Construction of a Mesoporous Ceria Hollow Sphere/Enzyme Nanoreactor for Enhanced Cascade Catalytic Antibacterial Therapy

Nanozyme has been regarded as one of the antibacterial agents to kill bacteria via a Fenton-like reaction in the presence of H₂O₂. However, it still suffers drawbacks such as insufficient catalytic activity in near-neutral conditions and the requirement of high H₂O₂ levels, which would minimize the side effects to healthy tissues. Herein, a mesoporous ceria hollow sphere/enzyme nanoreactor is constructed by loading glucose oxidase in the mesoporous ceria hollow sphere nanozyme. Due to the mesoporous framework, large internal voids, and high specific surface area, the obtained nanoreactor can effectively convert the nontoxic glucose into highly toxic hydroxyl radicals via a cascade catalytic reaction. Moreover, the generated glucose acid can decrease the localized pH value, further boosting the peroxidase-like catalytic performance of mesoporous ceria. The generated hydroxyl radicals could damage severely the cell structure of the bacteria and prevent biofilm formation. Moreover, the in vivo experiments demonstrate that the nanoreactor can efficiently eliminate 99.9% of bacteria in the wound tissues and prevent persistent inflammation without damage to normal tissues in mice. This work provides a rational design of a nanoreactor with enhanced catalytic activity, which can covert glucose to hydroxyl radicals and exhibits potential applications in antibacterial therapy.