A cerium-based MOFzyme with multi-enzyme-like activity for the disruption and inhibition of fungal recolonization

Abstract

A cerium-based metal–organic framework (Ce-MOF, denoted as AU-1) was synthesized using a solvothermal method by employing 4,4′,4′′-nitrilotribenzoic acid (H₃NTB) as the linker and cerium clusters as the metal center. The material was considered as a MOFzyme based on the peroxidase-like activity of Ce-MOF that could eliminate and kill fungi, such as Aspergillus flavus, Aspergillus niger, Aspergillus terreus, Candida albicans, and Rhodotorula glutinis. Ce-MOF showed high antifungal activity against airborne opportunistic human pathogens isolated from the outside of a hospital. The antifungal activity of CeMOF was evaluated using the colony-forming units, dry mass method, soluble proteins, and microscopic imaging. It exhibited an inhibition efficiency of 93.3–99.3% based on the colony-forming unit method. The Ce-MOF caused extensive deformation of the conidiophores, vesicles, and phialides with growth inhibition between 7.55–77.41% (based on the dry mass method). Ce-MOF showed different efficiencies in inhibiting the different fungal species. The biological activity of Ce-MOF was due to its enzymatic activity, such as those of antioxidants, catalase, superoxide dismutase, and peroxidase. Ce-MOF exhibited excellent enzymatic activity towards the fungal cells. Our results may facilitate the design of a MOFzyme system and pave the way for more profound applications of nanozymes.