Modulation of the biocatalytic activity and selectivity of CeO nanozymes atomic doping engineering.

Artificial enzymes show prospects in biomedical applications due to their stable enzymatic catalytic activity and ease of preparation. CeO nanozymes represent a versatile platform showing multiple enzyme-mimicking activities, although their biocatalytic activities and selectivity are relatively poor for biomedical use. Herein, we developed Mn- and Co-doped CeO nanozymes (M/CeO, M = Mn or Co) atomic engineering to achieve a significant increase in enzyme-like activity. The M/CeO nanozymes exhibited outstanding peroxidase-like activity with a reaction rate about 8-10 times higher than that of CeO. Importantly, the Co/CeO nanozyme preferred for catalase-like activity with a 4-6-fold higher catalytic rate than CeO, while the Mn/CeO nanozyme had a predilection for improving the superoxide dismutase-like capacity. This indicated the selective modulation of enzyme-mimicking activities atomic doping engineering. Cellular level experiments revealed the therapeutic effects of the nanozymes. Mn/CeO and Co/CeO selectively modulated the intracellular redox imbalance in lipopolysaccharide (LPS)- or HO-stimulated nerve cells and improved cell survival. This work provides a feasible strategy for the design of catalytically selective artificial enzymes and facilitates the widespread application of CeO nanozymes in redox-related diseases.