Herein, a new reductive-responsive pillar[5]arene-based, single-molecule-layer polymer nanocapsule is constructed for drug delivery. The functionalized system shows good biocompatibility, efficient internalization into targeted cells and obvious triggered release of entrapped drugs in a reducing environment such as cytoplasm. Besides, this smart vehicle loaded with anticancer drug shows excellent inhibition for tumor cell proliferation and exhibits low side effect on normal cells. This work not only demonstrates the development of a new reductive-responsive single molecular layer polymer nanocapsule for anticancer drug targeting delivery but also extends the design of smart materials for biomedical applications.

The atomically monodispersed dual‐atom nanozyme not only possesses the advantages of homogeneous active centers and high atomic utilization efficiency but also exhibits amazing synergistic effect for higher catalytic activities than single‐atom nanozyme. However, how to construct dual‐atom nanozyme with multi‐enzyme cascade capacity for protecting against brain tissue damage is a great challenge. Herein, for coping with the secondary damage to brain tissue caused by the explosive generation of reactive oxygen species(ROS) during cerebral ischemia‐reperfusion, a multi‐enzyme cascade antioxidant system is constructed by encapsulating dual‐Fe‐atom nanozyme (Fe2NC) in a selenium‐containing MOF (Se‐MOF) shell layer. The designed dual‐Fe‐atom nanozyme exhibits higher superoxide dismutase‐like, catalase‐like, and even oxidase‐like activities than single‐atom Fe (Fe1NC) nanozyme, and moreover, the Se‐MOF shell layer not only acts as a glutathione peroxidase mimic, but also improves the stability and biocompatibility of the Fe2NC nanozyme obviously. The synergistic effect of Fe2NC has been demonstrated to be the main reason for the higher activity by density functional theory calculations. In vitro and in vivo results reveal that the multifunctional antioxidant Fe2NC@Se nanoparticles can counteract oxidative damage and inhibit neural apoptosis after cerebral ischemia‐reperfusion injury by effectively eliminating intracellular ROS and potentially inhibiting the ASK1/JNK apoptotic signaling pathway.

Nanozyme is a type of nanostructured material with intrinsic enzyme mimicking activity, which has been increasingly studied in the biological field. Compared with natural enzymes, nanozymes have many advantages, such as higher stability, higher design flexibility, and more economical production costs. Nanozymes can be used to mimic natural antioxidant enzymes to treat diseases caused by oxidative stress through reasonable design and modification. Oxidative stress is caused by imbalances in the production and elimination of reactive oxygen species (ROS) and reactive nitrogen species (RNS). This continuous oxidative stress can cause damage to some biomolecules and significant destruction to cell structure and function, leading to many physiological diseases. In this paper, the methods to improve the antioxidant properties of nanozymes were reviewed, and the applications of nanozyme antioxidant in the fields of anti-aging, cell protection, anti-inflammation, wound repair, cancer, traumatic brain injury, and nervous system diseases were introduced. Finally, the future challenges and prospects of nanozyme as an ideal antioxidant were discussed.

A peroxidase mimic was firstly fabricated using a covalent assembly strategy, which can be used for highly sensitive glucose detection.