FeCoNiZnPt high-entropy hierarchical nanosheet-assembled nanozyme with enhanced peroxidase-like activity for colorimetric glucose detection.

The poor stability of natural enzymes and the limited catalytic activity of conventional nanozymes remain major challenges in the field of colorimetric glucose sensing. In this work, a high-entropy hierarchical nanosheet-assembled nanozyme (FeCoNiZnPt-HEHN) composed of Fe, Co, Ni, Zn, and Pt was successfully constructed through a solvothermal strategy. The as-prepared nanozyme exhibits a three-dimensional hierarchical microrod architecture assembled from ultrathin nanosheets, with multiple metal elements uniformly distributed throughout the structure. The synergistic catalytic centers involving Fe2+/Fe3+ mixed-valence species and low-valence Pt0 species were established within the high-entropy framework. Steady-state kinetic analysis demonstrated that FeCoNiZnPt-HEHN possesses excellent affinity toward both hydrogen peroxide (H2O2) and 3,3',5,5'-tetramethylbenzidine (TMB), exhibiting superior peroxidase-like catalytic activity compared with many previously reported nanozyme systems. This enhanced catalytic performance is attributed to the synergistic effects of multimetallic electronic coupling, Fe-based redox cycling, and Pt-mediated interfacial charge transfer, which collectively promote H2O2 activation. By integrating FeCoNiZnPt-HEHN with glucose oxidase (GOx), a cascade colorimetric glucose sensing platform was developed. The proposed system achieved a detection limit of 4.3 μM for glucose and satisfactory recoveries (95.0-101.9% with RSDs below 5.13%) in spiked artificial serum samples. The glucose specificity of the cascade sensing system is mainly provided by the substrate recognition capability of GOx. These results demonstrate that the proposed cascade system (GOx + high-entropy nanozyme) holds great potential for rapid glucose detection in bioanalytical applications.