3D-Printed Metal-Supported MOF-Heteropoly Acid Nanozyme for High-Performance Peroxidase-Mimic Activity and Ultra-Sensitive Glucose Detection.

The development of nanozymes combining high catalytic activity, mechanical robustness, and scalable fabrication is crucial for next-generation biomedical sensing. However, most current 3D-printed diagnostic platforms rely on polymeric substrates that suffer from limited reusability, weak mechanical strength, and poor long-term stability. Here, we report a sustainable and robust nanozyme system based on a 3D-printed Ti-Al─V alloy substrate, chosen for its excellent mechanical integrity, reusability, and intrinsically rough surface that promotes metal-organic framework growth. For the first time, an iron-based MOF (Fe-BTC) is directly grown on a 3D-printed Ti─Al─V substrates with in situ incorporation of phosphomolybdic acid, forming a highly active Fe-BTC-PMA nanozyme. The rough metallic substrates enable uniform MOF nucleation and strong interfacial anchoring, while electronic interactions between the Ti─Al─V substrate and the Fe-BTC-PMA framework facilitate efficient charge transfer and accelerated redox kinetics. Spectroscopic analyses, including XANES, EXAFS, and XPS, reveal PMA-induced modulation of the iron coordination environment and charge redistribution. These results are supported by kinetic studies, in situ electron paramagnetic resonance spectroscopy, and density functional theory calculations. Compared with conventional powder nanozymes, the integrated platform exhibits enhanced catalytic activity, superior stability, and excellent reusability, enabling sensitive and reliable glucose sensing.