Nanocatalytic therapy, involving the nanozyme-triggered production of reactive oxygen species (ROS) in the tumor microenvironment (TME), has demonstrated potential in tumor therapy, but nanozymes still face challenges of activity and specificity that compromise the therapeutic efficacy. Herein, we report a strategy based on a single-atom nanozyme to initiate cascade enzymatic reactions in the TME for tumorspecific treatment. The cobalt-single-atom nanozyme, with CoÀ N coordination on N-doped porous carbon (Co-SAs@NC), displays catalase-like activity that decomposes cellular endogenous H 2 O 2 to produce O 2 , and subsequent oxidase-like activity that converts O 2 into cytotoxic superoxide radicals to efficiently kill tumor cells. By incorporation with doxorubicin, the therapy achieves a significantly enhanced antitumor effect in vivo. Our findings show that cascade TME-specific catalytic therapy combined with chemotherapy is a promising strategy for efficient tumor therapy.
Here, we report facile
fabrication of two-dimensional (2D) Pd nanosheet
(NS)-supported zero-dimensional (0D) Au nanoparticles via galvanic
replacement. In the synthesis, the surface-clean Pd NSs premade not
only acted as a sacrifice template for replacing Pd atoms by Au3+ ions, but served as a support substrate to support Au nanoparticles.
The morphology, structure, and composition of products relied on the
Au/Pd feed atomic ratio. Interestingly, the as-obtained 0D/2D Au
x
Pd100–x
(x = 4.5, 9.8, and 21) nanocomposites showed remarkably
enhanced peroxidase-mimic catalysis in the model oxidation reaction,
which followed the typical Michaelis–Menten theory. Compared
to Pd NSs, the enhanced catalysis of Au
x
Pd100–x
was closely related to
both the increased specific surface area and the modified electronic
structure of Pd NSs, which resulted in a change in the catalytic pathway,
that is, from hydroxyl radical generation to rapid electron transfer.
The work provides a simple yet efficient avenue to build highly efficient
heterogeneous catalysts based on metallic NSs, as exemplified by the
superior nanozyme activity of 0D/2D bimetallic nanostructures for
glucose detection.
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