A simple and convenient Ostwald ripening route to the morphology‐ and phase‐controlled preparation of hollow Sb2S3 microspheres is developed. The hollow spheres are clusters of smaller microspheres if orange amorphous Sb2S3 colloid is used as the precursor, whereas, if starting from the yellow precursor, the products are regular hollow spheres. By selecting appropriate experimental conditions for ripening, the phase of the hollow Sb2S3 microspheres can be controlled. Amorphous and orthorhombic hollow spheres are prepared by ripening the colloidal precursors at ambient temperature and in an autoclave, respectively. The closed shell of hollow Sb2S3 spheres can be easily eroded by hydrochloric acid to form an open structure. By the in situ reduction of adsorbed Ag+ on the surface and interior of the hollow spheres, Ag nanoparticles are introduced into them, to form functional metal–semiconductor composites, the weight content of which is controlled by regulating the concentration of the Ag+ source and the adsorption time. The composite structures composed of Ag nanoparticles and hollow Sb2S3 spheres exhibit a remarkably enhanced absorption covering the UV and visible regions of the electromagnetic spectrum. A study of the photocatalytic properties of the composite structures demonstrates that exposure to both UV and visible light enables them to induce the rapid decomposition of 2‐chlorophenol. The degradation rate increases with a larger weight content of Ag in the composite structure.
Nanofibrous scaffolds that offer proper microenvironmental cues to promote the healing process are highly desirable for patients with chronic wounds. Although studies have shown that fiber organization regulates cell behaviors in vitro, little is known about its effects on the wound healing process in vivo. Most of the nanofibrous scaffolds currently used in skin repair are randomly oriented. Herein, inspired by the basketweave-like pattern of collagen fibrils in native skin, we fabricated biomimetic nanofibrous scaffolds with crossed fiber organization via electrospinning. The regulation of crossed nanofibrous scaffolds on fibroblasts was compared with that of aligned and random nanofibrous scaffolds. Unexpectedly, crossed nanofibrous scaffolds induced different cellular responses in fibroblasts, including differences in cellular morphology, migration and wound healing related gene expression, in comparison to either aligned or random nanofibrous scaffolds. More importantly, the regulation of nanofibrous scaffolds with different fiber organizations on wound repair was systematically investigated in diabetic rats. While the healing processes were enhanced by all nanofibrous scaffolds, wounds treated with crossed nanofibrous scaffolds achieved the best healing outcome, which was evidenced by the resolution of inflammation, the accelerated migration of fibroblasts and keratinocytes, and the promotion of angiogenesis. These findings helped reveal the role of fiber organization in regulating the wound healing process in vivo and suggest the potential utility of biomimetic crossed nanofibrous scaffolds for the repair of chronic wounds.
The synergistic effect of bimetallic heterogeneous catalysis in the reaction of nitrate reduction to nitrogen has been widely discussed, but it is still not clear how this effect works at the atomic scale, hindering the rational design of high-performance catalysts. Here, for the first time, 2D phosphorene was used as a giant P ligand to confine high-density PdCu dual-atom to form a unique PdCuP 4 coordination structure, and this catalyst achieves 96.3 % NO 3 À removal rate and 95.2 % N 2 selectivity. In situ characterization combined with density functional theory (DFT) calculations show that the PdCu dual-atom form covalent-like bonds with adjacent P atoms, reducing the adsorption energy of the reactants. The synergistic effect of PdCu dual-atom promotes the breaking of NÀ O bond, and the short bond length of � 3 Å between PdCu atoms accelerates the transfer of NO 2 À , and eventually the two PdÀ N adjacent to the surface of Pd rapidly combine to form N 2 .
Bioactive glass (BG) can repair bone defects, however, it is not clear whether BG has the ability for bone augmentation without making any bone defect. Unlike the intramembranous osteogenesis in bone defect repair, the extramembranous osteogenesis occurs outside the cortical bone and the osteoprogenitor cells show the reversed migration. Herein, nanoscale bioactive glass scaffolds (BGSs) are fabricated, and their role and immunomodulation-related mechanism in the extramembranous osteogenesis are investigated. The in vitro migration and differentiation of calvaria preosteoblasts are studied by culturing with peripheral macrophage-conditioned medium after stimulating with BGSs. The results indicate that the proinflammatory environment significantly promotes preosteoblast migration, but has limited effect on osteogenic differentiation. However, the anti-inflammatory environment and BGSs significantly increase the osteogenic differentiation of preosteoblasts. The in vivo extramembranous osteogenesis evaluation shows that the active osteogenesis is observed near the skull. The osteoblasts derived from the reverse migration of cranial cells can be confirmed by comparing with the scaffolds implanted in back subcutaneous which is just colonized by fibrous tissue. This study may bring a fresh perspective for BG in bone regeneration and explore the osteogenic immunomodulation of peripheral macrophages in a nonosteogenic environment.
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