T1–T2 dual-modal MRI of brain gliomas using PEGylated Gd-doped iron oxide nanoparticles

• A T1–T2 dual-modal contrast agent (PEG-GdIO) were synthesized by the polyol method.
• PEG-GdIO NPs showed a high r1 value and a low r2/r1 ratio.
• The ability of PEG-GdIO NPs in T1–T2 MRI for brain glioma was demonstrated.
• The in vivo and in vitro studies confirmed the biocompatibility of PEG-GdIO NPs.

To overcome the negative contrast limitations of iron oxide-based contrast agents and to improve the biocompatibility of Gd-chelate contrast agents, PEGylated Gd-doped iron oxide (PEG-GdIO) NPs as a T1–T2 dual-modal contrast agent were synthesized by the polyol method. The transverse relaxivity (r2) and longitudinal relaxivity (r1) of PEG-GdIO were determined to be 66.9 and 65.9 mM−1 s−1, respectively. The high r1 value and low r2/r1 ratio make PEG-GdIO NPs suitable as a T1–T2 dual-modal contrast agent. The in vivo MRI demonstrated a brighter contrast enhancement in T1-weighted image and a simultaneous darken effect in T2-weighted MR image compared to the pre-contrast image in the region of glioma. Furthermore, the biocompatibility of PEG-GdIO NPs was confirmed by the in vitro MTT cytotoxicity and in vivo histological analyses (H&E). Therefore, PEG-GdIO NPs hold great potential in T1–T2 dual-modal imaging for the diagnosis of brain glioma.

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