Extensive efforts are devoted to refining metal sites for optimizing the catalytic performance of single‐atom nanozymes (SANzymes), while the contribution of the defect environment of neighboring metal sites lacks attention. Herein, an iron‐based SANzyme (Fe‐SANzyme) is rationally designed by edge‐site engineering, which intensively exposes edge‐hosted defective Fe–N4 atomic sites anchored in hierarchical mesoporous structures. The Fe‐SANzyme exhibits excellent catalase‐like activity capable of efficiently catalyzing the decomposition of H2O2 into O2 and H2O, with a catalytic kinetic KM value superior to that of natural catalase and reported nanozymes. The mechanistic studies depict that the defects introduce notable charge transfer from the Fe atom to the carbon matrix, making the central Fe more activated to strengthen the interaction with H2O2 and weaken the OO bond. By performing catalase‐like catalysis, the Fe‐SANzyme significantly scavenges reactive oxygen species (ROS) and alleviates oxidative stress, thus eliminating the pathological angiogenesis in animal models of retinal vasculopathies without affecting the repair of normal vessels. This work provides a new way to refine SANzymes by engineering the defect environment and geometric structure around metal sites, and demonstrates the potential therapeutic effects of the nanozyme on retinal vasculopathies.

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Severe uterine injuries may lead to infertility or pregnancy complications. There is a lack of effective methods to restore the structure and function of seriously injured uteri. Leukemia inhibitory factor (LIF), which plays a crucial role in blastocyst implantation, promotes the process of regeneration after injury in several different tissues. In this study, we explored the effect of LIF on the regeneration of rat uterine horns following full-thickness injury. One hundred and twenty four female Sprague-Dawley rats were assigned to three groups, including a sham-operated group (n = 34 uterine horns), a PBS/collagen group (n = 90 uterine horns), and a LIF/collagen group (n = 124 uterine horns). The regenerated uterine horns were collected at 1, 2, 4, 8, or 12 weeks after the surgery. The results showed that LIF/collagen scaffolds increased the number of endometrial cells and neovascularization 2 weeks after uterine full-thickness defect in excision sites (p < 0.001 vs PBS/collagen). Eight weeks after the surgery, the number of endometrial glands was dramatically higher in the LIF/collagen scaffolds group (35.2 AE 4.1/field) than in the PBS/collagen scaffolds (15.1 AE 1.4/field). The percentage of a-smooth muscle actin (a-SMA)-positive areas in the LIF/collagen scaffolds (88.8% AE 9.8%) was also significantly higher than that in the PBS/collagen group (52.9% AE 3.7%). Moreover, LIF improved the pregnancy rate and fetus number. We also found that LIF inhibited the infiltration of inflammatory cells and down-regulated the pro-inflammatory cytokine IL-12 expression while up-regulating the anti-inflammatory cytokine IL-10 expression in the injured part of the uterine horns. Our results indicate that LIF promotes regeneration of the uterus after injury, and this is at least partially due to its immunomodulatory properties. In addition, it is worth to explore further the possibility for LIF/collagen to be an alternative therapeutic approach for uterine damage in the clinic in near future.

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Conjugated porous polymers are emerging as sustainable and reliable electrode materials for lithium-ion batteries, owing to their versatile chemical modification, environmental-friendliness, and low cost, but still suffer from insufficient redox-active...

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