Latest ArticlesA hydrogen fluoride-free and chloro-free method for synthesizing LiPF6 was developed. Employing CaF2 as the direct fluorinating reagent instead of hydrogen fluoride made it much safer and more environment-friendly than conventional methods and reduced the metal residues in product owing to the relatively low-acid reaction conditions less corrosive to equipments. The use of P2O5 as phosphorus source instead of traditionally employed PCl5 significantly reduced the chloro residue in product. Ca(H2PO4)2, the only by-product of the process, could be easily converted into Ca3(PO4)2, a best-selling chemical. The above advantages not only reduce the production costs by ca. 20%, but also significantly improve the product purity. The fluorine-oxygen exchange reaction is a completely new technique for LiPF6 production and may bring about technological revolution in the related industry.
A Ru(Ⅲ)-catalyzed annulation reaction of 2-aminoaromatic aldehydes (ketones) and isoxazoles to afford diverse 3-cyanoquinolines has been developed. Notably, isoxazole acted as a cyclization reagent and nontoxic cyano source via N-O bond cleavage and fragmentation. Variously substituted (especially 6- or 7-substituted) quinolines could be easily afforded. This procedure features wide functional group compatibility, efficiency and avoiding toxic cyano source. Meanwhile, this protocol could be successfully applied to scale-up synthesis. Further chemical transformations of 3-cyanoquinoline could give some valuable skeletons, demonstrating its potential in synthetic application
Three polymorphs (forms Ⅰ, Ⅱ and Ⅴ) of isonicotinamide (INA) were mechanically flexible and exhibited one-dimensional (1D) plasticity. Anisotropic intermolecular interactions contribute to the plasticity of single crystals: weak dispersive interactions between slip planes such as 1D columns in forms Ⅰ and Ⅱ or 2D layers in form Ⅴ were stabilized by strong hydrogen bonds, allowing the layer or column's surface to glide smoothly without hindrance. The disparity of intermolecular interactions on plastic properties of INA polymorphic crystals was confirmed by energy framework analysis, nanoindentation tests and micro-Raman spectroscopy. The crystal which exhibits plastic property provides a promising application in pharmaceuticals and material sciences.
We report a Ni-catalyzed three-component cross-electrophile coupling of alkynes with alkenyl halides and fluoroalkyl halides to generate fluoroalkyl-incorporated 1,3-dienes. This mild and operationally simple protocol is distinguished by its broad substrate scope and excellent chemo-, regio-, and stereo-selectivity, offering a new and organometallic agent-free platform for the construction of fluoroalkyl-incorporated diene motifs. Preliminary mechanistic studies have been conducted to probe the potential reaction pathway.
Nanocrystals are of great value in delivering poorly soluble drugs as a technique enables enhanced dissolution and bioavailability. The bottom-up technique allows better control of particle properties. However, the commonly used organic solvents are hazardous to environment and operators, and always lead to large particle size and wide size distribution due to failure on controlling the nucleation and crystal growth. The situation is exacerbated in scale-up production. Therefore, in the proof-of-concept study, we evaluated the feasibility of green and controllable fabrication of drug nanocrystals by using biocompatible ionic liquids (ILs) as solvents. Choline based ILs (Ch-ILs) were synthesized via metathesis reactions. Pure paclitaxel nanocrystals of high quality were obtained from Ch-ILs with surface tension higher than 42 mN/m. The sizes were below 250 nm, while the polydispersity indexes were lower than 0.25. Compared with ethanol, choline lactate is superior in controlling the size of the nanocrystals in scale-up production, where the drug concentration was increased by 6 times. The underlying mechanism may be due to the high viscosity and low surface tension of the ILs, which are supposed to benefit homogeneous and burst nucleation. Ch-ILs can be recycled from the process and recovery rate reached 91.1%. Moreover, the applicability of the green technique was validated in a wider range of model drugs and Ch-ILs. In conclusion, ILs are potent solvents in bottom-up technique for green and controllable fabrication of nanocrystals.
Sugar-dependent targeting and immune adjuvant effects of hyperbranched glycosylated polypeptide nanoparticles were disclosed for ovalbumin (OVA) delivery system. The mannose-coated polypeptide nanoparticles can induce strongest targeting and immune adjuvant effects to macrophages than those glucose/lactose-coated ones, which effectively transported OVA into cells and facilitated OVA subcellular escape from endolysosomes into cytoplasm with the assistance of UV irradiation or intracellular acidic pH.
With an intensive understanding of the mechanism of immune system, developing a therapeutic tumor vaccine is one of the most perspective strategy of cancer immunotherapy. In this study, we report a facile approach to prepare graphene oxide (GO)-based therapeutic cancer-nanovaccine. The model antigen (ovalbumin, OVA) and adjuvant (CpG ODN), are conjugated with GO-PEI nanosheet through electrostatic interaction. The addition of PEG can improve biocompatibility and prevent nanoparticle aggregation. The prepared GO-based nanovaccine, GO-PEI-OVA-PEG-CpG, exhibits good biocompatibility and low toxicity both in vivo and in vitro. More importantly, it can efficiently induce the maturation of dendritic cells (DCs), the enhancement of antigen cross-presentation ability, and the amplification of cytokine production of immune cells. Impressively, this nanovaccine shows a remarkable therapeutic effect against pre-established B16-OVA-melanoma tumors, which can significantly inhibit tumor growth and prolong the survival time of the OVA-expressed tumor-bearing mice. Moreover, combining GO-PEI-OVA-PEG-CpG with NLG919, an IDO-1 (indoleamine-2,3-dioxygenase) inhibitor which can regulate the tumor microenvironment, displays a synergistic therapeutic effect. These findings indicate the GO-PEI-OVA-PEG-CpG nanovaccine actively induces an antigen-specific antitumor immune response and it combined with NLG919 could achieve better therapeutic outcomes.
Aflatoxin B1 (AFB1) is one of the most common mycotoxins that threatens human health. As single-stranded oligonucleotides with high affinity and specificity, aptamers have incomparable effect on the targeted detection of AFB1. Herein, after 11 rounds of selection and analysis using a modified affinity chromatography-based SELEX strategy, the truncated 37 nt aptamer AF11–2 was successfully obtained. The aptamer shows good detection performance for AFB1, and can sensitively detect AFB1 in the range of 100–1000 nmol/L, with a detection limit of 42 nmol/L. In the detection of pretreated edible peanut oil samples, AF11–2 aptamer also showed a high recovery rate and good stability for AFB1, and achieved satisfactory results. In addition, AF11–2 aptamer can significantly enhance the fluorescence ability of AFB1, which is not available in traditional Afla17–2–3 aptamer. After molecular docking analysis, it was found that AF11–2 and Afla17–2–3 had different nucleotide binding sites for AFB1. Afla17–2–3 binds to the carbonyl O of AFB1, while AF11–2 binds to the pyrrolic O of AFB1, which may be the main reason that AF11–2 can enhance the fluorescence of AFB1.
Fluorescence (FL) imaging guided photodynamic therapy (PDT) is becoming highly desirable for personalized therapy and precision medicine. In this study, fluorescent polymer nanoparticles TCPP@PEI/PGA were facilely synthesized through electrostatic interaction-mediated self-assembly of porphyrins tetra(4-carboxyphenyl)porphine (TCPP) and polyethylenimine (PEI), and subsequent surface modification with γ-poly(glutamic acid) (γ-PGA). TCPP served a dual function as the FL imaging probe and the photosensitizer. The as-prepared TCPP@PEI/PGA nanoparticles showed excellent water-solubility and biocompatibility, while having outstanding capabilities of in vivo bioimaging and 1O2 generation. FL bioimaging of mice and effective killing of CT 26 cells as well as CT 26 tumor-bearing mice upon laser irradiation were successfully demonstrated when using TCPP@PEI/PGA as theranostic nanoprobes. This study provides a simple but robust method to design and synthesize porphyrin-based polymer nanoparticles for theranostics.
Novel peptide-fentanyl analogue conjugates were synthesized by the covalent coupling of carfentanyl derivatives to the C-terminus or N-terminus of the conformationally constrained dermorphin tetrapeptide BVD03 via a chemical linker. The carfentanyl-related analogues displayed distinct binding and functional activities at µ/δ opioid receptors (MOR/DOR) and antinociceptive effects when conjugated to the peptide. The most potent compound, SW-LJ-11, displayed mixed MOR/DOR agonist properties in the low nanomolar range and significant analgesic efficacy in vivo in four classic mouse models of pain. Interestingly, SW-LJ-11 did not exhibit any physical dependence or respiratory depression, in contrast to an equipotent analgesic dose of morphine or BVD03, indicating that the use of opioid peptide–fentanyl analogue conjugates as dual MOR/DOR agonists may be a promising strategy for obtaining safer opioids.
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