Fabricating Dual-Functional Plasmonic–Magnetic Au@MgFe(2)O(4) Nanohybrids for Photothermal Therapy and Magnetic Resonance Imaging

[Image: see text] Bifunctional nanohybrids possessing both plasmonic and magnetic functionalities are of great interest for biomedical applications owing to their capability for simultaneous therapy and diagnostics. Herein, we fabricate a core–shell structured plasmonic–magnetic nanocomposite system that can serve as a dual-functional agent due to its combined photothermal therapeutic and magnetic resonance imaging (MRI) functions. The photothermal activity of the hybrid is attributed to its plasmonic Au core, which is capable of absorbing near-infrared (NIR) light and converting it into heat. Meanwhile, the magnetic MgFe(2)O(4) shell exerts its ability to act as a MRI contrast agent. Our in vivo studies using tumor-bearing mice demonstrated the nanohybrids’ excellent photothermal and MRI properties. As a photothermal therapeutic agent, the nanohybrids were able to dramatically shrink solid tumors in mice through NIR-induced hyperthermia. As T(2)-weighted MRI contrast agents, the nanohybrids were found capable of substantially reducing the MRI signal intensity of the tumor region at 10 min postinjection. With their dual plasmonic–magnetic functionality, these Au@MgFe(2)O(4) nanohybrids hold great promise not only in the biomedical field but also in the areas of catalysis and optical sensing.