As a new family of two-dimensional (2D) nanomaterials, MXenes have recently attracted much attention because of high performance in versatile applications including energy storage and electrochemistry, but their specific application to biomedicine has been rarely reported, especially for theranostic nanomedicine, i.e., concurrent diagnostic imaging and therapy. This study shows for the first time surface engineering and functionalization of 2D Ti₃C₂ MXene nanosheets by the integration of GdW₁₀-based polyoxometalates (POMs). These multifunctional GdW₁₀@Ti₃C₂ composite nanosheets provide hyperthermal treatment with magnetic resonance (MR) and/or computed tomography (CT) imaging guidance toward tumor cells or xenografts. A tumor was effectively eradicated without further reoccurrence during the observation period. GdW₁₀ nanoclusters that were integrated onto the surface of Ti₃C₂ nanosheets were demonstrated to serve as a contrast agent for contrast-enhanced CT and MR imaging based on their unique composition, thus showing the potential for diagnostic-imaging guidance and monitoring for tumor hyperthermia nanotherapy. The high in vivo biocompatibility of GdW₁₀@Ti₃C₂ composite nanosheets was demonstrated to guarantee their subsequent translation into a medical treatment. This study provides a novel strategy for broadening the biomedical applications of MXenes by surface engineering and multifunctionalization, which is expected to promote further exploration of biomedical applications of MXenes in nanotheranostics.

Precise control over the morphology, nanostructure, composition, and particle size of molecularly organic–inorganic hybrid mesoporous organosilica nanoparticles (MONs) still remains a major challenge, which severely restricts their broad applications. In this work, an efficient bridged organic group-determined growth strategy has been proposed for the facile synthesis of highly dispersed and uniform MONs with multifarious Janus morphologies, nanostructures, organic–inorganic hybrid compositions, and particle sizes, which can be easily controlled simply by varying the bridged organic groups and the concentration of bis-silylated organosilica precursors used in the synthesis. In addition, the formation mechanism of Janus MONs determined by the bridged organic group has been discussed. Based on the specific structures, compositions, and asymmetric morphologies, all the synthesized Janus MONs with hollow structures (JHMONs) demonstrate excellent performances in nanomedicine as desirable drug carriers with high drug-loading efficiencies/capacities, pH-responsive drug releasing, and enhanced therapeutic efficiencies, as attractive contrast-enhanced contrast agents for ultrasound imaging, and as excellent bilirubin adsorbents with noticeably high adsorption capacities and high blood compatibilities. The developed versatile synthetic strategy and the obtained JHMONs are extremely important in the development and applications of MONs, particularly in the areas of nanoscience and nanotechnology.