Modulation of the biocatalytic activity and selectivity of CeO2 nanozymes via atomic doping engineering

Artificial enzymes show prospects in biomedical applications due to their stable enzymatic catalytic activity and ease of preparation. CeO2 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 CeO2 nanozymes (M/CeO2, M = Mn or Co) via atomic engineering to achieve a significant increase in enzyme-like activity. The M/CeO2 nanozymes exhibited outstanding peroxidase-like activity with a reaction rate about 8-10 times higher than that of CeO2. Importantly, the Co/CeO2 nanozyme preferred for catalase-like activity with a 4-6-fold higher catalytic rate than CeO2, while the Mn/CeO2 nanozyme had a predilection for improving the superoxide dismutase-like capacity. This indicated the selective modulation of enzyme-mimicking activities via atomic doping engineering. Cellular level experiments revealed the in vitro therapeutic effects of the nanozymes. Mn/CeO2 and Co/CeO2 selectively modulated the intracellular redox imbalance in lipopolysaccharide (LPS)- or H2O2-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 CeO2 nanozymes in redox-related diseases.