Ultrasmall Nanozymes Isolated within Porous Carbonaceous Frameworks for Synergistic Cancer Therapy: Enhanced Oxidative Damage and Reduced Energy Supply

Due to the robust stability and ultralow cost, nanozymes have been considered as one of the most promising alternatives to natural enzymes in recent years. Generally, shrinking the sizes of nanozymes can generate a large active surface area for catalytic reactions in various practical usages. However, the concomitant increase of surface free energy will intensify the risk of nanozymes' aggregation and further cause the loss of the catalytic ability. To overcome these limitations, we rationally design and fabricate uniformly dispersed ultrasmall nanozymes for the first time by using well-ordered crystalline metal organic frameworks (MOFs) as precursors in this study. Typically, nanosized cerium-based MOFs (Ce-MOFs) are thermally converted into homogeneous cerium oxide nanoparticles (CeO2 NPs) isolated within porous carbonaceous frameworks with a high density via a one-pot facile approach. As expected, excellent characters of these MOF-derived CeO2 NPs including oxidase-like activity, ATP deprivation capacity, and porous structure endow them with admirable oxidative damage effect, specially reduced energy supply ability, and high drug loading capacity. Both in vitro and in vivo results indicate the great promise of these well-prepared nanostructures in synergistic cancer therapy with negligible side effects. Thus, our study paves a new way for the development of high-performance MOFs-derived nanozymes particularly useful for the safe and efficient cancer therapy.