Natural
enzymes are efficient and versatile biocatalysts but suffer
in their environmental tolerance and catalytic stability. As artificial
enzymes, nanozymes can improve the catalytic stability, but it is
still a challenge to achieve high catalytic activity. Here, we employed
atomic engineering to build the artificial enzyme named Au24Ag1 clusterzyme that hosts an ultrahigh catalytic activity
as well as strong physiological stability via atom manipulation. The
designed Au24Ag1 clusterzyme activates the Ag–S
active site via lattice expansion in the oligomer atom layer, showing
an antioxidant property 72 times higher than that of natural antioxidant
Trolox. Enzyme-mimicked studies find that Au24Ag1 clusterzyme exhibits high catalase-like (CAT-like) and glutathione
peroxidase-like (GPx-like) activity with a maximum reaction rate of
68.9 and 17.8 μM/min, respectively. Meanwhile, the unique catalytic
landscape exhibits distinctive reactions against inflammation by inhibiting
the cytokines at an early stage in the brain. Atomic engineering of
clusterzymes provides a powerful and attractive platform with satisfactory
atomic dispersion for tailoring biocatalysts freely at the atomic
level.
Nanozymes have been widely used as highly active and stable arterial enzyme due to controllable electronic transfer and the unique catalytic reaction route. However, the development of nanozymes are hindered...
The
construction of nanozymes at the atomic level that hold structural
stability and high enzyme-like activity is now a key factor in the
optimization of an artificial enzyme. Single-atom metal/cerium oxide
(CeO2)-based nanozymes have been demonstrated to possess
a variety of enzymatic activities and radical scavenging abilities,
which are mainly attributed to the single-atom active site, redox
valence states, and abundant defect chemistry. Here, we developed
a single-atom Pd/CeO2 nanostructure by aqueous phase synthesis
that exhibits the advantages of high yield and good stability. The
Pd/CeO2 nanostructure possesses peroxidase (POD), superoxide
dismutase (SOD), and catalase (CAT) activities as well as reactive
nitrogen species free-radical scavenging activity, exhibiting multienzyme-like
activities and stability compared with CeO2 and other metal-based
nanozymes. It is worth mentioning that the Pd/CeO2 nanostructure
exhibits high POD-mimicking activity with a reaction rate of 0.88
μM/min, about 5 times higher than that of the CeO2 nanozyme. In addition, the CAT-like activity of the Pd/CeO2 nanostructure is excellent, and its scavenging rate of hydrogen
peroxide reached nearly 100% at a concentration of 50 ng/μL.
The present work shows that single-atom Pd substitution is a promising
strategy for the design of CeO2 nanozymes to exert better
effects on biomedical applications, especially with diseases related
to oxidative stress.
The neural electrodes were used for acquiring neuron signals in brain-machine interfaces, and it is crucial for next-generation neuron engineering and related medical application. Thus, developing flexible, stable and high-resolution...
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