Hydrothermal and biomineralization synthesis of a dual-modal nanoprobe for targeted near-infrared persistent luminescence and magnetic resonance imaging

The development of the multimodal probes is of great importance for bioimaging application. Herein, we report the fabrication of a functional nanocomposite from near-infrared (NIR) persistent luminescent nanoparticles (PLNPs) and Gd2O3 as a multimodal probe for in vivo NIR persistent luminescence and magnetic resonance (MR) imaging. Small-sized monodispersed NIR ZnGa2O4:Cr3+ PLNPs (ca. 15 nm) were prepared as the NIR persistent luminescence source by a hydrothermal method while hyaluronic acid (HA) functionalized Gd2O3 (HA-Gd2O3) was synthesized as the MR contrast agent via a biomineralization approach. An EDC/NHS coupling strategy was used to connect the amino functionalized PLNPs and the HA-Gd2O3 to give the HA functionalized multimodal probe. The multimodal probe not only exhibits an excellent NIR persistent luminescence signal, but also exhibits larger longitudinal relaxivity (7.38 mM-1 s-1) than commercial contrast agent Gd-DTPA. Moreover, the HA moieties not only enhance the biocompatibility of the multimodal probe, but also endow the probe with tumor-targeting capability. Both in vitro and in vivo bioimaging experiments demonstrate the potential of the multimodal probe for tumor-targeting NIR persistent luminescence and MR imaging.