Folate-containing dextran ligand(FA-Dextran-DTPA) was synthesized by the incorporation of diethylenetriaminepentaacetic acid(DTPA) and folate(FA) as a tumor-targeting group into dextran as a polymer carrier. This ligand was further reacted with gadolinium chloride to make a dextran gadolinium complex FA-Dextran-DTPA-Gd. The ligand and its gadolinium complex were characterized by 1H-NMR, FTIR, UV-Vis, average particle sizes and zeta potential, as well. In vitro properties including relaxivity, cytotoxicity assay, cellular uptake assay, and magnetic resonance imaging(MRI) were also evaluated. Compared with Gd-DTPA, FA-Dextran-DTPA-Gd possessed obviously higher relaxation effectiveness and lower cytotoxicity to He La cells. FA-Dextran-DTPA-Gd had a high affinity to the H460 and MDA-MB-231 tumor cells and can be taken up selectively by these tumor cells. Moreover, FA-Dextran-DTPA-Gd showed enhanced signal intensities(SI) of MRI and enhanced the contrast of MR images of tumor cells. These results indicated that FA-Dextran-DTPA-Gd showed the potential as a tumor-targeting contrast agent in MRI.
