Metal-Organic Framework Multizyme Colloids with Joint Antioxidant and Protease Function

Metal-organic framework (MOF) nanozymes with multiple biocatalytic functions remain scarce, and their colloidal behavior, critical for applications in liquid media, has received limited attention. Here, we report fine aqueous dispersions of a bimetallic CuZr-MOF nanozyme composed of small particles exhibiting a triple enzyme-mimicking activity. Comprehensive microscopy, spectroscopy, and diffraction analyses revealed the structural features of the CuZr-MOF. The surface charges, hydrodynamic sizes, and aggregation rates were systematically investigated in monovalent electrolyte solutions, enabling the identification of well-defined colloidal stability regimes across a broad range of conditions. Pronounced ion specific effects were observed at the solid-liquid interface, and a combined DLVO-Hofmeister description successfully captured the origin of interparticle forces. The CuZr-MOF displayed superoxide dismutase (SOD), horseradish peroxidase (HRP), and, for the first time, protease-like activity, demonstrating a unique combination of antioxidant and hydrolytic functions within a single MOF nanoparticle. The integrated assessment of enzymatic and colloidal properties highlights the strong potential of multifunctional MOF nanozymes for advanced biocatalytic, sensing, and therapeutic applications in liquid-phase environments.