Latest ArticlesDeveloping non-conjugated luminescent polymers (NCLPs) with fluorescence and long-lived room-temperature phosphorescence is of great significance for revealing the essence of NCLPs luminescence, which has gradually attracted the attention of researchers in recent years. Herein, polymethylol (PMO) and poly(3-butene-1, 2-diol) (PBD) with polyhydroxy structures were prepared and their luminescence behaviors were investigated to reveal the clusteroluminescence (CL) mechanism. Compared with polyvinyl alcohol with non-luminescent behavior, PMO and PBD exhibit cyan-blue fluorescence with quantum yields of ca. 12% and green room-temperature phosphorescence with lifetimes of ca. 89 ms in the solid state. Both fluorescence and phosphorescence exhibit typical excitation-dependent CL behavior. Experimental and theoretical analyses show that the strong hydrogen-bonding interaction of PMO and PBD greatly promotes the formation of oxygen clusters and the through-space n-n interaction of oxygen atoms, enabling fluorescence and phosphorescence emission. Our results have enormous implications for understanding the CL mechanism of NCLPs and provide a new polymer design strategy for the rational design of novel NCLPs materials.
Although endogenous H2O2 is overexpressed in tumor tissue, the amount of endogenous H2O2 is still insufficient for chemodynamic therapy (CDT). In addition, the abundant cellular glutathione (GSH) could also consume •OH for reduced CDT. Thus, the elevation of H2O2 and the consumption of GSH in tumor tissue are essential for the increased •OH yield and amplified CDT efficacy. In this paper, host-guest interactions based supramolecular complexes self-assemblies (SCSAs) were fabricated by incorporating cinnamaldehyde (CA) and PEG-modified cyclodextrin host units (mPEG-CD-CA) with ferrocene-(phenylboronic acid pinacol ester) conjugates (Fc-BE) on the basis of CD-induced host-guest interactions. After being internalized by cancer cells, CA can be released from SCSAs through the pH-responsive acetal linkage, elevating the H2O2 level by activating NADPH oxidase. Then, Fc can catalyze the H2O2 to higher cytotoxic hydroxyl radicals (•OH). Moreover, quinone methide (QM) can be produced through H2O2-induced aryl boronic ester rearrangement and further consume the antioxidant GSH. In vitro and in vivo experiments demonstrate that SCSAs can be provided as potential amplified CDT nanoagents.
Polysubstituted pyrroles are very important scaffolds in many bioactive natural products and synthetic pharmaceuticals. Here, a new gold-catalyzed cycloaddition of alkynes with azadienes to access tetrasubstituted pyrroles is demonstrated. The neighboring hydroxylmethyl group serves a very important directing group through an addition/cycloaddition/elimination cascade. Diverse polysubstituted pyrroles were synthesized in good yields under mild conditions in one step, and tricyclic pyrrole containing heterocycles were easily obtained through derivatization.
We report herein an I2/PhI(OAc)2 catalytic system for the pragmatic construction of CN bonds through CH/NH oxidative coupling protocol. Divergent pyrrolo[2, 3-b]indoles were efficiently prepared via I2-catalyzed intramolecular C–H amination reactions from (E/Z)-2-indolylenamines under metal-free conditions. Various functional groups are tolerated under mild reaction conditions and the resulting pyrrolo[2, 3-b]indoles were obtained with mostly good to excellent yields. It was interesting to observe that both the (E)- and (Z)-isomers of the starting materials were efficiently transformed into the targeted product. The I+-mediated catalytic cycle was proposed based on mechanistic studies for this reaction.
Respiratory antibiotics have been proven clinically beneficial for the treatment of severe lung infections such as Pseudomonas aeruginosa. Maintaining a high local concentration of inhaled antibiotics for an extended time in the lung is crucial to ensure an adequate antimicrobial efficiency. In this study, we aim to investigate whether an extended exposure of ciprofloxacin (CIP), a model fluoroquinolone drug, in the lung epithelial lining fluid (ELF) could be achieved via a controlled-release formulation strategy. CIP solutions were intratracheally instilled to the rat lungs at 3 different rates, i.e., T0h (fast), T2h (medium), and T4h (slow), to mimic different release profiles of inhaled CIP formulations in the lung. Subsequently, the concentration-time profiles of CIP in the plasma and the lung ELF were obtained, respectively, to determine topical exposure index (ELF-Plasma AUC Ratio, EPR). The in silico PBPK model, validated based on the in vivo data, was used to identify the key factors that influence the disposition of CIP in the plasma and lungs. The medium and slow rates groups exhibited much higher EPR than that fast instillation group. The ELF AUC of the medium and slow instillation groups were about 200 times higher than their plasma AUC. In contrast, the ELF AUC of the fast instillation group was only about 20 times higher than the plasma AUC. The generated whole-body PBPK rat model, validated by comparison with the in vivo data, revealed that drug pulmonary absorption rate was the key factor that determined pulmonary absorption of CIP. This study suggests that controlled CIP release from inhaled formulations may extend the exposure of CIP in the ELF post pulmonary administration. It also demonstrates that combining the proposed intratracheal installation model and in silico PBPK model is a useful approach to identify the key factors that influence the absorption and disposition of inhaled medicine.
Lithium-sulfur (Li-S) battery has been considered as one of the most promising next generation energy storage technologies for its overwhelming merits of high theoretical specific capacity (1673 mAh/g), high energy density (2500 Wh/kg), low cost, and environmentally friendliness of sulfur. However, critical drawbacks, including inherent low conductivity of sulfur and Li2S, large volume changes of sulfur cathodes, undesirable shuttling and sluggish redox kinetics of polysulfides, seriously deteriorate the energy density, cycle life and rate capability of Li-S battery, and thus limit its practical applications. Herein, we reviewed the recent developments addressing these problems through iron-based nanomaterials for effective synergistic immobilization as well as conversion reaction kinetics acceleration for polysulfides. The mechanist configurations between different iron-based nanomaterials and polysulfides for entrapment and conversion acceleration were summarized at first. Then we concluded the recent progresses on utilizing various iron-based nanomaterials in Li-S battery as sulfur hosts, separators and cathode interlayers. Finally, we discussed the challenges and perspectives for designing high sulfur loading cathode architectures along with outstanding chemisorption capability and catalytic activity.
MicroRNA-26a (miR-26a) has been verified to promote osteogenic differentiation of mesenchymal stem cells in recent years. The main obstacles to its application in bone regeneration are instability in the physiological environment and low efficiency of cellular membrane penetration. To overcome these problems, we constructed a novel plant virus gene delivery system based on Cowpea chlorotic mottle virus (CCMV). By encapsulating miR-26a with purified capsid protein (CP) dimers derived from CCMV, CP-miR-26a (CP26a) virus-like particles (VLPs) were obtained. CP26a retained a structure similar to the native CCMV and protected miR-26a from digestion with its exterior CP. Moreover, CP26a featured similar cellular uptake efficiency, osteogenesis promotion ability, and better biocompatibility compared with Lipofectamine2000-miR-26a (lipo26a), which indicated a promising prospect for CCMV as a novel gene delivery system.
The SARS-CoV-2 virus is released from an infectious source (such as a sick person) and adsorbed on aerosols, which can form pathogenic microorganism aerosols, which can affect human health through airborne transmission. Efficient sampling and accurate detection of microorganisms in aerosols are the premise and basis for studying their properties and evaluating their hazard. In this study, we built a set of sub-micron aerosol detection platform, and carried out a simulation experiment on the SARS-CoV-2 aerosol in the air by wet-wall cyclone combined with immunomagnetic nanoparticle adsorption sampling and ddPCR. The feasibility of the system in aerosol detection was verified, and the influencing factors in the detection process were experimentally tested. As a result, the sampling efficiency was 29.77%, and extraction efficiency was 98.57%. The minimum detection limit per unit volume of aerosols was 250 copies (102 copies/mL, concentration factor 2.5).
Reversal of regioselectivity in the catalytic asymmetric conjugate additions of 3-substituted oxindoles to β-nitroenones or β-nitroacrylates was established with chiral scandium catalysts. It enabled the construction of functionalized 3, 3-disubstituted oxindoles, including terminal and internal vinyl groups in excellent yields and ee values.
2-Phenylethylamine (2-PEA) is one of the main ingredients for stimulants. Therefore, it is necessary to limit its use and illegal trade by conveniently detecting 2-PEA vapour. Here, a QCM based 2-PEA gas sensor was constructed by using aldehyde functionalized mesoporous carbon (FDU-15-CHO) as sensing materials designed according to Schiff base adsorption role. The 2D hexagonal mesoporous structures of the sensing material have been confirmed by small-angle X-ray diffraction (SXRD), transmission electron microscopy (TEM), and N2 adsorption-desorption isotherms. The covalent grafting of aldehyde group onto the FDU-15 was confirmed by Fourier transform infrared spectroscopy (FT-IR). FDU-15-CHO based Quartz Crystal Microbalance (QCM) sensor shows better sensitivity to 2-PEA than its parent FDU-15. Besides, the detection limit of FDU-15-CHO based sensor can reach down to 1 ppm, and its selectivity and reproducibility are satisfactory. The high concentrations of active sites in the mesopores of FDU-15 are believed to facilitate 2-PEA adsorption, and thus the presence of the -CHO group leading to sensitive and selective response, which is verified by Gaussian simulation
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