Figure 9 MR imaging of C6 glioma xenograft tumor model. T2-weighted MR images of C6 glioma xenografts that were labeled with 25 μg/mL acetylated APTS-coated Fe3O4 NPs at (a) 7 days, (b) 14 days, (c) 21 days, and (d) 28 days. (e) The R 2 mapping of C6 glioma xenografts that were labeled with 25 μg/mL acetylated APTS-coated Fe3O4 NPs at 14 days. (f) A pseudocolor picture of (e). (g) The R 2 mapping of C6 glioma xenografts without labeling at 14 days as a control. (h) A pseudocolor photo of (g). The white arrows indicate the glioma xenografts. Figure 10 R 2 values of C6 glioma xenografts labeled with 25 μ g/mL Fe 3 O 4 NPs at 7, 14, 21, and 28 days. The R 2 value of C6 glioma xenografts
that were treated with PBS buffer after 14 days was used as a control value. To confirm further the localization of the acetylated APTS-coated GDC-0449 in vitro Fe3O4 NPs in the tumor site, the tumor sections were stained using Prussian blue and observed using an optical microscope (Figure 11). In the sections of the NP-labeled xenografted www.selleckchem.com/products/pci-32765.html tumors that were isolated 14 days
following the injection of the C6 glioma cells, numerous selleck chemicals blue spots were observed to clearly localize in the cytoplasm of the cells, indicating the presence of the Fe3O4 NPs (Figure 11a). In contrast, no blue spots were observed in the negative control (Figure 11b). Our results suggest that the acetylated APTS-coated Fe3O4 NPs can be retained in the tumor site for a comparatively long time, allowing effective MR imaging of tumors. Figure 11 Prussian blue staining of C6 glioma xenografts on the 14th day. (a) The tumor model was labeled with 25 μg/mL of acetylated APTS-coated Fe3O4 NPs (scale bar = 200 μm). (b) A negative PBS control without particle labeling (scale bar = 200 μm). Conclusions In summary, we developed a novel
selleck chemical type of acetylated APTS-coated Fe3O4 NPs with a mean diameter of 6.5 nm for MR imaging both in vitro and in vivo. Combined morphological observation of cells, MTT assays of cell viability, and flow cytometric analyses of cell cycle characteristics indicate that acetylated APTS-coated Fe3O4 NPs do not appreciably affect the cell morphology, viability, or the cell cycle, indicating their good biocompatibility at the given concentration range. Furthermore, Prussian blue staining of cell morphology, TEM imaging, and ICP-AES quantification data indicate that acetylated APTS-coated Fe3O4 NPs are able to be taken up by cells in a concentration-dependent manner. The intracellular uptake of the particles enables effective MR imaging of model tumor cells (e.g., C6 glioma cells) in vitro and in the xenograft tumor model in vivo. Moreover, given the relatively high transverse relaxivity and the tunable amine chemistry of APTS-coated Fe3O4 NPs, which can be further functionalized with various targeting ligands (e.g., folic acid and RGD peptides), it is expected that such NPs may be further biofunctionalized for various biomedical applications, especially for targeted MR imaging.