Latest ArticlesAn unprecedent [4 + 3] cycloaddition of furoketenimines with furocarbenoids has been disclosed for the divergent and efficient synthesis of cycloheptafuran and cycloheptapyrrole scaffolds. Zinc chloride acted as promoters for both the formation of these two transient intermediates from isocyanides and ene-yne-ketones, and the subsequent construction of seven-membered ring. Three rings and five bonds were constructed successively in this three-component one-pot domino reaction.
Highly active and durable oxygen reduction reaction (ORR) catalysts with sufficient activity and stability of Pt are beneficial for the commercialization of proton exchange membrane fuel cells. Here we report an effective approach to prepare a composite catalyst comprising of ordered L12-Pt3Fe intermetallic nanoparticles interact with single atom Fe-Nx-Cy active sites. The addition of Fe and the confinement effect of hierarchical porous structure limit the growth of intermetallic particle size (around 2.5 nm). The ligand effect of the electron transfer from Fe to Pt and the synergistic interaction between L12-Pt3Fe and Fe-Nx-Cy work together to reduce oxygen intermediates adsorption and improve kinetics process. Experimentally, the L12-Pt3Fe/CFe-N-C catalyst shows high mass activity and specific activity at 1.010 A/mgPt and 1.166 mA/cm2, respectively, which are 5.8 and 5.1 times higher than those of commercial Pt/C (0.174 A/mgPt and 0.230 mA/cm2). Thanks to the more stable L12 structure, L12-Pt3Fe/CFe-N-C exhibits better durability (14 mV E1/2 loss of L12-Pt3Fe/CFe-N-C and 33 mV E1/2 loss of commercial Pt/C) after 30,000 cycles accelerated stress tests. The strategy to design and prepare small particle Pt-based intermetallic alloys coordinated with M-N-C active sites provides a new direction to obtain low-cost and easily prepared effective ORR catalysts.
Vascularization and bone regeneration are closely related in the process of bone remodeling, and designing a bioactive scaffold with pro-angiogenic and osteogenic properties may accelerate the repair of bone defects. In this work, an iron-based metal–organic framework (MIL-88) was developed as a carrier for loading a pro-angiogenic small molecular drug (dimethyloxallyl glycine, DMOG), and then embedded into the PLGA nanofibrous scaffolds to repair cranial defects in rats. Imaging and histological evaluation indicated that PLGA/MIL@D scaffold markedly enhanced vascularization and bone regeneration in vivo. Moreover, in vitro assay showed that co-delivery system significantly promoted angiogenesis by stimulating endothelial cell migration, tube formation, and enhanced osteogenesis by promoting expression of osteoblast related proteins. In addition, PLGA/MIL@D scaffold promotes angiogenesis by activating the hypoxia-inducible factor-1 (HIF-1)/vascular endothelial growth factor (VEGF) signaling pathway. Altogether, this bioactive PLGA/MIL@D scaffold can combine angiogenesis with osteogenesis, and will be a bright strategy for the repair of bone defects.
Two-dimensional (2D) layered materials with layer-number dependent properties are promising candidates for next-generation noble-metal-free electrocatalytic reaction. However, the main group metal chalcogenides (MMCs) used for this purpose are rarely explored. Herein, we report the controlled growth of indium selenide (InSe) with a novel morphology (semispherical array) on a silicon substrate and its application in hydrogen evolution reaction (HER). The formation of the spherical InSe is explained with a vapor-liquid-solid growth mechanism, in which the distribution and size of the spheres could be facilely tuned by the reaction parameters. The InSe semispherical array was demonstrated as more efficient catalyst for HER than the flake-like 2D InSe counterparts, originating from the fully exposed InSe spherical surface with abundant adsorbing sites and the high crystalline quality for electron transport. This work provides a controlled synthesis way of the layered InSe with a distinct spherical morphology used for the electrocatalysis applications and could be extended to other main group metal chalcogenides.
Nanomedicines have shown great promise in cancer therapy, but are challenged by limited drug loading, safety concerns of drug carriers, and complexity of function integration. Recently, carrier-free nanomedicines produced by supramolecular assembly of small-molecule therapeutic functionalities and their conjugates were proposed to address these issues. These nanomedicines achieve very high drug loading, enhanced tumor accumulation and improved therapeutic efficiency, and avoid carrier-related safety problems. In this review article, the applications of these nanomedicines in chemotherapy, photodynamic therapy, photothermal therapy as well as combination therapies will be reviewed. The concept of nanomedicine design and mechanism of supramolecular assembly will be discussed. Finally, future perspectives of carrier-free supramolecular nanomedicines for cancer therapy will be highlighted.
Crohn's disease (CD) as a big issue to public health needs an accurate diagnosis urgently that is the common challenge among internal diseases. Herein, we design a mesoporous polydopamine with built-in metal-organic frameworks (dubbed MMP-b-MOFs) to combine with high-throughput mass spectrometry to extract serum peptide fingerprints from CD and healthy controls (HC). Benefitting by the size-exclusion and strong hydrophilicity of MMP-b-MOFs, the extracted peptide fingerprints present extremely high quality. CD and HC are explicitly discriminated with orthogonal partial least squares discriminant analysis (OPLS-DA), the corresponding area under the curve (AUC) value is 1.000. Moreover, eight peptides with clear identity are screened out and achieve the accurate diagnosis and subtype classification of CD, with all AUC values up to 1.000. Moreover, the unsupervised model is also established to precisely classify HC and CD based on these eight clearly identified peptides. This work brings great benefits for clinical detection especially internal medicine.
The design of adhesive materials with strong adhesion capacity at low temperatures is a great challenge. Herein, we report a low-molecular-weight supramolecular adhesive that exhibits good adhesion performance to various surfaces at low temperatures (from −18 ℃ to −80 ℃). Moreover, this supramolecular adhesive has good adhesion ability in the presence of water.
Pt-modified amorphous alloy (Pt@PdNiCuP) catalyst exhibits excellent electro-catalytic activity and high experimental durability for hydrogen evolution reaction (HER). However, the physical origin of the catalytically active remains unclear. In this paper, we constructed a distance contribution descriptor (DCD) for the feature engineering of machine learning (ML) potential, and calculated the Gibbs free energies (ΔGH) of 46,000 *H binding sites on the Pt@PdNiCuP surface by ML-accelerated density functional theory (DFT). The relationship between ΔGH and DCD revealed that in the H-Pt distance region of 2.0–2.5 Å where the parabolic tail and disordered scatters coexist, the H-metal bonding configuration is mainly the bridge- or hollow- bonding type. The contribution analysis of DCD indicates that the joint effect of Pt, Pd and Ni atoms determines the catalytical behavior of amorphous alloy, which agrees well with experimental results. By counting atomic percentages in different energy intervals, we obtained the atomic ratio for the best catalytic performance (Pt:Pd:Ni:Cu:P = 0.33:0.17:0.155:0.16:0.185). Projected density of states (PDOS) show that H 1s orbital, Pt 5d orbital, and Pd 4d orbital form a bonding state at −2 eV. These results provide new ideas for designing more active amorphous alloy catalysts.
Binding of non-activated alkyl halides (2–20) in water-soluble cavitand (1) through supramolecular forces is here reported, with emphasis on the role of size and polarizability of the halogen atom in the formation of intramolecular C-H hydrogen bonds in confined spaces. Rare reverse affinity in water (RI < RBr < RCl) is surprisingly observed for the more water-soluble short alkyl halides in dynamic open-ended containers. Competitive bindings and theoretical calculations confirm the unusual selectivity and the presence of C-H hydrogen bonds in non-activated systems for the first time, pointing out the importance and effect of subtle forces on molecular recognition in confined spaces.
Two-photon imaging has attracted increasing attention owing to its deep tissue imaging capabilities. Therefore, many fluorophores have been developed to satisfy its requirements. However, long-wavelength emission fluorophores with an optically tunable group are rarely developed. In this study, two long-wavelength emission fluorophores with an optically tunable amino group were successfully developed by introducing strong electron acceptor and large conjugated group to the TPQL dye. TPCO2 displayed a bright red emission (λem = 638 nm, Φ = 0.15) together with high two-photon action cross section and good water solubility, which enabled higher signal-to-background ratios and deep tissue imaging. The proof-of-concept probe (TPCONO2) was successfully applied to the high signal-to-background ratio imaging of nitroreductase in liver fibrosis, further realizing diagnosis of the degree of hypoxia during liver fibrosis.