Excited-Multimer Mediated Supramolecular Upconversion on Multicomponent Lanthanide-Organic Assemblies.

Upconversion (UC) is a fascinating anti-Stokes-like optical process with promising applications in diverse fields. However, known UC mechanisms are mainly based on direct energy transfer between metal ions, which constrains the designability and tunability of the structures and properties. Here, we synthesize two types of Ln8L12-type (Ln for lanthanide ion; L for organic ligand L1 or L2R/S) lanthanide-organic complexes with assembly induced excited-multimer states. The Yb8(L2R/S)12 assembly exhibits upconverted multimer green fluorescence under 980 nm excitation through a cooperative sensitization process. Furthermore, upconverted red emission from Eu3+ on the heterometallic (Yb/Eu)8L12 assemblies is also realized via excited-multimer mediated energy relay. Our findings demonstrate a new strategy for designing UC materials, which is crucial for exploiting photofunctions of multicomponent lanthanide-organic complexes.

Guest-Driven Self-Assembly and Chiral Induction of Photofunctional Lanthanide Tetrahedral Cages.

Chiral luminescent lanthanide-organic cages have many potential applications in enantioselective recognition, sensing, and asymmetric catalysis. However, due to the paucity of structures and their limited cavities, host-guest chemistry with lanthanide-organic cages has remained elusive so far. Herein, we report a guest-driven self-assembly and chiral induction approach for the construction of otherwise inaccessible Ln4L4-type (Ln = lanthanide ions, i.e., EuIII, TbIII; L = ligand) tetrahedral hosts. Single crystal analyses on a series of host-guest complexes reveal remarkable guest-adaptive cavity breathing on the tetrahedral cages, reflecting the advantage of the variation tolerance on coordination geometry of the f-elements. Meanwhile, noncovalent confinement of pyrene within the lanthanide cage not only leads to diminishment of its excimer emission but also facilitates guest to host energy transfer, opening up a new sensitization window for the lanthanide luminescence on the cage. Moreover, stereoselective self-assembly of either Λ4- or Δ4- type Eu4L4 cages has been realized via chiral induction with R/S-BINOL or R/S-SPOL templates, as confirmed by NMR, circular dichroism (CD), and circularly polarized luminescence (CPL) with high dissymmetry factors (glum) up to ±0.125.

Cytotoxin-associated gene A (CagA) promotes aortic endothelial inflammation and accelerates atherosclerosis through the NLRP3/caspase-1/IL-1ß axis.

Atherosclerosis is a chronic inflammatory disease. Pathophysiological similarities between chronic infections and atherosclerosis triggered interests between these conditions. The seroepidemiological study showed that Helicobacter pylori strains that express cytotoxin-associated gene A (CagA), an oncoprotein and a major virulence factor, was positively correlated with atherosclerosis and related clinical events. Nevertheless, the underlying mechanism is poorly understood. In this study, the seroprevalence of infection by H. pylori and by strains express CagA assessed by enzyme-linked immunosorbent assay (ELISA) showed that the prevalence of CagA strains rather than H. pylori in patients was positively correlated with atherogenesis. Correspondingly, we found that CagA augmented the growth of plaque of ApoE-/- mice in the early stage of atherosclerosis and promoted the expression of adhesion molecules and inflammatory cytokines in mouse aortic endothelial cells (MAECs). Mechanistically, both si-NLRP3 and si-IL-1ß mitigated the promoting effect of CagA on the inflammatory activation of HAECs. In vivo, the inhibition of NLRP3 by MCC950 significantly attenuated the promoting effect of CagA on plaque growth of ApoE-/- mice. We also propose NLRP3 as a potential therapeutic target for CagA-positive H. pylori infection-related atherosclerosis and emphasize the importance of inflammation in atherosclerosis pathology.

Hexameric Lanthanide-Organic Capsules with Tertiary Structure and Emergent Functions.

Biological macromolecules always function through a collective behavior of the aggregated constituents, which usually are self-assembled together via noncovalent interactions. Likewise, artificial supramolecular assemblies, whose properties and functions are mainly derived from their primary and secondary structures, may also aggregate into high-order architectures with emergent functions not available on the individual components. Here we report the first example of an insulin-like hexamerization of lanthanide triple helicates toward a 4 nm diameter hexameric capsule via consecutive metal-directed and anion-directed assembly processes. Hierarchical chiral-sorting self-assembly endows hexamers with aggregation-induced stability and emission enhancement. Furthermore, emergent guest-encapsulation function and enantioselectivity toward terpene drugs have been realized in the late-formed central cavity of the hexamers. This study not only provides a feasible strategy for constructing sophisticated and multifunctional lanthanide-organic materials but also sheds some light on the self-assembly processes in nature.

Coordination-Assembly of Lanthanide Supramolecular Hydrogels with Luminescent Multi-stimulus Response.

Luminescent supramolecular hydrogels have shown extensive potential for a variety of applications due to their unique optical properties and biocompatibility. Coordination self-assembly provides a promising strategy for the preparation of supramolecular hydrogels. In this contribution, a series of luminescent lanthanide (Ln) supramolecular hydrogels HG-Ln2nL3n1/2 are synthesized by coordination self-assembly of Ln ions and V shaped bis-tetradentate ligands (H4L1 and H4L2) with different bent angles (∠B). Two rigid conjugated ligands H4L1 and H4L2 with bent angles (∠B ≈ 150°) featuring a 2,6-pyridine bitetrazolate chelating moiety were designed and synthesized, which generated hydrogels via the deprotonation self-assembly with lanthanide ions. Characteristic Eu3+ and Yb3+ emissions were realized in the corresponding hydrogels, with intriguing multi-stimulus response behaviors. The luminescence of the HG-Eu2nL3n1 hydrogel can be enhanced or quenched when stimulated by diverse metal ions, attributed to the replacement of the coordinated lanthanide ions and changes in the intersystem crossing efficiency of the ligand. Furthermore, pH-responsive emission of the HG-Eu2nL3n1 hydrogel has also been observed. Our work provides potential strategies for the design of next-generation smart responsive hydrogel materials with variable structures.

Self-Assembly of Lanthanide-Covalent Organic Polyhedra: Chameleonic Luminescence and Efficient Catalysis.

A series of multinuclear lanthanide-covalent organic polyhedra (LnCOPs), including pillar-typed triangular prisms 1-Ln3 and tetrahedra 2-Ln4 (Ln = LaIII, SmIII, EuIII), have been constructed for the first time, through either one-pot subcomponent self-assembly or postassembly metalation. In contrast to the known tetrahedral cages based on transition metals, the pillar-typed polyhedra were favored from the same organic components in the presence of lanthanides. Besides this, facile transmetalations between the 1-Ln3 polyhedra endow cascade chameleonic luminescence. Meanwhile, the open metal sites and pendent amine groups on 1-Ln3 enable these polyhedra to catalyze the Henry reaction efficiently.

Fine-Tuned Visible and Near-Infrared Luminescence on Self-Assembled Lanthanide-Organic Tetrahedral Cages with Triazole-Based Chelates.

The construction of well-defined lanthanide complexes emitting in both the visible and near-infrared regions is of great importance due to their widespread applications in phosphors, light-emitting diodes, biosensors/probes, optical communications, etc. In comparison to the well-known mononuclear and dinuclear lanthanide complexes, multinuclear lanthanide supramolecular edifices with bright luminescence are still scarce. Herein, we report the coordination self-assembly of strongly luminescent lanthanide-organic tetrahedral Ln4L4 cages with a series of tris(tridentate) ligands based on the triazole chelates. Among them, the new ligand L3 with triazole-pyridine-triazole (TPT) chelates manifests an excellent sensitization toward all of the lanthanide ions (Ln = Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb) that emit in both the visible and near-infrared regions, with a record luminescent quantum yield for Tb4(L3)4 (Φ = 82%) being obtained. In contrast, ligands with amido-pyridine-triazole (APT) or TPA chelates show much weaker sensitization ability. Energy levels for all ligands were measured, and TD-DFT calculations were employed to shed light on the sensitization mechanism. Finally, white-light emission systems formed by combining the desired luminescent compounds have been demonstrated. Our strongly luminescent LOPs provide new candidates for photochemical supramolecular devices.

Self-Assembled Bright Luminescent Lanthanide-Organic Polyhedra for Ratiometric Temperature Sensing.

Luminescent lanthanide-containing compounds have a lot of stimulating applications. However, the fine-tuning of the optical properties of multi-nuclear lanthanide edifices is still a big challenge. We report here the coordination self-assembly of a group of bright luminescent lanthanide organic polyhedra (LOPs) with record high emission quantum yields, by using two fully-conjugated ligands featuring the triazole-pyridine-amido (tpa) chelating moiety, easily-accessible from the "Click" reaction. The self-assembled LOPs are characterized by NMR spectroscopy, high-resolution ESI-TOF-MS, and X-ray crystallography. Interestingly, inter-metal energy transfer (ET) is confirmed on the mixed-lanthanide polyhedral molecules, though the metal centers are separated nearly 2 nm apart. A feasible ratiometric luminescent thermometer, with work range from cryogenic to physiological temperatures, has been demonstrated with the mixed Eu/Tb LOPs. We envisage these molecular-level bright luminescent LOPs have great application potential in displaying, labelling/imaging, up-conversion materials etc.

Self-Assembly of a Tetraphenylethylene-Based Capsule Showing Both Aggregation- and Encapsulation-Induced Emission Properties.

Functional molecular capsules have attracted a lot of attention in recent years because of their potential applications as chemosensors, catalysis, drug carriers, and so on. We report here the coordination-directed self-assembly of a fluorescent-lantern-type molecular capsule from four tetraphenylethylene-based ditopic ligands and two square-planar palladium(II) ions. The capsule has been thoroughly characterized by UV-vis, 1D/2D NMR, electrospray ionization time-of-flight mass spectrometry, and single-crystal X-ray diffraction studies. The aggregation-induced emission performance of the capsule has been studied by tuning the ratio of mixed solvents. Moreover, with an open cavity, the fluorescence of the capsule also displays anion sensitivity, with the best turn-on responsiveness observed for HCO3-, demonstrating for the first time an encapsulation-induced emission property.

Hierarchical Self-Assembly and Chiroptical Studies of Luminescent 4d-4f Cages.

Multinuclear lanthanide-containing supramolecular cages have received increasing attention recently because of their unique electroptical and magnetic properties. Here we report the hierarchical self-assembly and chiroptical studies of a group of 4d-4f heterometallic cages synthesized from a preformed dimetalloligand [(bpy)2Pd212]2+ (2) (bpy = 2,2-bipyridine) and a variety of trivalent lanthanide ions (Ln = NdIII, EuIII, YbIII). The programmable self-assembly process leading to the trigonal bipyramidal cages formulated as {Ln2[(bpy)2Pd212]3}12+ (3) has been confirmed by one- and two-dimensional NMR, electro-spray-ionization time-of-flight mass-spectroscopy, and in one typical case by single-crystal X-ray diffraction studies. Circular dichroism and circular polarized luminescence spectra confirmed the strict control of stereoselectivity on the heterometallic cages, dictated by the chiral amide groups on the ligands. Excitation (up to 420 nm) on the dipalladium chromophores on these cages leads to the characteristic lanthanide luminescence at both the visible and the near-infrared regions, depending on the lanthanide ions used. Through the assembly-disassembly process, luminescent turn-off sensing toward penicillin among several widely used antibiotics has also been demonstrated with the Europium cage, featuring a limit of detection as low as 0.88 ppb (S/N = 3). Our results pave the way for the construction of chiral 4d-4f supramolecular cages which may find potential applications in luminescent sensing and/or labeling reagents.

Enhancement of the immunogenicity of a porcine circovirus type 2 DNA vaccine by a recombinant plasmid coexpressing capsid protein and porcine interleukin-6 in mice.

The development of effective vaccines against porcine circovirus type 2 (PCV2) has been accepted as an important strategy in the prophylaxis of post-weaning multisystemic wasting syndrome; a DNA vaccine expressing the major immunogenic capsid (Cap) protein of PCV2 is considered to be a promising candidate. However, DNA vaccines usually induce weak immune responses. In this study, it was found that the efficacy of a DNA vaccine expressing Cap protein was improved by simultaneous expression of porcine IL-6. A plasmid (pIRES-ORF2/IL6) separately expressing both Cap protein and porcine IL-6 was constructed and compared with another plasmid (pIRES-ORF2) expressing Cap protein for its potential to induce PCV2-specific immune responses. Mice were vaccinated i.m. twice at 3 week intervals and the induced humoral and cellular responses evaluated. All animals vaccinated with pIRES-ORF2/IL6 and pIRES-ORF2 developed specific anti-PCV2 antibodies (according to enzyme-linked immunosorbent assay) and a T lymphocyte proliferation response. The percentages of CD3(+), CD3(+)CD8(+), and CD3(+)CD4(+) subgroups of peripheral blood T-lymphocytes were significantly higher in mice immunized with pIRES-ORF2/IL6 than in those that had received pIRES-ORF2. After challenge with the virulent PCV2 Wuzhi isolate, mice vaccinated with pIRES-ORF2/IL6 had significantly less viral replication than those vaccinated with pIRES-ORF2, suggesting that the protective immunity induced by pIRES-ORF2/IL6 is superior to that induced by pIRES-ORF2.

Expression of bioactive porcine interferon-alpha in Lactobacillus casei.

In this study, we constructed an expression cassette containing the inducible lac promoter and the secretion signal from an S-layer protein of Lactobacillus brevis for the expression of porcine interferon-alpha (IFN-α) in Lactobacillus casei (Lb. casei). Reverse-transcriptase PCR verified the presence of porcine IFN-α mRNA in the recombinant Lb. casei. The porcine IFN-α protein expressed in the recombinant Lb. casei was identified by both Western blot analysis and ELISA. We used various pH values and induction times to optimize the yield of IFN-α, and found that induction with 0.8% lactose for 16 h under anaerobic conditions produced the highest concentrations of IFN-α. Furthermore, the activity of porcine IFN-α in the cultural supernatant was evaluated on ST cells infected with pseudorabies virus. The results revealed that porcine IFN-α inhibited virus replication in vitro. The findings of our study indicate that recombinant Lb. casei producing porcine IFN-α has great potential for use as a novel oral antiviral agent in animal healthcare.

[Study on supercritical CO2 extraction of xiaoyaosan and its GC-MS fingerprint].

To determine the optimum conditions of supercritical CO2 extraction of Xiaoyaosan, and establish its fingerprint by gas chromatography-mass spectrometry (GC-MS), the yield of extract were investigated, an orthogonal test was used to quantify the effects of extraction temperature, pressure, CO2 flow rate and time, and fingerprint analysis of different batches of extracts were by GC-MS. The optimal extraction conditions were determined as follows: extraction pressure 20 MPa, extraction temperature 50 degrees C, CO2 flow rate 25 kg x h(-1), extraction time 3 h, and average yield 2.2%. The GC-MS fingerprint was established and 27 common peaks were found, whose contents add up to 81.89% of the total peak area. Among them, 21 compounds were identified, accounting for 53.20% of the total extract. The extraction process is reasonable and favorable for industrial production. The GC-MS method is accurate, reliable, reproducible, and can be used for quality control of supercritical CO2 extract from Xiaoyaosan.

[Anti-depressant effect and mechanism of supercritical CO2 extract from Compound Chaigui Fang].

The tail suspension test (TST), forced swimming test (FST) and chronic unpredictable mild stress (CUMS) model were used to evaluate the anti-depressant effect of supercritical CO2 extract from Compound Chaigui Fang (FFCGF). A nuclear magnetic resonance (NMR)-based metabonomics combined with multivariate statistical analysis was performed to explore the mechanism of FFCGF. Rats were conducted by CUMS procedure for 28 days and drugs were administrated at the same time. The body weight, sucrose preference, crossings and rearings in open-field tests were evaluated and the urine was collected simultaneously. The metabonomic profiles of rats' urine were analyzed by NMR and potential biomarkers were searched by multivariate statistical analysis. The results showed that administration of FFCGF significantly decreasing the immobility time in FST and TST and improving rats' body weight, sucrose preference, crossings and rearings in CUMS, which were indication that the anti-depressant effect of FFCGF was abvious. Significant differences in the metabolic profile of the CUMS treated group and the control group were observed, which were consistent with the results of behavioral tests. Decreased levels of acetic acid, succinic acid, 2-oxidation glutaric acid and citric acid and increased glycine and pyruvic acid in urine were significantly affected by the CUMS procedure and the 6 biomarkers were reversed evidently after administration of FFCGF. These changes were suggestion that the anti-depressant mechanism of FFCGF was associated with energy metabolism, lipid metabolism and amino acid metabolism.

Subtle adjustments for constructing multi-nuclear luminescent lanthanide organic polyhedra with triazole-based chelates.

Controlled self-assembly of predetermined multi-nuclear lanthanide organic polyhedra (LOPs) still presents a challenge, primarily due to the unpredictable coordination numbers and labile coordination geometries of lanthanide ions. In this study, through introducing triazole-based chelates to increase the chelating angle of C2-symmetric linear ligands and stabilize the coordination geometry of Eu(III) centers, M4L6-type (M = EuIII, L = ligand) tetrahedra were efficiently synthesized, especially a biphenyl-bridged ligand which is well known to form M2L3-type helicates. A series of LOPs were formed and characterized by high-resolution electrospray ionization time-of-flight mass spectroscopy (ESI-TOF-MS) and X-ray crystallography. Moreover, the europium complexes exhibit bright emission (luminescence quantum yield up to 42.4%) and circularly polarized luminescence properties (|glum| up to 4.5 × 10-2). This study provides a feasible strategy for constructing multi-nuclear luminescent LOPs towards potential applications.

Hierarchical subcomponent self-assembly of covalent triple-stranded complexes with 3d-4f vertices: luminescence and magnetic properties.

Well-defined 3d-4f heterometallic supramolecular architectures have attracted attention because of their applications in the field of luminescence and magnetism. However, covalent metallo-supramolecular discrete complexes, decorated with hetero-metallic vertices, have never been reported because of the difficulties in design and control. Herein, we report a series of covalent metallo-supramolecular discrete complexes with 3d-4f vertices synthesized by hierarchical subcomponent self-assembly of tris(2-aminoethyl)amine, 2,6-diformyl-p-cresol, and lanthanide ions (Ln) with different amines and transition metal ions. The programmable self-assembly process results in the formation of triple-stranded hetero-metallic covalent organic discrete complexes, namely 3a-3c-(Ln, Zn) (Ln = SmIII, EuIII, DyIII, YbIII and LuIII) and 3a'-(Dy, Co), which are characterized by nuclear magnetic resonance (NMR) analysis, electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS), and single-crystal X-ray analysis. Photophysical investigations disclose that the organic skeleton of 3a-(Ln, Zn) exhibits an excellent sensitizing ability toward SmIII, EuIII, and YbIII ions, displaying characteristic luminescence emission in both the visible and near-infrared (NIR) regions. AC susceptibility measurements of 3a'-(Dy, Co) reveal the frequency-independent performance under zero dc field, suggesting the absence of slow relaxation of magnetization. This work offers a new approach for the fabrication of discrete metallic covalent architectures with 3d-4f vertices.

Urinary metabonomic study using a CUMS rat model of depression.

Chronic unpredictable mild stress (CUMS) is a well-validated model of depression. In this study, a urinary metabonomics method based on the NMR spectrometry was used to study the metabolic perturbation in CUMS-induced rat depression model. With pattern recognition analysis, a clear separation of CUMS rats and healthy controls was achieved, and nine endogenous metabolites contributing to the separation were identified. CUMS-treated rats were characterized by the increase of glycine, pyruvate, glutamine, and asparagines, as well as the decrease of 2-oxoglutarate, dimethylglycine, citrate, succinate, and acetate. The urinary biochemical changes related to the metabolic disturbance in CUMS induced depression, and the possible correlations with live qi stagnation in traditional Chinese medicine are discussed. The work shows that CUMS is a reliable model for studying depression, and the noninvasive urinary metabolomic method is a valuable tool to investigate the biochemical pertubations in depression as an early diagnostic means.

Metabolic fingerprinting of Tussilago farfara L. using ¹H-NMR spectroscopy and multivariate data analysis.

INTRODUCTION: The flower bud of Tussilago farfara L. is widely used for the treatment of coughs, bronchitis and asthmatic disorders in traditional Chinese medicine. In Europe, the plant has been used as herbal remedies for virtually the same applications, but the leaves are preferred over flowers. OBJECTIVE: To systematically evaluate the chemical profiles of Tusssilago farfara leaves and flowers along with the identification of the polar and non-polar metabolites. METHODOLOGY: Metabolic profiling carried out by means of ¹H-NMR spectroscopy and multivariate data analysis was applied to crude extracts from flowers and leaves. Metabolites were identified directly from the crude extracts through one-dimensional and two-dimensional NMR spectra. RESULTS: A broad range of metabolites were detected without any chromatographic separation. Principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) of ¹H-NMR data provided a clear separation between the samples. The corresponding loadings plot indicated that higher levels of phenylpropanoids, amino acids, organic acids and fatty acids, as well as lower levels of sugars, terpenoids and sterols were present in the leaves, as compared with flowers. For the flowers, more phenylpropanoids were present in fully open flowers, while more sugars and fatty acids were present in flower buds. CONCLUSION: NMR spectra (one- and two-dimensional) are useful for identifying metabolites, especially for the overlapped signals. The NMR-based metabolomics approach has great potential for chemical comparison study of the metabolome of herbal drugs.

Cation modulated spin state and near room temperature transition within a family of compounds containing the same [FeL2]2- center.

Spin-crossover (SCO) active compounds have received much attention due to their potential application in molecular devices. Herein, a family of solvent-free FeII compounds, formulated as (A)2[FeL2], (H2L = pyridine-2,6-bi-tetrazolate, A = (Me)4N+1, Et2NH2+2, iPr2NH2+3 and iPrNH3+4), were synthesized and characterized. Single-crystal X-ray diffraction studies reveal that 1-4 are all supramolecular frameworks containing the same [FeL2]2- center, which is arranged into two packing modes via inter-molecular interactions, that is, a 3D architecture in 1 and 1D chain in 2-4. The spin states of 1-4 at different temperatures are assigned on the basis of the single-crystal X-ray diffraction data. Solid state magnetic investigations indicate that 1 and 4 exhibit a low spin state (below 350 K) and high spin state (2-400 K), respectively. 2 and 3 display clear SCO behavior in the measured temperature, but with different profiles and critical temperatures. 2 undergoes a complete gradual SCO with a critical temperature of T1/2 = 260 K. 3 has an abrupt near room temperature transition between T1/2 cooling = 278 K and T1/2 warming = 286, centered at 282 K (9 °C). This study reveals the importance of organic cations in the modulation of SCO behavior and offers a new insight for the design of SCO compounds with near room temperature spin transitions.

Effect of pegylated interferon-α2b add-on therapy on renal function in chronic hepatitis B patients: A real-world experience.

Background and aim: Controversy remains as to pegylated interferon-α (PEG-IFNα) antiviral therapy to renal function in chronic hepatitis B (CHB) patients. The aim of this study was to evaluate the influence of PEG-IFNα2b (Y shape, 40 kD) add-on treatment for renal function in CHB patients who received entecavir therapy. Methods: This was a retrospective observational study to investigate factors related to renal function in 114 CHB patients who received PEG-IFNα2b add-on therapy to entecavir for 48 weeks. Changes of blood urea nitrogen (BUN), serum creatinine (sCr), and estimated glomerular filtration rate (eGFR), which was calculated with both Chronic Kidney Disease Epidemiology Collaboration and Modification of Diet in Renal Disease (MDRD) formulas, were analyzed by one-way analysis of variance. A linear mixed effects model for repeated measures was used to assess the correlation between baseline information and eGFR changes at 24 and 48 weeks of therapy. The model considered the baseline age, gender, body weight, viral load, hepatitis B surface antigen, BUN, sCr, and treatment strategy as fixed effects and incorporated random effects for individual subjects. Results: BUN and sCr was decreased, while eGFR was increased at 12 weeks of therapy. Only eGFR maintained at 24 and 48 weeks of therapy. Patients with female gender, age ≥ 40 years, and baseline HBsAg level < 250 IU/mL showed significant improvement of renal function with PEG-IFNα2b add-on therapy. The linear mixed effects model revealed that female gender, baseline sCr, and PEG-IFNα2b add-on were significant positive predictors for eGFR elevation at 24 and 48 weeks of therapy. Conclusion: In real-world experience, PEG-IFNα2b add-on therapy might be associated with increased eGFR in CHB patients.