Bubble-templated synthesis of nanocatalyst Co/C as NADH oxidase mimic

Designing highly active nanozymes for various enzymatic reactions remains a challenge in practical applications and fundamental research. In this work, by studying the catalytic functions of natural NADH oxidase (NOX), we devised and synthesized a porous carbon-supported cobalt catalyst (Co/C) to mimic NOX. The Co/C can catalyze dehydrogenation of NADH and transfers electrons to O-2 to produce H2O2. Density functional theory calculations reveal that the Co/C can catalyze O-2 reduction to H2O2 or H2O considerably. The Co/C can also mediate electron transfer from NADH to heme protein cytochrome c, thereby exhibiting cytochrome c reductase-like activity. The Co/C nanoparticles can deplete NADH in cancer cells, induce increase of the reactive oxygen species, lead to impairment of oxidative phosphorylation and decrease in mitochondrial membrane potential, and cause ATP production to be damaged. This 'domino effect' facilitates the cell to approach apoptosis. A unique strategy with melted urea as solvent is developed to fabricate a porous carbon-supported cobalt catalyst to simulate the enzyme-catalyzed electron transfer process.

Automated summary

Designing highly active nanozymes for various enzymatic reactions is a challenging task. In this study, a porous carbon-supported cobalt catalyst was synthesized to mimic the catalytic functions of natural NADH oxidase. The catalyst exhibited a range of catalytic activities and induced a cascade of effects in cancer cells, leading to apoptosis.