Nitrogen‐Doped Carbon Quantum Dot Stabilized Magnetic Iron Oxide Nanoprobe for Fluorescence, Magnetic Resonance, and Computed Tomography Triple‐Modal In Vivo Bioimaging

Multimodal imaging, which combines complementary information of two or more imaging modalities, offers huge advantages. In this paper, the synthesis, characterization, and application of superparamagnetic nitrogen-doped carbon-iron oxide hybrid quantum dots (C-Fe3O4 QDs) is reported for triple-modal bioimaging through fluorescence/magnetic resonance/computed tomography (FL/MR/CT). Especially, C-Fe3O4 QDs are synthesized by using poly (γ-glutamic acid) as a precursor and stabilizer via a green and facile one-pot hydrothermal approach. The as-prepared C-Fe3O4 QDs exhibit excellent water dispersibility, wavelength-tunable FL property with high quantum yield of about 21.6%, good photostability, strong superparamagnetic property as well as favorable biocompatibility. Meanwhile, these C-Fe3O4 QDs also show a transverse relaxivity value (r 2) of 154.10 mm −1 s−1 for T2-weighted MR imaging mode and an observable X-ray attenuation effect for CT imaging mode. Moreover, the in vivo bioimaging of tumor-bearing nude mice by combining FL, MR, and CT images further demonstrates that the as-prepared C-Fe3O4 QDs can be readily and efficiently used in FL/MR/CT triple-modal tumor imaging. Hence, the new and facile one-pot synthesis strategy for preparing multifunctional C-Fe3O4 QDs nanoprobes provides a convenient way for achieving an effective and versatile agent for tumorous bioimaging/or diagnostics.