Accelerating Ce3+/Ce4+ Conversion in CeO2 via Mn doping to Endow Scaffolds with Chemodynamic Therapy Properties

CeO 2 nanozymes have garnered significant attention in chemodynamic therapy due to their peroxidase-like activity and ability to deplete glutathione. However, their catalytic efficiency is constrained by the low conversion rate of Ce 3+ /Ce 4+ . To overcome this limitation, the electron transfer was accelerated by introducing the transition metal Mn atom as a valence electron donor through lattice charge transfer. In detail, we introduced Ce 1-x Mn x O 2 into the poly-L-lactic acid (PLLA) scaffold fabricated by selective laser sintering. The conversion from Ce 3+ to Ce 4+ promoted the decomposition of H 2 O 2 within the tumor microenvironment to generate hydroxyl radicals with high oxidative activity, consequently inducing oxidative stress. The conversion from Ce 4+ to Ce 3+ depleted intracellular antioxidant glutathione, disrupting redox balance in tumor cells. This continuous redox cycle ultimately triggered apoptosis in tumor cells. Using a first-principles Hubbard-corrected approximate density-functional method, the analysis of the electron band structure revealed the presence of donor energy levels within the bandgap of Ce 1-x Mn x O 2 , enabling electron transfer channels around 0.645 eV. Electrochemical experiments confirmed that Ce 0.8 Mn 0.2 O 2 significantly reduced the activation overpotential from 0.907 V to 0.646 V, enhancing its redox capacity. As a result, the scaffold exhibited a threefold increase in tumor-killing rate. These findings highlight the immense potential of CeO 2 nanozymes in enhancing chemodynamic therapy for effective tumor treatment.