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.

Photothermal therapy as a physical therapeutic approach has greatly attracted research interest due to its negligible systemic effects. Among the various photothermal agents, CuS nanoparticles have been widely used due to their easy preparation, low cost, high stability and strong absorption in the NIR region. However, the ambiguous biotoxicity of CuS nanoparticles limited their bio-application. So it is highly desirable to develop biocompatible CuS photothermal agents with the potential of clinical translation. Herein, we report a novel method to synthesize biocompatible CuS nanoparticles for photothermal therapy using bovine serum albumin (BSA) as a template via mimicking biomaterialization processes. Owing to the inherent biocompatibility of BSA, the toxicity assays in vitro and in vivo showed that BSA–CuS nanoparticles possessed good biocompatibility. In vitro and in vivo photothermal therapies were performed and good results were obtained. The bulk of the HeLa cells treated with BSA–CuS nanoparticles under laser irradiation (808 nm) were killed, and the tumor tissues of mice were also successfully eliminated without causing any obvious systemic damage. In summary, a novel strategy for the synthesis of CuS nanoparticles was developed using BSA as the template, and the excellent biocompatibility and efficient photothermal therapy effects of BSA–CuS nanoparticles show great potential as an ideal photothermal agent for cancer treatment.