Latest ArticlesAcid-catalyzed tandem reactions were established by employing a novel class of 2-arylglycerol derivative, 5-aryl-1, 3-dioxan-5-ol, as versatile 1, 3-biselectrophile. In the reactions, 5-aryl-1, 3-dioxan-5-ol works like atropaldehydes or 2-aryl malondialdehydes, and can react with 2-naphthols and β-keto amides, allowing the synthesis of 4H-chromenes and 5-aryl-2-pyridinones. High yields, good functional group tolerance, broad substrate scope and simple reaction operation make this protocol attractive.
The visible light induced multicomponent reaction of styrene, carbon disulfide, amine and ethyl difluorobromoacetate for the synthesis of thiodifluoroesters is disclosed. This developed protocol offers a facile and general route to access various valuable thiodifluoroesters in moderate to good yields. Preliminary mechanistic studies revealed that a radical process might be involved in this transformation.
Multiple myeloma (MM) is the second most common hematological tumor characterized by the proliferation of monoclonal plasma cells. Melphalan (MEL) is commonly used in the treatment of MM and is especially essential for patients undergoing autologous stem cell transplantation (ASCT). Although many drugs for MM have been developed in recent years, chemotherapy followed by ASCT remains the optimal option. Melphalan, the backbone of the conditioning regimen, brings severe toxicities at a high dose. Nanodrug delivery systems enable drugs to be highly effective and have low toxicity. In this study, methoxy poly(ethylene glycol)-poly(D, L-lactide) copolymer (MPEG-PDLLA) was chosen to encapsulate melphalan, and the characteristics, effectiveness, and safety of MEL/MPEG-PDLLA in vitro and in vivo were investigated. MEL/MPEG-PDLLA showed slow release and was easily engulfed by MM cells despite a result of the antitumor assay comparable to that of free melphalan in vitro. The in vivo results showed that MEL/MPEG-PDLLA could significantly alleviate tumor burden and prolong survival time without increasing the toxicity to vital organs. In addition, MEL/MPEG-PDLLA could significantly reduce the damage to the intestinal mucosa caused by melphalan. In conclusion, MEL/MPEG-PDLLA shows improved antitumor activity and has the potential to alleviate pains of MM patients undergoing ASCT.
Engineering small-molecule drugs into nanoparticulate formulations provides an unprecedented opportunity to improve the performance of traditional chemo drugs, but suffers from poor compatibility between drugs and nanocarriers. Stimuli-responsive mPEG-PDLLA–drug conjugate-based nanomedicines can facilitate the exploitation of beneficial properties of the carrier and enable the practical fabrication of highly efficacious self-assembled nanomedicines. However, the influence of hydrophobic length on the performance of this type of nanomedicine is little known. Here we synthesized two acid-sensitive ketal-linked mPEG-PDLLA–docetaxel prodrugs with different lengths of PDLLA, and engineered them into self-assembled sub-20 nm micellar nanomedicines for breast cancer chemotherapy. We found that the nanomedicine consisting of a mPEG-PDLLA–docetaxel prodrug with the shorter length of PDLLA stood out due to its potent cytotoxicity, deep penetration into multicellular spheroids, and improved in vivo anticancer performance. Additionally, our prodrug-based nanomedicines outperformed the generic formulation of commercial Nanoxel in terms of safety profile, tolerated doses, and tumor suppression. Our findings indicate that the hydrophobic content of a polymeric prodrug nanomedicine plays an important role in the performance of the nanomedicine, and should be instructive for developing polymeric prodrug-based nanomedicines with clinical translational potential.
Ultrasonography is an important complement to clinical diagnosis, and the application of microbubbles effectively improved diagnostic accuracy in echography. In scientific research, the sizes of microbubbles range from nanometers to microns. By optimizing the fabrication process, bubble sizes and ultrasound parameters, microbubbles can also be used for drug delivery and therapeutic monitoring. In this review, we summarize the recent advances in the diagnosis and treatment of microbubbles according to their different components. Modification of microbubble shells allows for more accurate imaging and detection and the combined utilization of US-targeted MB destruction (UTMD) allows for non-invasive, precise and targeted delivery of drug molecules to pathological tissues. These features pave the way for the emerge of theranostic microbubbles by combination of functional compositions and the application of multifunctional materials. Theranostic microbubbles allow for the simultaneous process of diagnosis, visualization of drug delivery and therapeutic monitoring. Ultimately, theranostic microbubbles are promising in clinical practice and would enhance contrast-enhanced US (CEUS) to a new qualitative level.
An algorithm capable of predicting and optimizing the gradient separation of LC × LC system was developed in this paper. Two groups of structural analogues, five ginsenosides as well as eight bisphenols, which were difficult to discriminate in routine analysis, were used to verify the effectiveness of the proposed algorithm in fast separation optimization. Average errors of retention times below 1% were found in the retention prediction for all types of gradient programs, implying that the theory could lead to high quality in prediction of the retention times under gradients elution. Meanwhile, 84% of relative average deviations (RADs) between the predicted peak width and the measured ones were less than 20%. The larger deviation occurred at the time when the peak appeared while the gradient of the mobile phase changed, which led the deviations increased to 20%–42%. In all, method development and optimization for LC × LC tandem system was realized by the homemade user-friendly software. The present protocol may turn on great opportunities for the convenient method development in analysis of trace structural analogues in environmental, food and biological samples.
Compared with other types of breast cancer, triple-negative breast cancer (TNBC) has the characteristics of a high degree of malignancy and poor prognosis. Early diagnosis of TNBC through biological markers and timely development of effective treatment methods can reduce its mortality. Many Research experiments have confirmed that some specific miRNA expression profiles in TNBC can used as markers for early diagnosis. However, detecting the expression profiles of multiple groups of miRNAs according to traditional detection methods is complicated and consumes many samples. To address this issue, we developed a method for high-throughput, high-sensitivity quantitative detection of multiple sets of miRNAs (including miR-16, miR-21, miR-92, miR-199, and miR-342) specifically expressed in TNBC by rolling circle amplification (RCA) on fluorescence-encoded microspheres. Through the optimization of reaction system conditions, the developed method showed an extensive linear dynamic range and high sensitivity for all five miRNAs with the lowest limit of detection of 2 fmol/L. Meanwhile, this high-throughput detection method also appeared reasonable specificity. Only in the presence of a specific target miRNA, the fluorescence signal on the correspondingly encoded microspheres is significantly increased, while the fluorescence signal on other non-correspondingly encoded microspheres is almost negligible. Furthermore, this process exhibited good recovery and reproducibility in serum. The advantages of this method allow us to more conveniently obtain the expression profiles of multiple groups of TNBC-associated miRNAs, which is beneficial for the early detection of TNBC.
Uranium is the main fuel of nuclear power and elimination uranium from nuclear wastewater is significant both in environmental protection and fuel recycle. Here we report for the first time the synthesis of carbon dots/polyurethane (CDs/PU) composite materials for the photoinduced elimination of uranium from water. Irradiated with visible light, CDs/PU could eliminate uranium efficiently with the generation of (UO2)O2·2H2O as solid products in air. The further investigated mechanism showed that the addition of CDs/PU could produce more H2O2 under visible light, which reacted with uranyl ions to form (UO2)O2·2H2O. Importantly, the sponge-like CDs/PU could be easily removed from water with high reusability as the elimination efficiency remained above 95% after 5 cycles. CDs/PU also displayed good selectivity in the presence of other metal ions. Our work affords exciting strategies for developing photocatalysts and eliminating uranium from water.
Herein, copper-catalyzed 1,4-protosilylation and 1,4-protoborylation of enynic orthoesters have been developed. The enynic orthoesters as precursors of unstable enynic esters were applied to produce the functionalized 2, 3-allenoate products. Meanwhile, the asymmetric 1,4-protosilylation of enynic orthoesters with PhMe2Si-Bpin was also studied. The chiral monopyridine imidazoline ligand was efficient to provide the asymmetric 1,4-protosilylation products with high enantioselectivity.
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