy. In Figure  6, the scattered spots (yellow arrows) on PAE/KDR cells treated with Apt-MNC were observed due to MNC. However, NSC 683864 research buy carboxylate MNC without

Apt conjugation was not observed in non-treated PAE/KDR cells. These results indicate that Apt-MNC effectively targeted VEGFR2-expressing cells [19]. Figure 5 In vitro VEGFR2-targeting ability of Apt. (a) Flow cytometry data of porcine aortic endothelial cells with overexpressing kinase insert domain receptor (PAE/KDR) cells treated with or without Apt-fluorescein. (b) Confocal microscopy images of PAE/KDR cells treated with DAPI (nucleus, blue) and Apt-fluorescein (cytoplasm, green). Figure 6 Dark-field microscopy images

of PAE/KDR Levetiracetam cells. (left panel) Non-treated and (right panel) treated with Apt-MNC; bars = 25 μm. To investigate in vivo VEGFR2-targeting ability of Apt-MNC using MR imaging, we prepared the glioblastoma-bearing mouse xenograft model by intracranial injection of U87MG cells into the brain. Although U87MG cancer cells did not express VEGFR2, they induced extensive VEGFR2 production through a tumor angiogenesis pathway when transplanted into mouse brain [20]. MR imaging for VEGFR2-expressing brain tumor was performed before and after intravenous injection of Apt-MNC and carboxylated MNC into the mouse tail vein (200 μg Fe), and the color map images of Apt-MNC and carboxylated MNC were presented to selleck screening library evaluate accurately the contrast change (Figure  7a). Before the administration of both MNC solutions (pre-injection), each T2-weighted MR image of the tumor site appeared characteristically bright with a low R2 value. Following injection of Apt-MNC or carboxylated MNC (postinjection), we observed that the tumor sites showed darkened images due to the presence of magnetic components.