Latest ArticlesThe rechargeable Li-O2 battery endowed with high theoretical specific energy density has sparked intense research interest as a promising energy storage system. However, the intrinsic high activity of Li anode, especially to moisture, usually leads to inferior electrochemical performance of Li-O2 battery in humid environments, hindering its widespread application. To settle the trouble of poor moisture tolerance, fabricating a water-proof layer on the Li-metal anode could be an effective tactic. Herein, a facile strategy for constructing an ibuprofen-based protective layer on the Li anode has been proposed to realize highly rechargeable Li-O2 battery in humid atmosphere. Due to the in-situ reaction between ibuprofen reagent and metallic Li, the protective layer with a thickness of ~30 μm has been uniformly deposited on the surface of Li anode. Particularly, the protective layer, consisting of a large amount of hydrophobic alkyl group and benzene ring, can significantly resist water ingress and enhance the electrochemical stability of Li anode. As a result, the Li-O2 battery based on the protected Li anode achieves a long cycle life of 210 h (21 cycles at 1000 mAh/g, 200 mA/g) in highly moist atmosphere with relative humidity (RH) of 68%. This convenient and efficient strategy offers novel design concept of water-resistant metal anode, and paves the way to the promising future prospect for the high-energy Li-O2 battery implementing in the ambient atmosphere.
CRISPR/Cas system has been utilized to rationally manipulate intracellular genes, and it has been engineered as versatile and efficient gene editing tools with precise site-specificity and excellent targeting ability for therapeutics, diagnostics, and bioimaging. Here, the evolution and application of CRISPR/Cas systems were sketched chronologically. Landmark works were exemplified to illustrate the design principles of CRISPR/Cas systems. Furthermore, the delivery vectors of CRISPR/Cas system especially DNA nanomaterials-based vectors were categorized and illuminated. DNA nanomaterials are suitable for CRISPR/Cas system delivery via base pairing due to its sequence programmability and biocompatibility. Then the applications of CRISPR/Cas in diagnosis and genomic imaging were highlighted. At the end of the review, the challenges and opportunities of CRISPR/Cas systems were deeply discussed. We envision that the grant advances on CRISPR/Cas systems will promote the development of interdisciplinary fields in chemistry, biology and medicine.
Triple-negative breast cancer (TNBC) lacks specific regimens for targeted therapy. Repeat chemotherapy promotes the evolution of TNBC into highly chemo-resistant tumors that metastasize to multiple organs simultaneously. Herein, polyacrylic acid-coated ultrasmall superparamagnetic iron-oxide nanoparticles (PAA@IONs) and dual-targeting doxorubicin liposomes achieved chemo–immunotherapy through intermittent administration. They inhibited tumor-drug resistance and multiorgan-specific metastasis significantly by targeting tumors and the microenvironment. We deciphered an immunosuppressive pre-metastatic niche and discovered that PAA@IONs could target tumors, tumor-draining lymph nodes (TDLNs), the liver, bone, and lungs. They promoted the polarization of macrophages into M1 macrophages in these organs and tissues. This action remodeled the immunosuppressive microenvironment and induced a sustained immune response, thereby reducing organ-specific metastasis. Overcoming the disadvantages of doxorubicin-induced cardiotoxicity as well as low tumor specificity, dual peptide-modified liposomes could target CD206 and CD13 simultaneously, and reverse chemo-resistance. These properties resulted in a significant decrease in the numbers of myeloid-derived suppressor cells (MDSCs) and cancer stem cells (CSCs) in the liver, lungs, and bone, thereby reducing protein expression of Ki-67 in TDLNs, and dramatically increasing the number of cluster of differentiation (CD)8+T cells and CD8+ T cell/T-regulatory-cell ratio in tumors and TDLNs (P < 0.0001). Compared with the control (P < 0.05 and P < 0.01, respectively) or free drug (P < 0.0001 and P < 0.01, respectively), multi-organ metastases were suppressed significantly, tumor-growth rate reduced, and survival prolonged. Our drug-delivery system overcame TNBC chemo-resistance and inhibited multiorgan-specific metastases. It circumvents the lack of effective therapeutic targets, the problem of patient selection due to a low mutation rate, and can simultaneously offer the possibility of avoiding surgery and considerable postoperative complications.
A palladium-catalyzed cascade cyclization of allenylethylene carbonates with 1,3-indandiones was developed, providing biologically interesting tetracyclic dihydrocyclopentaindenofuranone derivatives having three contiguous quaternary carbon centers in moderate to high yields with excellent diastereoselectivities. In this reaction, the allene moiety was fully fused into the cyclopentene ring.
Aromatic compounds such as phenols presented widely in coal chemical industry wastewater (CCW) render the treatment facing great challenge due to their biorefractory characteristics and potential risks to the environment and human health. Ozone-based advanced oxidation processes show promising for these pollutants removal, but the mineralization via ozonation alone is unsatisfactory and not cost-effective. Herein, a hybrid peroxi-coagulation/ozonation process (denoted as PCO) was developed using sacrificial iron plate as an anode and carbon black modified carbon felt as cathode in the presence of ozonation. An enhanced phenol removal of ~100% within 20 min and phenol mineralization of ~80% within 60 min were achieved with a low energy consumption of 0.35 kWh/g TOC. In this novel process, synergistic effect between ozonation and peroxi-coagulation was observed, and beside O3 direct oxidation, peroxone played a dominant role for phenol removal. In the PCO process, the hydrolyzed Fe species enhanced the generation of reactive oxygen species (ROS), while •OH was dominantly responsible for pollutant degradation. This process also illustrated high resistance to high ionic strength and better performance for TOC removal in real wastewater when compared with ozonation and peroxi-coagulation process. Therefore, this process is more cost-effective, being very promising for CCW treatment.
Metal/nucleophilic Lewis base dual catalysis has been recognized as a reliable and promising strategy for finishing ideal organic synthesis over the past decades. The new strategy can usually achieve some chemical reactions that cannot be realized by the traditionally mono-catalytic system, dramatically expanding the synthetic utility of chemical transformations by leveraging additional activation modes. Thus considerable progress has been made in the synthesis of a wide range of heterocyclic and biologically active compounds by using the combination of diversely metal/nucleophilic Lewis base dual catalysts, including metal/phosphine, metal/N-heterocyclic carbene (NHC) and metal/tertiary amine dual catalysis systems. In this review, we describe a comprehensive and updated advance of metal/nucleophilic Lewis base dual catalytic annualtion reactions, meanwhile, the related mechanism and the application of these annulation strategies in natural product total synthesis will be highlighted in detail.
Carbon dots (CDs), a new building unit, have been revolutionizing the fields of biomedicine, bioimaging, and optoelectronics with their excellent physical, chemical, and biological properties. However, the difficulty of preparing excitation-dependent full-spectrum fluorescent CDs has seriously hindered their further research in fluorescence emission mechanisms and biomedicine. Here, we report full-spectrum fluorescent CDs that exhibit controlled emission changes from purple (380 nm) to red (613 nm) at room temperature by changing the excitation wavelength, and the excitation dependence was closely related to the regulation of sp2 and sp3 hybrid carbon structures by β-cyclodextrin-related groups. In addition, by regulating the content of β-cyclodextrin, the optimal quantum yields of full-spectrum fluorescent CDs were 8.97%, 8.35%, 7.90%, 9.69% and 17.4% at the excitation wavelengths of 340, 350, 390, 410 and 540 nm, respectively. Due to their excellent biocompatibility and color tunability, full-spectrum fluorescent CDs emitted bright and steady purple, blue, green, yellow, and red fluorescence in MCF-7 cells. Moreover, we optimized the imaging conditions of CDs and mitochondrial-specific dyes; and realized the mitochondrial-targeted co-localization imaging of purple, blue and green fluorescence. After that, we also explored the effect of full-spectrum fluorescent CDs in vivo fluorescence imaging through the intratumorally, subcutaneously, and caudal vein, and found that full-spectrum fluorescent CDs had good fluorescence imaging ability in vivo.
With the rapid development of economy, industrial and agricultural pollutants have caused great damage to the ecological environment and the normal development of organisms, posing a serious threat to global public health. Therefore, rapid and sensitive detection of pollutants is very important for environmental safety and people’s health. A stable multi-response fluorescence sensor (RhB@1) with dual emission characteristics was constructed by embedding RhB guest molecules in Zn-MOF using a simple one-pot method. XRD, IR, XPS, Raman and other characterization methods were used to demonstrate the formation of composite materials. The sensor has two fluorescence emission peaks at 415 nm and 575 nm under the excitation of 316 nm. It has high sensitivity and low detection limit (7.94 and 7.82 nmol/L, respectively) in the detection of fluazinam (FLU) and Fe3+. The mechanism of fluorescence quenching may be due to the synergistic effect of IFE and PET. Outstandingly, when ascorbate acid (AA) was added to the quenching system of Fe3+ and RhB@1, its fluorescence gradually recovered, forming the unique “on-off-on” sensor. Therefore, RhB@1 has a fast fluorescence response and good stability, making it potentially useful in practical application and biosensors. More significantly, using Fe3+ and AA as chemical input signals, a binary intelligent logic gate device has been developed based on the “on-off-on” response mode of RhB@1, which extends the application of logic gate switching devices in the chemical field. In addition, a visual portable test paper with good selectivity and high sensitivity was developed, which can be used for rapid detection of FLU, showing its broad application prospect.
Peptide-drug conjugates (PDCs) composed of peptide, spacer and drug have gained extensive attention in the field of drug delivery owing to its precise control over the drug payload and architecture. However, the achievement of controllable and rapid drug release at targeted site by PDCs is still a great challenge for pharmaceutist. Herein, we introduced the histidine residue into PDCs to generate a supramolecular hydrogel via a pH-trigger strategy, which exhibited an autocatalytic effect to precisely tune drug release from PDCs hydrogel. Using indomethacin (Idm) as model drug, various PDCs (Y(Idm)EEH, Y(Idm)EEK and Y(Idm)EER) were synthesized and their self-assembling properties were investigated in terms of critical aggregation concentration (CAC), transmission electron microscopy (TEM) and rheometer. Introduction of histidine residue into PDCs presented a robust catalytic activity on the ester hydrolysis of p-nitrophenyl acetate in aqueous solution, as well conferred the autocatalytic capacity to hydrolyze the PDCs into active parent drug (Idm). Overall, we reported an autocatalytic activity of histidine residue to precisely tune drug release from PDCs hydrogels.
Regenerating spent graphite (SG) from retired lithium-ion batteries (LIBs) can effectively avoid resource waste. However, the technology is challenged by the impurity content and energy consumption. In this study, micro-expanded graphite (MEG) was synthesized by one-step oxidation method using waste LIBs anode graphite as material and perchloric acid as intercalation and oxidant agent. Then, its performance as a LIBs anode material were investigated as well as the greenhouse gas (GHG) emissions of the whole process were calculated. Perchloric acid was successfully embedded in the SG during the reaction, which effectively removed the impurities in the graphite. Defects introduced during intercalation and delamination, such as nanopores and intercrystalline cracks. Both provide additional space for Li ions during charging and discharging, thereby promoting capacity enhancement. The prepared MEG expresses a rate capability as high as 340.32 mAh/g at a current density of 0.1 C and still retains 81.73% of the capacity after 100 cycles at a current density of 1 C. Additionally, the GHG emissions of the synthesis process of this article and other literatures are compared. The results demonstrated that perchloric acid treatment process provides a low-carbon, time- and energy-saving approach for regenerated SG as battery grade material.
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