Tumor-targetable magnetoluminescent silica nanoparticles for bimodal time-gated luminescence/magnetic resonance imaging of cancer cells in vitro and in vivo.

Bimodal photoluminescence-magnetic resonance (MR) imaging technique has attracted tremendous attention due to its great potential in biomedical researches and clinical practices. Herein a novel multifunctional magnetoluminescent nanocomposite, FA-Gd-Tb@SiO2, was found to serve as an effective probe for bimodal time-gated luminescence/MR imaging of cancer cells in vitro and in vivo. The nanopmbe was designed by integrating a luminescent Tb3+ complex, a Gd(III)-based contrast agent and a tumor-targeting molecule, folic acid (FA), into a silica nanoparticle. The integration of these functional moieties allows the nanoprobe to be employed for specific imaging of cancer cells with background-free TGL and non-invasive MR imaging modes. In addition, the optical and magnetic properties were dramatically improved after implicating the newly synthesized nanoarchitecture. In vitro cellular TGL imaging demonstrated that the FA-Gd-Tb@SiO2 nanoprobe could recognize and accumulate in cancer cells overexpressing FA receptor. Furthermore, in vivo study revealed that the as-prepared nanoprobe was able to effectively enhance Ti-weighted MR contrast and TGL intensity in tumor tissue, which might contribute to the precise detection and tracing of cancer cells, as well as diagnosis and therapy of tumor in clinical.