Latest ArticlesErythrocyte membrane (EM)-camouflaged chemotherapeutic delivery nanovehicles hold promise for solid tumor therapy because of their excellent biostability and biocompatibility. However, it is accompanied with insufficient targeting effect and deficient pharmacokinetic behavior due to the lack of a regulated biointerface to navigate and overcome biological transportation obstacles in solid tumor therapy. Herein, an anti-epidermal growth factor receptor (EGFR) aptamer (EApt) modified and EM-cloaked chemotherapeutic nanomissile delivery system was constructed. The anchored-EApt acting as a specific EGFR suppressor promotes to inhibit the overexpression of EGFR and initiate the cell apoptosis. Importantly, the resulting PLGA-DOX@EM-EApt orchestrated the bioactivity of each component and provided synergistic cell apoptosis and antitumor effects by precisely suppressing EGFR expression levels and delivering DOX. The in vitro and in vivo experimental results confirmed that the immune escape and active targeting behaviors of PLGA-DOX@EM-EApt could significantly promote its drug retention and tumor inhibition abilities. Our findings propose a novel strategy using the biointerface functionalization technique, demonstrating a promising therapeutic platform via a biomimetic drug delivery system for precise solid tumor recognition and synergistic therapy.
Lithium rich layered oxide (LRLO) has been considered as one of the promising cathodes for lithium-ion batteries (LIBs). The high voltage and large capacity of LRLO depend on Li2MnO3 phase. To ameliorate the electrochemical performance of Li2MnO3, also written as Li(Li1/3Mn2/3)O2, we propose a strategy to substitute Mn4+ and Li+ in Mn/Li transition metal layer with Ti4+, which can stabilize the structure of Li2MnO3 by inhibiting the excessive oxidation of O2− above 4.5 V. More significantly, the unequal-valent substitution brings about the emergence of interlayer Li vacancies, which can promote the Li-ion diffusion based on the enlarged interlayer and increase the capacity by activating the Mn3+/4+ redox. We designed Li0.7[Li1/3Mn2/3]0.7Ti0.3O2 with high interlayer Li vacancies, which presents a high capacity (290 mAh/g at 10 mA/g) and stable cycling performance (84% over 60 cycles at 50 mA/g). We predict that this strategy will be helpful to further improve the electrochemical performance of LRLOs.
A novel method for HDDA-derived benzyne trapped by nitrone was developed. This research described a simple and efficient pathway for the synthesis of benzisoxazoles from arynes and PTIO (2-phenyl-4, 4, 5, 5-tetramethylimidazoline-3-oxide-1-oxyl), C−C and C−O bonds were formed in a single step without catalyst under mild conditions. The unexpected cleavage of C−N bond contributed to the formation of isoxazole ring, as indicated by DFT studies. Furthermore, we obtained the structure of benzoxazolopyrrolidine when the trapping agent is DMPO (5, 5-dimethyl-1-pyrroline N-oxide).
30% FeCN/ZIS (30% Fe doped g-C3N4 composited ZnIn2S4) was synthesized by a simple water bath method, via in-situ growth of abundant well-dispersed ZnIn2S4 nanosheets on the Fe doped g-C3N4 surface. Experimental results showed the optimized 30% FeCN/ZIS achieved the best photoreduction of Cr(Ⅵ) performance within a wide pH range, which was 9.5 times and 700 times higher than that of pure ZnIn2S4 and 30% FeCN (Fe doped g-C3N4). This is due to the intense synergy between the Fe-Nx bond and close interface contact produces a high-speed charge transfer channel, thus significantly improving the efficiency of optical carrier separation and migration. Meanwhile, UV-vis diffuse reflection spectra and photoluminescence spectroscopy showed that iron doping significantly narrowed the bandgap of g-C3N4, preventing electron-hole pair recombination. Further, the microstructures and charge separation properties were analyzed by scanning electron microscope, Photoluminescence Spectroscopy and time-resolved photoluminescence, which revealed the structure-activity relationship of composite structure and the synergistic mechanism of each functional component. This research should provide a viable technique for creating composites with high photocatalytic activity for the treatment of chromium-containing wastewater.
A new organocatalytic double annulation cascade involving scission/recombination of N-O bonds of nitrones is reported for the first time, and used to produce a range of hitherto unprecedented tricyclic bridged-fused benzo[d]azepines bearing three stereogenic centers with moderate to good yields and complete diastereoselectivity. A quinine-catalyzed reaction of yne-allenone esters with nitrones worked well and provided a convergent and regioselective pathway to access these three-dimensional scaffolds from the planar conjugated system. Density functional theory (DFT) calculations have been applied to understand the key process for forming diradical intermediates.
As a glucagon (GCG) receptor (GCGR) and glucagon-like peptide 1 (GLP-1) receptor (GLP-1R) dual agonist, oxyntomodulin (OXM) has been attracting scientific attentions due to its efficacies of suppressing appetite, increasing energy expenditure, and inducing body weight loss in obese humans. Based on the scaffold of native OXM, specific helix-favoring amino acids substitutions and the consequent salt bridge formations were believed to offer enhanced and balanced GCGR/GLP-1R activations through increasing α-helical conformation. Novel OXM analogues are obtained by intramolecular lactam stapling of positions [Glu16 & Lys20] or [Lys17 & Glu21] to further strengthen conformationally constrained stabilization. Even though the lactam staple does not provide additional dual GCGR/GLP-1R activations in vitro, the stapled OXM analogues are firstly reported to have higher or lower anti-PANC-1 cell proliferation activity, meanwhile which has no obvious inhibitory effect on the proliferation of HeLa cells. Therefore, it is speculated that the stapled analogues may have the potential to inhibit the proliferation of specific cancer cell types. Among the stapled peptides as well as their precursors, analogue 6 has the most prominent anti-PANC-1 proliferation activity with the IC50 value of 115.1 µmol/L. Its mechanism of actions including effective signal pathways should be worth further investigations in future.
Immune rejection, poor biocompatibility and cytotoxicity have seriously stalled the widespread application of biometallic materials. To overcome these problems, biometallic materials with fast and sufficient osseointegration, antibacterial properties and long-term stability have attracted the attention of researchers worldwide. Surface modification is currently used as a general strategy to develop material coatings that will overcome these challenging requirements and achieve the successful performance of implants. In this study, we proposed a substrate surface-modification strategy based on biofilm CsgA proteins that promote rapid cell attachment, proliferation, and stabilization of the cytoskeleton. CsgA-based nano-coating is easy to fabricate and has superior performance, which is expected to expand the application of medical implants.
A novel diterpenoid with an unprecedented 5/6/5/7 tetracyclic system, rhodauricanol A (1), five new grayanane-derived diterpenoids, dauricanols A−E (2−6), and five known ones (7−11) were isolated from the flowers of Rhododendron dauricum. Rhodauricanol A (1) possesses a unique 5/6/5/7 tetracyclic ring system featuring a 16-oxa-tetracyclo[11.2.1.01,5.07,13]hexadecane core. Dauricanols A−C (2−4) are the first 1,3-dioxolane conjugates of grayanane diterpenoids and 5-hydroxymethylfurfural and vanillin, respectively, and dauricanols D (5) and E (6) represent the first examples of 6-deoxy-1,5-seco-grayanane diterpenoids. Their structures were determined by spectroscopic methods, quantum chemical calculation including 13C NMR-DP4+ analysis and ECD calculation, and single-crystal X-ray diffraction analysis. Plausible biosynthetic pathways for 1−4 were proposed. All the isolates showed significant analgesic activities, and dauricanols B (3) and C (4) showed more potent analgesic activities than the positive control, morphine.
Devising a desirable adsorbent for efficiently selective capture of Ag(Ⅰ) from wastewater has attracted much attention but faced with huge challenges. Herein, a novel linear o-phenanthroline-based polymer l-PRL was prepared via chemical oxidative polymerization for the adsorption of Ag(Ⅰ). The maximum adsorption capacity for Ag(Ⅰ) by l-PRL is 325.8 mg/g at pH 0. In addition, l-PRL owes ascendant selectivity for Ag(Ⅰ) from aqueous solutions containing various interfering metal ions of Pb(Ⅱ), Co(Ⅱ), Ni(Ⅱ), Cd(Ⅱ) and Fe(Ⅲ). Multiple characterizations of FT-IR and XPS uncover that the N groups on l-PRL act as adsorption sites to coordinate with Ag(Ⅰ). Density functional theory (DFT) calculations further evidence the mechanism that l-PRL is provided with the admirable adsorptivity and selectivity for Ag(Ⅰ). It is mainly attributed to the most stable complexes of l-PRL with Ag(Ⅰ), which possesses shortest Ag-N bond length compared with other heavy metal ions. Furthermore, 93.5% of initial adsorption capacity is reserved after four continuous regeneration cycles, indicating that l-PRL is equipped with superior recyclability and durability, and l-PRL is capable of removing Ag(Ⅰ) in low-concentration actual Ag(Ⅰ)-containing wastewater completely. This study shed light on the rational design of polymer adsorbents and in-depth insight into selective removal of aqueous Ag(Ⅰ).
The increasing pollution and human demand for a cleaner environment have made achieving the environmental sustainability a current research focus. As a "green" technology, semiconductor photocatalysis is of great significance to the environmental purification. Benefiting from the unique anisotropic crystal structure and electronic properties, layered photocatalytic nanomaterials show great potential for efficient photocatalytic environmental treatment. This review comprehensively summarizes the recent progress on layered photocatalytic nanomaterials for oxidation or reduction of pollutants in water and air along with the basic understanding of related mechanisms and developments in this field. First, the existing diversified layered photocatalysts are classified, and their different synthesis and modification strategies are discussed in detail to provide a comprehensive view of the material design that affects their photocatalytic performance. Subsequently, the extensive applications of the above-mentioned layered photocatalytic nanomaterials in environmental fields are systematically summarized, including photooxidation of water and air pollutants, and photoreduction of heavy metal pollutants, NO3-, BrO3- and CO2. Finally, based on the current research achievements in layered photocatalysts for environmental remediation, the future development direction and challenges are proposed.