Latest ArticlesDeveloping novel emissive supramolecular assemblies with elegant architectures and tunable performance remains highly desirable yet challenging. Herein, we report the design and synthesis of several 9,10-bis(diphenylmethylene)-9,10-dihydroanthracene-based metal-organic assembles with aggregation-induced emission characteristics. Such assemblies feature intriguing thermochromic and mechanochromic properties, i.e., distinguishable fluorescence responses in terms of emission wavelength and intensity under variable temperatures and pressures. Moreover, these assemblies can serve as excellent fluorescent sensors for the detection of polysaccharide molecules. Due to the differentiated charge type and density, the assembles display distinct sensing mechanisms toward different polysaccharide molecules. This study provides novel perspectives for the synthesis of butterfly-like platinum(Ⅱ) supramolecular coordination complexes with multistimuli-responsiveness for polysaccharide sensing, which will facilitate the development of stimuli-responsive materials
Büchner reaction, as a unique type of expansive dearomatization, has become a practical strategy for the straightforward assembly of valuable functionalized cycloheptatrienes from ubiquitous aromatic precursors. Although the asymmetric version has been investigated since the early 1990s, enantioselective Büchner reaction is still limited by the catalyst type and substrate scope. This review aims to propose the limitation and possible development direction of this field by summarizing the evolution of catalytic asymmetric Büchner reaction, which is organized on the basis of intra- and intermolecular reactions. Considering the different metal carbene precursors, the reactions are further classified by carbene sources.
Identification of lymph nodes (LNs) is critical for studies of the structure, the role in disease development, and the efficacy of disease treatment. Carbonized polymer dots (CPDs) are expected to be potential LNs-targeted imaging agents due to their excellent properties with special structure, better photoluminescence (PL) and great biocompatibility. Herein, a red/near infrared (NIR) emission CPDs (RCPDs) with one and two-photon bioimaging based on citric acid (CA) and benzoylurea (BU) are prepared. Notably, the RCPDs are capable of targeting LNs for imaging. Lymphocyte homing has been demonstrated to be the cellular mechanism of RCPDs target LNs imaging. This work has developed a new nanomaterial for targeted imaging of LNs, while the biological applications of CPDs have been expanded and deepened.
Highly selective conversion of methane (CH4) to methanol (CH3OH) is an emerging attractive but challenging process for future development of hydrogen economy, which requires efficient catalysts. Herein, we systematically explore the catalytic properties of Pt(111) overlayer on transition metal oxides (TMOs) for CH4 conversion by first principles calculations. The Pt(111) monolayer supported by Ce-terminated CeO2(111) substrate exhibits high activity and selectivity for CH4 conversion to CH3OH, with the kinetic barrier of rate-limiting step of 1.05 eV. Intriguingly, the surface activity of Pt overlayer is governed by its d-band center relative to the energy of bonding states of adsorbed molecules, which in turn depends on the number of charge transfer between Pt(111) monolayer and underlying TMOs substrates. These results provide useful insights in the design of metal overlayers as catalysts with high-ultra performance and atomic utilization.
A continuous flow bioreactor was operated for 300 days to investigate partial nitritation (PN) of mature landfill leachate, establishing the long-term performance of the system in terms of the microbial community composition, evolution, and interactions. The stable operation phase (31–300 d) began after a 30 days of start-up period, reaching an average nitrite accumulation ratio (NAR) of 94.43% and a ratio of nitrite nitrogen to ammonia nitrogen (NO2−-N/NH4+-N) of 1.16. Some fulvic-like and humic-like compounds and proteins were effectively degraded in anaerobic and anoxic tanks, which was consistent with the corresponding abundance of methanogens and syntrophic bacteria in the anaerobic tank, and organic matter degrading bacteria in the anoxic tank. The ammonia-oxidizing bacteria (AOB) Nitrosomonas was found to be the key functional bacteria, exhibiting an increase in abundance from 0.27% to 6.38%, due to its collaborative interactions with organic matter degrading bacteria. In-situ inhibition of nitrite-oxidizing bacteria (NOB) was achieved using a combination of free ammonia (FA) and free nitrous acid (FNA), low dissolved oxygen (DO) with fewer bioavailable organics conditions were employed to maintain stable PN and a specific ratio of NO2−-N/NH4+-N, without an adverse impact on AOB. The synergistic relationships between AOB and both denitrifying bacteria and organic matter degrading bacteria, were found to contribute to the enhanced PN performance and microbial community structure stability. These findings provide a theoretical guidance for the effective application of PN-Anammox for mature landfill leachate treatment.
On-tissue chemical derivatization (OTCD) effectively enhances ionization efficiency of low abundant and poorly ionized functional molecules to improve detection sensitivity and coverage of mass spectrometry imaging (MSI). Combination OTCD and MSI provides a novel strategy for visualizing previously undisclosed metabolic heterogeneity in tumor. Herein, we present a method to visualize heterogeneous metabolism of oxylipins within tumor by coupling OTCD with airflow-assisted desorption electrospray ionization (AFADESI)-MSI. Taking Girard's P as a derivatization reagent, easily ionized hydrazide and quaternary amine groups were introduced into the structure of carbonyl metabolites via condensation reaction. Oxylipins, including 127 fatty aldehydes (FALs) and 71 oxo fatty acids (FAs), were detected and imaged in esophageal cancer xenograft with AFADESI-MSI after OTCD. Then t-distributed stochastic neighbor embedding and random forest were exploited to precisely locate the distribution of oxylipins in heterogeneous tumor tissue. With this method, we surprisingly found almost all FALs and oxo FAs significantly accumulated in the core region of tumor, and exhibited a gradual increase trend in tumor over time. These results reveal spatiotemporal heterogeneity of oxylipins in tumor progression, highlighting the value of OTCD combined with MSI to gain deeper insights into understanding tumor metabolism.
The solid electrolyte interphase (SEI), a passivation film covering the electrode surface, is crucial to the lifetime and efficiency of the lithium-ion (Li-ion) battery. Understanding the Li-ion diffusion mechanism within possible components in the mosaic-structured SEI is an essential step to improve the Li-ion conductivity and thus the battery performance. Here, we investigate the Li-ion diffusion mechanism within three amorphous SEI components (i.e., the inorganic inner layer, organic outer layer, and their mixture with 1:1 molar ratio) via ab initio molecular dynamic (AIMD) simulations. Our simulations show that the Li-ion diffusion coefficient in the inorganic layer is two orders of magnitude faster than that in the organic layer. Therefore, the inorganic layer makes a major contribution to the Li-ion diffusion. Furthermore, we find that the Li-ion diffusivity in the organic layer decreases slightly with the increase of the carbon chain from the methyl to ethyl owing to the steric hindrance induced by large groups. Overall, our current work unravels the Li-ion diffusion mechanism, and provides an atomic-scale insight for the understanding of the Li-ion transport in the SEI components.
Rhodium (Rh) has received widespread attention in fundamental catalytic research and numerous industrial catalytic applications. Compared to homogeneous catalysts, Rh-based nanomaterials as heterogeneous catalysts are much easier to separate and collect after usage, making them more suitable for commercial use. To this purpose, there has been a constant demand in constructing stable and highly active Rh-based nanomaterials. In contrast to Rh-based solid solutions with a random distribution of metallic atoms in the lattice, Rh-based intermetallic compounds (IMCs) with a fixed stoichiometric ratio and an ordered atomic arrangement can ensure the homogenous distribution of active sites and structural stability in the catalytic process. In this review, we concentrate on the fabrication of Rh-based IMCs for catalytic applications. Various synthetic methods and protocols for the controlled preparation of Rh-based IMC are illustrated. Meanwhile, the catalytic applications and corresponding catalytic mechanisms are discussed. In addition, personal perspectives about the remaining challenges and prospects in this field are provided. We believe this review will be useful in directing the development of Rh-based IMC catalysts for heterogeneous catalysis.
3D microgels with various mechanical properties have been important platforms tumor metastasis analysis, and widely adjustable stiffness is crucial for deeper researches. Herein, by mixing biodegradable polylactic acid (PLA) nanofibers in the modified alginate with different concentrations of Ca2+, we significantly enhance the stiffness range of microgels while retaining the pore size, which provides bionic microenvironment for tumor analysis. As a proof of concept, we simulated the mechanical characteristics of breast tumors by encapsulating cells in 3D microgels with diverse stiffness, and analyzed cellular behaviors of two typical breast cancer cell lines: MCF-7 and SUM-159. Results showed that with the addition of 2.0% (w/v) PLA short nanofibers, the Young's modulus of modified alginate increased more than three-fold. Besides preserving high survival and proliferation rates, both cells also displayed stronger migration ability in soft microgel spheres, where RT-qPCR analysis revealed the underlying changes at the genetic level. This systematic study demonstrated our method is powerful for creating widely adjustable 3D mechanical microenvironment, and the results of cellular behavior analysis shows its promising application prospects in tumorigenesis and progression.
Chemotherapy combined with photodynamic therapy has emerged as a promising strategy for cancer treatment. However, simultaneously delivering chemotherapeutic drugs and photosensitizers and precisely adjusting the ratio of the two components as needed remains a challengeable task. Herein, novel supramolecular nanoparticles (donated as BODIPY-CPT-NPs) for chemo-photodynamic combination cancer therapy are constructed from a glutathione-responsive camptothecin-based prodrug, BODIPY photosensitizer, and dimacrocyclic host molecule through orthogonal host-guest recognitions and co-assembly. With this strategy, the ratio of prodrugs and photosensitizers in nanoparticles can be easily and precisely controlled as needed. Benefiting from the strong host-guest interactions and stable self-assembly, the nanoparticles exhibit excellent stability and photobleaching resistance. Furthermore, camptothecin can be released from nanoparticles for chemotherapy in the presence of reduction agent and single oxygen can be efficiently generated for PDT with light irradiation. The combined effects of the BODIPY-CPT-NPs have been verified in CT26 and HeLa cancer cells.
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