Au/CeO2 Nanozyme Scaffold Boosts Electron and Hydrogen Transfer for NIR-Enhanced Chemodynamic Therapy.

Abstract

CeO2 nanozymes have demonstrated the potential to enhance biological scaffolds with chemodynamic therapy. However, their catalytic efficacy is limited by the slow conversion of Ce4+ to Ce3+ and the lack of substrates like H2O2 and H+. To address these challenges, we adopted a dual-pronged strategy that utilized the plasmonic resonance of Au nanoparticles and their glucose-oxidase mimicry to boost electron and hydrogen transfer. Specifically, we integrated Au/CeO2 nanozymes into poly-l-lactic acid scaffolds via selective laser sintering. This conversion of Ce3+ to Ce4+ in the scaffolds enhanced the reduction of H2O2 to a hydroxyl radical, inducing oxidative stress in tumor cells. The Au nanoparticles played a crucial role in boosting the Ce3+/Ce4+ catalytic cycle by providing both the energy and the catalytic substrates. They recycled Ce4+ back to Ce3+ by exploiting plasmonic-induced hot electrons and catalyzed glucose oxidation to supply H2O2 and H+. Our nanoscale and atomic-scale simulations confirmed that the Au/CeO2 hybrid structure utilized near-field coupling to amplify the plasmonic resonance and the Au-O-Ce bridge reduced the electron transfer barrier. Consequently, the Au/CeO2 scaffold decreased the activation energy from 22.57 to 9.92 kJ/mol. These findings highlight the significant promise of the Au/CeO2 nanozyme scaffold for NIR-enhanced chemodynamic therapy.