Electrochemical Gating of d-Band Engineering in Hierarchically Bridged Dual-Site Nanozymes for Synergistic Cascade Catalysis and Wearable Biosensing
Huining Chai, Xi Sun, Xiao Tan, Zhishuang Yuan, Jing Guan, Xueji Zhang, Jinghe Xie, Guangyao Zhang
Abstract
Cascade nanozymes for biosensing are fundamentally hampered by diffusion limitations and passive catalytic sites. Herein, we report a strategy of electrochemical gating of d-band engineering within a hierarchically bridged dual-site nanozyme (CuNCs@FeMOP) to achieve dynamic control over cascading catalysis. This architecture spatially confines the ascorbic acid oxidase-mimicking copper nanocluster (CuNC) core and the peroxidase-mimicking iron-based microporous organic polymer (FeMOP) shell, eliminating intermediate diffusion losses. More critically, synergistic electronic coupling via a histidine bridge provides static preoptimization of the Cu and Fe sites’ d-band structure, enhancing their intrinsic activities. Upon this foundation, an external electric field acts as a dynamic gate, further modulating the d-band centers of both Cu and Fe sites to synchronously amplify their respective catalytic activities. This dual-mode d-band engineering endows the CuNCs@FeMOP system with exceptional Michaelis–Menten kinetics (low K m, high V max ) far surpassing conventional mixed-catalyst systems. The nanozyme was integrated into a flexible patch for the real-time, colorimetric/electrochemical dual-mode monitoring of ascorbic acid in human sweat, demonstrating its practical utility. This work introduces a paradigm for catalyst design, where gated d-band engineering in bridged, multisite architectures enables programmable control over catalytic processes for advanced wearable diagnostics.