Bioinspired porous three-coordinated single-atom Fe nanozyme with oxidase-like activity for tumor visual identification via glutathione

Inspired by structures of natural metalloenzymes, a biomimetic synthetic strategy is developed for scalable synthesis of porous Fe-N-3 single atom nanozymes (pFeSAN) using hemoglobin as Fe-source and template. pFeSAN delivers 3.3- and 8791-fold higher oxidase-like activity than Fe-N-4 and Fe3O4 nanozymes. The high catalytic performance is attributed to (1) the suppressed aggregation of atomically dispersed Fe; (2) facilitated mass transfer and maximized exposure of active sites for the created mesopores by thermal removal of hemoglobin (2 similar to 3 nm); and (3) unique electronic configuration of Fe-N-3 for the oxygen-to-water oxidation pathway (analogy with natural cytochrome c oxidase). The pFeSAN is successfully demonstrated for the rapid colorimetric detection of glutathione with a low limit of detection (2.4 nM) and wide range (50 nM-1 mM), and further developed as a real-time, facile, rapid (similar to 6 min) and precise visualization analysis methodology of tumors via glutathione level, showing its potentials for diagnostic and clinic applications.

Automated summary

Inspired by natural metalloenzymes, a biomimetic strategy was developed to synthesize porous Fe-N-3 single atom nanozymes with high catalytic activity. The performance of the nanozymes surpassed that of other nanozymes due to the suppressed aggregation of atomically dispersed Fe, the optimized mesoporous structure through thermal removal of hemoglobin, and the unique electronic configuration of Fe-N-3.