High-entropy oxide nanozyme for T/T dual-mode magnetic resonance imaging guided photothermal-nanocatalytic tumor therapy.

High-entropy oxides (HEOs) have attracted significant attention owing to their broad compositional tunability and high catalytic activity. However, research in this area is still in its early stages, and it is necessary to develop uniform multifunctional high-entropy nanozymes with appropriate sizes and excellent catalytic properties. In this study, we synthesized spherical high-entropy oxide composite carbon (HEO/C) nanoparticles (NPs) with a uniform distribution of particle size. The HEO/C NPs showed efficient peroxidase and catalase activities and photothermal conversion properties in the near-infrared (NIR) biological window. Compared to conventional FeO/C NPs, HEO/C NPs exhibited superior NIR-enhanced enzyme-like activities in catalytic applications. Notably, we report, for the first time, that these HEO/C NPs exhibit T/T dual-mode magnetic resonance imaging (MRI) capabilities, outperforming the single-mode T MRI performance of FeO/C NPs. The combination of enzyme-like catalytic and photothermal properties, along with advanced MRI functionality, underscores the significant potential of HEO/C nanozymes for MRI-guided multimodal tumor therapy. This study opens new avenues for the application of high-entropy nanozymes in biomedicine.