Latest ArticlesHeme proteins play various important roles in a variety of physiological and pathological processes. Surfactant assemblies have drawn great attention in fabricating fluorescent sensors to detect and identify proteins. In this study, an acetylpyrene fluorophore containing imidazole HP-1 was synthesized, and it could be well modulated by an anionic surfactant sodium dodecyl sulfate (SDS). The selected ensemble based on HP-1/SDS assemblies exhibited selective fluorescence sensing performance towards the heme proteins, including neuroglobin (Ngb), myoglobin (Mb) and cytochrome c (Cyt c). Besides, phospholipid DMPC vesicles as membrane models were particularly explored the association process between the heme protein Mb and membrane. The present work showed that Mb induced the lysis of DMPC liposomes visualized by transmission electron microscopy and optical microscope.
Intramedullary spinal cord tumor (IMSCT) is comparatively rare malignant tumor in the central nervous system and is very difficult accessible by conventional chemotherapy regimen. Currently, there are very limited researches for IMSCT treatment using nanomedicine. To fill this gap, we originally reported a targeted strategy by leveraging nano-engineered mesenchymal stem cells (MSCs) for synergistic anti-IMSCT treatment. In this study, two mode drugs paclitaxel (PTX) and metformin (MET) were co-loaded in maleimide-modified poly(lactic-co-glycolicacid) (PLGA-MAL) nanoparticles, which were further conjugated onto MSCs surface via the thioether bond formed between PLGA-MAL and MSCs without affecting the migration ability of MSCs. Owing to the excellent tumor tropism and penetrability of MSCs and good biodegradability of PLGA, the designed drug delivery platform could accurately target IMSCT sites to exert long-term synergistic antitumor efficacy, exhibiting promising research value for alternative IMSCT management beyond surgery.
The accessibility and mass transfer between catalytic sites and substrates/intermediates are essential to a catalyst's overall performance in oxygen electrocatalysis based energy devices. Here, we present an "in-situ self-sacrifice template etching strategy" for reconstructing MOF-derived M-N-C catalysts, which introduces micro‑meso-macro pores with continuous apertures in a wide range and a central hollow-out structure to optimize the electrochemical oxygen redox kinetics. It is realized via one-step pyrolysis of ZIF-8 single crystal epitaxially coating on a multi-functional template of the Fe, Co co-loaded mesoporous ZnO sphere. The ZnO core is reduced during the general pyrolysis of ZIF-8 into M-N-C and acts as a pore former to etch the surrounding ZIF-8 shell into diverse channels anchoring highly exposed Fe and Co-based active sites with edge enrichment. The redesigned catalyst reveals apparent structural benefits towards enhanced oxygen redox kinetics as bifunctional cathode catalysts of rechargeable zinc-air battery compared with the primitive bulk M-N-C catalysts and the mixture of commercial Pt/C and Ir/C. The unique structure-based activity advantages, the omitted template removal step and good template compatibility during synthesis make the strategy universal for the channel engineering of electrocatalysts.
Zn-gas batteries have attracted great attention in the area of energy conversion and storage owing to their high theoretical energy density in the past decades. In addition to the most widely researched Zn-air/oxygen battery, other novel Zn-gas batteries such as Zn-CO2, Zn-N2 and Zn-NO batteries as "killing two birds with one stone" strategy have emerged to provide energy power and upgrade the pollutant/useless gases simultaneously. This technology becomes more appealing as a low-cost and controllable method to produce value-added chemicals and fuels (such as CO, HCOO−, CH4, NH3) at the cathode driven by surplus electricity. However, there is an absence of a guide for the selection of catalyst and the construction of energy system. Herein, we overview recent achievements in typical Zn-gas batteries beyond Zn-air/oxygen, mainly including Zn-CO2, Zn-N2 and Zn-NO batteries. The energy storage mechanism of these novel Zn-gas batteries has been clearly elaborated. Then, the produced value-added chemicals and the design of cathodic catalyst materials are summarized. Lastly, the remaining challenges and possible directions of Zn-gas batteries, such as highly reduced products, high yield rate and remarkable battery performance, in the future are discussed.
Metal-free heterogeneous photocatalysts provide an environmental-friendly and cost-efficient avenue for green organic synthesis. Covalent organic frameworks (COFs) as heterogeneous photocatalysts showcase promising potential in the field of photocatalytic organic reactions due to their high porosity, insolubility and tailor-made functions. However, thus far, COF-based catalysts only mediated a few types of reactions. Herein, we developed a series of isoreticular nitrogen-rich covalent organic frameworks (N-COFs) with comparable porous structures as photocatalysts which effectively mediated the borylation of aryl iodides with broad substrate scope. Remarkably, 6N-COF exhibits excellent photocatalytic efficiency and superior recyclability. It suggests a new pathway to construct efficient heterogeneous photocatalysts for the borylation of aryl halides.
Plant-parasitic nematodes are major threat for crop protection. The lack of nematicides with new mode of action and increasing resistance raises the need for novel nematicides. In order to seek new nematicidal lead, originating from the structure of chalcone, a series of fused ring compounds was obtained by ring closure design strategy. These compounds were modified further. The nematicidal activity against M. incognita of synthesized compounds was evaluated. The bioassay showed that compound 3 and some of its derivatives such as compounds 18, 19, 21, 22, 23, 24 and 26 exhibited excellent nematicidal activity. Among them, compound 23 exhibited significant bioactivity. The LC50/72 h value reached 3.20 mg/L in vitro and the inhibition rate was 100.00% at 40 mg/L in the matrix. The structure-activity relationship of synthesized compounds was discussed in details. The influence of compound 23 on egg hatching, motility, and feeding behavior of C. elegans was also evaluated.
A new nanocomposite of hollow covalent organic framework (COF) conjugated with the apatinib (AP) and loading microwave-sensitizer (ionic liquid, IL) was prepared by layer by layer (LBL) method and hyaluronic acid (HA) coating, named as COF-AP-IL@HA. AP loading rate in COF hollow-spheres (~30 nm shell thickness) was ~40.3%, due to the interactions of hydrogen and π-π bonds between AP and COF shell, and acidic environment destroyed COF structure, promoting AP release. Microwave sensitization of loaded IL in COF hollow-spheres could enhance the microwave heat-effect, and combined AP therapeutic ability, leading to their higher inhibitation on tumor, due to targeting ability of HA and the local release of apatinib. 88.9% of inhibition rate of COF-AP-IL@HA under microwave on the in vivo tumor was significantly higher than those without microwave (12.3%) and COF-IL@HA with microwave (37.5%), indicating a synergism of sensitized microwave hyperthermia and AP therapy on the reduced expression of VEGF via the downregulation pathway of hypoxia inducible factor. These results indicated that COF-AP-IL@HA was potential to the application in the combination therapy of tumor of the sensitized microwave hyperthermia and apatinib.
Electrochemical is considered an attractive approach to recycling the pollution NO (NORR) and producing the valuable NH3, which could simultaneously solve the two challenging problems, i.e., NO removal and NH3 synthesis. Current research efforts focus less on NORR due to the lack of effective catalysts. Herein, based on DFT calculation, we try to explore effective pyrrole-type TM-N4 (TM = V, Cr, Mn, Fe, Co, Ni, Cu, Ru, Rh, Ta) catalysts for achieving the direct NORR. Among the investigated systems, Fe-N4 exhibits excellent catalytic activity and high NH3 selectivity. Moreover, the free energy of adsorption of N* has been proposed as a descriptor to predict and screen the effective TM-N4 catalyst for NORR and the crystal orbital halmilton populations (COHP) is used to describe the intrinsic relationship between metal atoms and the adsorption free energy of N* intermediate. This work has provided a theoretical picture of TM-N4 catalyzing NO to NH3, which will establish guidelines for the rational design of NORR catalysts and other electrochemical reactions.
The synthesis of active electrode materials at room temperature is one of the effective strategies to reduce the fabrication cost of sodium ion batteries (SIBs). Herein, a layered material (Na2[(VO)2(HPO4)2C2O4]·2H2O, abbreviated as NVPC followingly) with open-framework structures has been successfully prepared at room temperature under ambient conditions and is evaluated as a cathode for SIBs. It is revealed that NVPC cathode can deliver a maximum reversible capacity of ca. 70 mAh/g at 10 mA/g, and exhibit superior rate capability and cycling performance: at 50 mA/g, maximum reversible capacity ca. 50 mAh/g with capacity retention of 88.4% over 250 cycles corresponds to only 0.046% capacity decay per cycle; at 100 mA/g, a maximum reversible capacity of 35 mAh/g with capacity retention of 60.9% over 500 cycles. This study demonstrates a practical example of a low-cost synthesis of the cathode materials for SIBs. At the same time, the systematic electrochemical research results also show promising prospects for long lifespan low-cost SIBs.
Benefiting from the large Stokes shift between fluorescence and phosphorescence, fluorescence/phosphorescence dual-emitting carbon dots (CDs) have gradually entered at the stage of single-phase white light-emitting diodes (WLEDs) as 'green material'. However, most of the developed dual-emitting CDs have weak phosphorescence, short emission wavelength and narrow emission band, resulting in relatively bluish white light emission and low color rendering index (CRI). Herein, an ultrabroad-band fluorescence/phosphorescence dual-emitting CD-based material (UB-CD@BA) is prepared by thermal treatment of boric acid (BA) and CDs with large conjugated structure. The stable covalent bonding between CDs and BA, as well as three-dimensional spatial restriction effect of self-polymerization BA molecules around CDs during long-term heating efficiently rigidified the single/triplet excited states of CDs from non-radiative deactivation, thus producing strong dual emissive materials with the high phosphorescence quantum yield of 21%. Remarkable, the prepared UB-CD@BA powders exhibit bright pure white light emission with Commission Internationale de l'Eclairage (CIE) coordinates of (0.32, 0.33) and the highest reported full width at half maximum of 250 nm. Based on the unique characteristics of UB-CD@BA, it was used as a color conversion layer to prepare a WLED with CIE coordinates of (0.35, 0.33) and the CRI value of 87.