Theranostic metal–organic framework core–shell composites for magnetic resonance imaging and drug delivery

Metal–organic frameworks (MOFs) have shown great potential in designing theranostic probes for cancer diagnosis and therapy due to their unique properties, including versatile structures and composition, tunable particle and pore size, enormous porosity, high surface area, and intrinsic biodegradability. In this study, we demonstrate novel MOF-based theranostic Fe3O4@UiO-66 core–shell composites constructed by in situ growth of a UiO-66 MOF shell on a Fe3O4 core for simultaneous drug delivery and magnetic resonance (MR) imaging. In the composites, the UiO-66 shell is devoted for encapsulating the drug, whereas the Fe3O4 core serves as a MR contrast agent. The Fe3O4@UiO-66 core–shell composites show good biocompatibility, high drug loading capacity, sustained drug release, and outstanding MR imaging capability, as well as effective chemotherapeutic efficacy, demonstrating the feasibility of designing theranostic Fe3O4@UiO-66 core–shell composites for cancer diagnosis and therapy.