Latest ArticlesThe chemical investigation into the EtOAc extract of the deep-sea-derived fungus Penicillium citrinum W22 yielded three unprecedented citrinin dimers, neo-Dicitrinols A–C (1–3) and a known one, penicitrinone A (4). Their structures were elucidated by extensive analysis of spectroscopic data, electronic circular dichroism (ECD) calculation, X-ray diffraction, and biogenetic consideration. neo-Dicitrinols A–C (1–3), bearing a tetramic acid unit, represent the first example of citrinin analogues as hybrid polyketide synthase-nonribosomal peptide synthase (PKS-NRPS) products. neo-Dicitrinol C (3) significantly inhibited renin-angiotensin system-selective lethal 3 (RSL3)-induced ferroptosis with a half maximal effective concentration (EC50) value of 21.6 µmol/L.
2-Deoxy-α-C-Glycosides are a significant class of carbohydrates found in numerous bioactive molecules and medicines. Developing a concise strategy for the assembly of these α-configured C-glycosides is crucial in the field of carbohydrate chemistry. However, current methods are restricted to the utilization of glycosyl radical precursors, which are required for pre-syntheses. Herein, we present a novel approach for the synthesis of 2-deoxy-α-C-glycosides using a nickel-catalyzed stereoselective coupling reaction with commercially available glycals. Notably, this method circumvents the preparation for diverse glycosyl radical precursors. The developed protocol exhibits a broad substrate scope and remarkable stereoselectivity under mild reaction conditions. Furthermore, the raw materials required for this process are readily accessible, eliminating the necessity for pre-functionalization modifications of the glycosyl substrates and ensuring high atomic economy.
Aromatic aldehydes are the most fundamentally important compounds used in organic synthesis. The development of new synthetic methods for introduction of a formyl group into an organic scaffold is highly desirable. In this report, a nickel-catalyzed reductive coupling between aryl halides and α–chloro N-methoxyphthalimide has been documented for the synthesis of a diverse array of aromatic aldehydes. Because of mild reductive coupling conditions, excellent functional group tolerance, especially for substrates containing free -OH and -NH2, was observed. Due to the simple operation mode, a large library of aromatic aldehydes can be quickly constructed by this process. Moreover, the present protocol is amenable for late-stage functionalization of bioactive compound. A combined computational and experimental investigation suggested the reaction may undergo a reaction mechanism of active Ni(I) catalyst formation and the formation of key formyl radical intermediate under zinc reductive conditions.
Ensuring the timely and precise monitoring of severe liver diseases is crucial for guiding effective therapies and significantly extending overall quality of life. However, this remains a worldwide challenge, given the high incidence rate and the presence of strong confounding clinical symptoms. Herein, we applied a convenient and high-yield method to prepare the magnetic mesoporous carbon (MMC-Fe), guided by a composite of resol and triblock copolymer. With the combination of MMC-Fe, high-throughput mass spectrometry, and a simple machine learning algorithm, we extracted N-glycan profiles from various serum samples, including healthy controls, liver cirrhosis, and liver cancer, and from which we screened specific N-glycans. Specifically, the selected N-glycans demonstrate exceptional performance with area under the curve (AUC) values ranging from 0.948 to 0.993 for the detection of liver diseases, including alpha fetoprotein (AFP)-negative liver cancer. Among them, five N-glycans holds potential in monitoring distinctions between liver cirrhosis and AFP-negative liver cancer (AUC values of 0.827–0.842). This study is expected to promote the glycan-based precise monitoring of diseases, not limited to liver disease.
The combination of diagnostic and therapeutic agents in the form of theranostic platforms to enhance tumor therapeutic efficacy is receiving increasing attention in recent years. However, simultaneous encapsulation, embedding or conjugation of various agents to traditional theranostic nanocarriers always require intricate synthetic process. Herein, a supramolecular drug-drug self-delivery nanosystem (DSDN) based on a newly developed aggregation-induced emission (AIE) photosensitizer (CBTM) and an anti-tumor tyroservaltide (YSV) was constructed for near-infrared (NIR) fluorescence imaging-guided photodynamic/chemotherapy of tumor. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) confirmed that YSV and CBTM could co-assemble into YSV/CBTM nanoparticles, with regular round-shape morphology and homogeneous size. Inspiringly, YSV/CBTM nanoparticles could effectively overcome the aggregation-caused quenching (ACQ) effect, and enter CT26 tumor cells with a high NIR fluorescence emission, allowing preoperative diagnosis. Meanwhile, the as-prepared YSV/CBTM could efficiently generate reactive oxygen species (ROS) under NIR light irradiation, exhibiting photodynamic ablation of tumor cells. More importantly, the peptide drug of YSV not only improved the availability of CBTM nanoparticles, but also served as a toxic adjuvant to enhance the photodynamic therapy (PDT) efficacy of CBTM. In vitro and in vivo assays revealed that most of colorectal tumor cells and tumor tissues were thoroughly ablated by photodynamic-chemotherapy integrated nanoparticles, resulting in longer survival of tumor-bearing mice. Regarding the advantages of the YSV/CBTM nanosystem, we believe this research could offer valuable guidance for the design of nanodrugs with high performance for cancer theranostics.
Owing to the high spatiotemporal resolution, the second near-infrared (NIR-Ⅱ) imaging window can provide high imaging contrast with diminished tissue autofluorescence and suppressed photon scattering to pinpoint the locations for tumor surgery. Due to the unique optical properties and excellent fluorescence performance, quantum dots (QDs) are regarded as ideal nanoprobes for fluorescence-guided surgery (FGS). Moreover, QDs can be excited by a variety of light sources owing to the continuous and wide absorption ranges. Herein, light-emitting diode (LED) was used as the excitation source of QDs-based nanoprobes to realize FGS of tumor with high resolution. Since the LED light could irradiate a large region with consistent light intensity, signal distortion at the edge of imaging field was avoided. The signal intensity of the view edges under LED excitation can be improved by about 5 times compared to laser excitation. Therefore, more micro-vessels and smaller tumors (Vtumor < 5 mm2) could be detected, thus providing more precise guidance for tumor resection surgery.
Bacterial endotoxin (a type of lipopolysaccharide, LPS) that acts as the strongest immune stimulant exhibits high toxicity to human health. The golden standard detection methods rely heavily on the use of a large amount of tachypleus amebocyte lysate (TAL) reagents, extracted from the unique blue blood of legally protected horseshoe crabs. Herein, a cost-effective distance-based lateral flow (D-LAF) sensor is demonstrated for the first time based on the coagulation cascade process of TAL induced by endotoxin, which causes the generation of gel-state TAL. The gelation process can increase the amount of trapped water molecules and shorten the lateral flow distance of the remaining free water on the pH paper. The water flow distance is directly correlated to the concentration of endotoxin. Noteworthy, the D-LAF sensor allows the detection of endotoxin with the reduced dosage of TAL reagents than the golden standard detection methods. The detection limit of endotoxin is calculated to be 0.0742 EU/mL. This method can be applied to the detection of endotoxin in real samples such as household water and clinical injection solution with excellent performance comparable to the commercial ELISA kit.
The carboxylation of readily available organo halides with CO2 represents a practical strategy to afford valuable carboxylic acids. However, efficient carboxylation of inexpensive unactivated alkyl chlorides is still underdeveloped. Herein, we report the electro-reductive carboxylation of CCl bonds in unactivated chlorides and polyvinyl chloride with CO2. A variety of alkyl carboxylic acids are obtained in moderate to good yields under mild conditions with high chemoselectivity. Importantly, the utility of this electro-reductive carboxylation is demonstrated with great potential in polyvinyl chloride (PVC) upgrading, which could convert discarded PVC from hydrophobic to hydrophilic functional products. Mechanistic experiments support the successive single electron reduction of unactivated chlorides to generate alkyl anion species and following nucleophilic attack on CO2 to give desired products.
BiVO4 is a promising semiconducting photoanode for photoelectrochemical (PEC) water splitting due to its suitable bandgap. However, the dissolution of V5+ and sluggish reaction kinetics at the surface in the oxygen evolution reaction (OER) limit its applications. Herein, we report a convenient strategy to change the microenvironment by adding Fe(Ⅲ) into the electrolyte. During the PEC process, Fe(Ⅲ) ions not only improve the current density, but also show excellent stability toward BiVO4. Consequently, the current increases by more than 1.7 times compared to that without Fe(Ⅲ). Photoelectrochemical, morphological, and structural characterizations reveal that the FeOOH co-catalyst produced in situ on the BiVO4 photoanode by cyclical formation of the intermediates at the electrode/electrolyte interface during OER accelerates the OER kinetics and prevents photo-corrosion by suppressing the dissolution of V5+. The results reveal a new strategy for the multifunctional modification of photoanodes for efficient solar conversion.
Higher initial (de)hydrogenation temperature and sluggish kinetics are the main bottlenecks to develop Mg-based hydrogen storage alloys with high hydrogen capacity. One of the effective methods of solving these problems is introducing additives to enhance (de)hydrogenation kinetics and decrease particle sizes to lower (de)hydrogenation temperatures. In this work, Mg85-Ni10-La4.5-Y0.5 alloy doped with Cu@C nanoparticles is prepared, which could enhance (de)hydrogenation kinetics via introducing Cu nanoparticles as a catalyst and reduce the alloy particle sizes via acting as a grinding agent to lower (de)hydrogenation temperature. The results indicate the dehydrogenation temperature of the modified Mg85-Ni10-La4.5-Y0.5 composite could be decreased to 308.5 ℃, absorb 4.73 wt% H2 at 220 ℃ within 1 min and release 5.01 wt% H2 within 4 min at 300 ℃. Moreover, the capacity retention could be maintained around 98.8% after 10 cycles at 300 ℃, superior than those of Mg85-Ni10-La4.5-Y0.5 and milled-Mg85-Ni10-La4.5-Y0.5. DFT results and characterizations suggest that in-situ formed Mg2Cu could accelerate the dissociation of Mg-H bonds and the presence of amorphous carbon in Mg-Ni-La-Y-Cu system will further synergistically improve the (de)hydrogenation kinetics of Mg85-Ni10-La4.5-Y0.5. Reduced particle sizes under the aid of carbon frameworks also help introduce boundaries of the particles and shorten hydrogen diffusion pathways.