Interface Engineering of Prussian Blue-Modified Co-MOF Nanostructure Aerogels Integrated with DNAzyme for Sensitive Antioxidant Sensing

Abstract Metal−organic framework (MOF)-based nanozymes have emerged as promising alternatives to natural enzymes for catalytic sensing due to their tunable porous architectures and abundant active sites. Nevertheless, the practical implementation of pristine Co-MOF nanozymes is severely hindered by intrinsic catalytic activity attenuation, poor structural stability, and unavoidable aggregation issues. In this work, a triple synergistic interface engineering strategy is proposed to fabricate high-performance and recyclable composite nanozymes via Prussian blue (PB) modification, polyvinyl alcohol (PVA) aerogel immobilization, and DNAzyme functionalization. The introduction of PB with self-amplifying catalytic behavior effectively optimizes the redox reaction kinetics of the Co-MOF, significantly boosting its peroxidase-like catalytic activity and structural durability. The three-dimensional porous PVA aerogel serves as a versatile supporting matrix, which not only uniformly disperses PB-modified Co-MOF nanocomposites to eliminate particle aggregation and catalyst waste but also endows the composite with excellent recoverability and cyclic usability. Furthermore, the integration of the hemin/G-quadruplex DNAzyme constructs a multilevel catalytic interface, which synergistically enhances the catalytic efficiency and environmental adaptability of the aerogel-based nanozyme system. Benefiting from the structural superiority and multi-component synergistic catalysis, the optimized DNAzyme@PB/Co-MOF PVA aerogel sensing platform achieves sensitive, stable, and visual detection of the total antioxidant capacity. This work systematically explores the mechanisms of multi-scale composite nanozymes, providing a feasible and universal strategy for the rational design and fabrication of high-stability, high-efficiency, and recyclable MOF-based functional catalytic materials for advanced sensing applications.