Phenanthroline-based microporous organic materials for removal of Cu(II) from aqueous solution and reutilization of spent adsorbent as catalysts.

Microporous organic polymers (MOPs) possessing large specific surface area with high stability are suitable adsorbent to remove contaminants from water, such as organic pollutant and heavy metal contaminants. Herein, a phenanthroline-based microporous organic polymer (Phen-MOP) has been synthesized through the coupling between benzene and 1,10-phenanthroline. The adsorption kinetics and thermodynamics were investigated. This Phen-MOP exhibited good adsorption efficiency for removal of Cu(II) from water with high structural stability and reusability. The maximum removal efficiency could reach to 98.47% at a Cu(II) concentration of 20 mg/L, pH = 7, 25 °C. It was found by investigating the adsorption isotherms that the maximum adsorption capacity Qm was 128.53 mg/g. Interestingly, after the adsorption of Cu(II), the resulting Phen-MOP-Cu can serve as an efficient heterogeneous catalyst for the Ullmann-type reaction. The structure and composition of the Phen-MOP-Cu were characterized by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), Brunauer-Emmett-Teller (BET), scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS). The results indicated that this catalyst possessed immense specific surface area, large pore volume and high stability. The catalyst was easily recyclable and did not significantly lose catalytic activity after being reused six times.

Green tea protects against hippocampal neuronal apoptosis in diabetic encephalopathy by inhibiting JNK/MLCK signaling.

Although diabetic encephalopathy (DE) is a major late complication of diabetes, the pathophysiology of postural instability in DE remains poorly understood. Prior studies have suggested that neuronal apoptosis is closely associated with cognitive function, but the mechanism remains to be elucidated. Green tea, which is a non­fermented tea, contains a number of tea polyphenols, alkaloids, amino acids, polysaccharides and other components. Some studies have found that drinking green tea can reduce the incidence of neurodegenerative diseases and improve cognitive dysfunction. We previously found that myosin light chain kinase (MLCK) regulates apoptosis in high glucose­induced hippocampal neurons. In neurodegenerative diseases, including Alzheimer's disease and Parkinson's disease, activation of the JNK signaling pathway promotes neuronal apoptosis. However, the relationship between JNK and MLCK remains to be elucidated. Green tea serum was obtained using seropharmacological methods and applied to hippocampal neurons. In addition, a type 1 diabetes rat model was established and green tea extract was administered, and the Morris water maze test, Cell Counting Kit­8 assays, flow cytometry, western blotting and terminal deoxynucleotidyl transferase­mediated dUTP nick end­labelling assays were used to examine the effects of green tea on hippocampal neuronal apoptosis in diabetic rats. The results demonstrated that green tea can protect against hippocampal neuronal apoptosis by inhibiting the JNK/MLCK pathway and ultimately improves cognitive function in diabetic rats. The present study provided novel insights into the neuroprotective effects of green tea.

Facile one-pot synthesized hydrothermal carbon from cyclodextrin: A stationary phase for hydrophilic interaction liquid chromatography.

A new hydrothermal carbon was prepared by a "one-pot" hydrothermal transformation of ß-cyclodextrin on silica microspheres (noted as silica@HTC microspheres), which was featuring as a new stationary phase for the hydrophilic interaction liquid chromatography (HILIC). The synthesized silica@HTC possessed polar groups of hydroxyl, carbonyl and carboxyl groups arising from the carbonization transformation of ß-cyclodextrin. As demonstrating great hydrophilicity, the silica@HTC was applied as an excellent HILIC stationary phase for the separation of polar compounds including phenols and the endocrine disrupting chemicals (EDCs). In comparison with commercial available HILIC stationary phases, the separation performance of the silica@HTC stationary phase was superior in the separation of phenols and EDCs. The mild hydrothermal carbon transformation of the ß-cyclodextrin on the silica microspheres in the "one-pot" manner would represent a new and simple approach to prepare a new class of saccharide-derived stationary phases by using saccharides as precursors.

LncRNA CRNDE promotes the epithelial-mesenchymal transition of hepatocellular carcinoma cells via enhancing the Wnt/ß-catenin signaling pathway.

Colorectal neoplasia differentially expressed (CRNDE) is a significantly upregulated long noncoding RNA in hepatocellular carcinoma (HCC). CRNDE could promote cell proliferation, migration, and invasion, while its molecular mechanisms were still largely unclear. In this study, we investigated the expression and function of CRNDE. CRNDE was significantly upregulated in tumor tissues compared with adjacent normal tissues. In vitro, we revealed that knockdown of CRNDE inhibited cell proliferation, migration, and cell invasion capacities in HCC. Animal studies indicated that CRNDE knockdown represses both growth and metastasis of HCC tumors in vivo. Moreover, knockdown of CRNDE suppressed the cell epithelial-mesenchymal transition (EMT) process by increasing the expression of E-cadherin and ZO-1, whereas, decreasing the expression of N-cadherin, slug, twist, and vimentin in HCC cells. We also revealed that knockdown of CRNDE suppressed the Wnt/ß-catenin signaling in HCC. Thus, CRNDE could modulate EMT of HCC cells and knockdown of CRNDE impaired the mesenchymal properties. CRNDE increased invasion of HCC cells might be through activating the Wnt/ß-catenin signaling pathway.

A nano-bio interfacial protein corona on silica nanoparticle.

Nano-bio interaction takes the crucial role in bio-application of nanoparticles. The systematic mapping of interfacial proteins remains the big challenge as low level of proteins within interface regions and lack of appropriate technology. Here, a facile proteomic strategy was developed to characterize the interfacial protein corona (noted as IPC) that has strong interactions with silica nanoparticle, via the combination of the vigorous elution with high concentration sodium dodecyl sulfate (SDS) and the pre-isolation of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The trace level IPCs for silica nanoparticle were thus qualitatively and quantitatively identified. Bioinformatics analyses revealed the intrinsic compositions, relevance and potential regularity addressing the strong interactions between IPC and nanoparticle. This strategy in determining IPCs is opening an avenue to give a deep insight to understand the interaction between proteins and not only nanoparticles but also other bulk materials.

Highly Porous Metal-Free Graphitic Carbon Derived from Metal-Organic Framework for Profiling of N-Linked Glycans.

In this work, a highly efficient profiling of N-linked glycans was achieved by a facile and eco-friendly synthesized highly porous metal-free carbon material. The metal-free carbon was derived from a well-defined nanorod zinc metal-organic framework via the metal removal under a high-temperature carbonization, which exhibited a highly specific surface area of 1700 m2/g. After further oxidation, the oxidized metal-free carbon was applied to the selective isolation of N-linked glycans from complex biological samples due to the strong interaction between carbon and glycan as well as the size-exclusion mechanism. Twenty six N-linked glycans could be identified from the digest of a standard glycoprotein ovalbumin at a concentration of 0.01 µg/µL, and the detection limit of glycans could be down to 1 ng/µL with 21 N-linked glycans identified. When the mass ratio of the interfering protein bovine serum albumin vs a standard ovalbumin digest is up to 500:1, there were 24 N-glycans confidentially identified. From a real complex sample of a healthy human serum, there were 43 N-linked glycans identified after the enrichment of oxidized metal-free carbon. In a word, the metal-free carbon is opening up new prospect for the high-throughput identification of glycan.

Preparation of organic-silica hybrid monolithic columns via crosslinking of functionalized mesoporous carbon nanoparticles for capillary liquid chromatography.

An organic-silica hybrid monolithic capillary column was fabricated by crosslinking (3-aminopropyl)trimethoxysilane (APTMS) modified mesoporous carbon nanoparticles (AP-MCNs) with tetramethoxysilane (TMOS) and n-butyltrimethoxysilane (C4-TriMOS). Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy, mercury intrusion porosimetry and inverse size-exclusion chromatography characterization proved the successful immobilization of mesoporous carbon nanoparticles (MCNs). The crosslinking of AP-MCNs into the hybrid monolithic matrix has significantly increased the reversed-phase retention of alkylbenzenes and chromatographic performance for small molecules separations in comparison with the neat one without MCNs. The resulting column efficiency of the mesoporous carbon nanoparticle-based butyl-silica hybrid monolithic column (MCN-C4-monolith) was up to ca. 116,600N/m for the capillary liquid chromatography (cLC) separation of butylbenzene. Enhanced performance of proteins separation was achieved on the MCN-C4-monolith in comparison with the butyl-silica hybrid monolithic column without MCN (C4-monolith). The separation of peptides from bovine serum albumin (BSA) digest was carried out on the MCN-C4-monolith by capillary liquid chromatography-tandem mass spectrometry (cLC-MS/MS) with protein sequence coverage of 81.9%, suggesting its potential application in proteomics.

Dual-Metal Centered Zirconium-Organic Framework: A Metal-Affinity Probe for Highly Specific Interaction with Phosphopeptides.

The highly specific affinity between probes and phosphopeptides is the fundamental interaction for selective identification of phosphoproteomes that uncover the mechanisms of signal transduction, cell cycle, enzymatic regulation, and gene expression in biological systems. In this study, a metal-affinity probe possessing both interactions of metal oxide affinity chromatography (MOAC) and immobilized metal ion affinity chromatography (IMAC) was facilely prepared by immobilizing zirconium(IV) on a zirconium-organic framework of UiO-66-NH2, which holds dual-metal centers of not only the inherent Zr-O cluster but also the immobilized Zr(IV) center. This dual-metal centered zirconium-organic framework (DZMOF) demonstrates as a highly specific metal-affinity probe toward the extraction of phosphopeptides due to the metal-affinity interactions of MOAC and IMAC toward either mono-phosphorylated or multi-phosphorylated peptides. The binding energies of zirconium 3d5/2 and 3d3/2 in this DZMOF are 183.07 and 185.47 eV, respectively, which are higher than those of the intact UiO-66-NH2 (182.84 and 185.17 eV, respectively), confirming the higher metal-affinity interaction between the DZMOF and phosphopeptides. This high metal-affinity probe presents an unprecedented strong performance in anti-nonspecific interference during the capturing of phosphopeptides of ß-casein with the molar ratio of ß-casein vs bovine serum albumin up to ca. 1:5000. The enrichment of phosphopeptides from a human saliva sample by DZMOF further confirms the great potential of DZMOF in the extraction of low-abundance phosphopeptides for real complex biological samples.

One-Pot Approach to Prepare Organo-silica Hybrid Capillary Monolithic Column with Intact Mesoporous Silica Nanoparticle as Building Block.

A facile "one-pot" approach to prepare organo-silica hybrid capillary monolithic column with intact mesoporous silica nanoparticle (IMSN) as crosslinker and building block was described. An IMSN crosslinked octadecyl-silica hybrid capillary monolithic column (IMSN-C18 monolithic column) was successfully prepared, and the effects of fabrication conditions (e.g. concentration of intact mesoporous silica nanoparticle, polycondensation temperature, content of vinyltrimethoxysilane and stearyl methacrylate) on the structures of the IMSN-C18 monolithic column were studied in detail. The IMSN-C18 hybrid monolithic column possessed uniform morphology, good mechanical and pH stability (pH 1.1-11), which was applied to the separations of alkyl benzenes, polycyclic aromatic hydrocarbons (PAHs), as well as proteins. The minimum plate height of 10.5 µm (corresponding to 95000 N m-1) for butylbenzene and high reproducibility were achieved. The analysis of tryptic digest of bovine serum albumin (BSA) was carried out on the IMSN-C18 monolithic column by cLC coupled mass spectrometry (cLC-MS/MS), with the protein sequence coverage of 87.5% for BSA, demonstrating its potential application in proteomics.

Facile synthesis of gold@graphitized mesoporous silica nanocomposite and its surface-assisted laser desorption/ionization for time-of-flight mass spectroscopy.

In this work, a novel core-shell structured gold@graphitized mesoporous silica nanocomposite (Au@GMSN) was synthesized by in situ graphitization of template within the mesochannels of mesoporous silica shell on gold core and demonstrated to be promising nanomaterials for surface-assisted laser desorption/ionization time-of-flight mass spectroscopy (SALDI-TOF MS). The integration of the graphitized mesoporous silica with the gold nanoparticles endowed Au@GMSN with large surface areas of graphitic structure, good dispersibility, and strong ultraviolet (UV) absorption. Au@GMSN exerted the synergistic effect on the efficient detection of small-molecular-weight analytes including amino acids, neutral saccharides, peptides, and traditional Chinese medicine. The Au@GMSN-assisted laser desorption/ionization exhibited the following superiorities: high ionization efficiency, low fragmentation interference, favorable salt tolerance, and good reproducibility. Moreover, because of the large hydrophobic inner surface area of the graphitized mesoporous silica shell, the Au@GMSN demonstrated its promising capacity in the pre-enrichment of aromatic analytes prior to SALDI-TOF MS, which favored rapid and sensitive detection.

Interlayer water regulates the bio-nano interface of a ß-sheet protein stacking on graphene.

Using molecular dynamics simulations, we investigated an integrated bio-nano interface consisting of a ß-sheet protein stacked onto graphene. We found that the stacking assembly of the model protein on graphene could be controlled by water molecules. The interlayer water filled within interstices of the bio-nano interface could suppress the molecular vibration of surface groups on protein, and could impair the CH···π interaction driving the attraction of the protein and graphene. The intermolecular coupling of interlayer water would be relaxed by the relative motion of protein upon graphene due to the interaction between water and protein surface. This effect reduced the hindrance of the interlayer water against the assembly of protein on graphene, resulting an appropriate adsorption status of protein on graphene with a deep free energy trap. Thereby, the confinement and the relative sliding between protein and graphene, the coupling of protein and water, and the interaction between graphene and water all have involved in the modulation of behaviors of water molecules within the bio-nano interface, governing the hindrance of interlayer water against the protein assembly on hydrophobic graphene. These results provide a deep insight into the fundamental mechanism of protein adsorption onto graphene surface in water.

Spatial blockage of ionic current for electrophoretic translocation of DNA through a graphene nanopore.

Graphene nanopore has been promising the ultra-high resolution for DNA sequencing due to the atomic thickness and excellent electronic properties of the graphene monolayer. The dynamical translocation phenomena and/or behaviors underneath the blocked ionic current, however, have not been well unveiled to date for the translocation of DNA electrophoretically through a graphene nanopore. In this report, the assessment on the sensitivity of ionic current to instantaneous statuses of DNA in a 2.4 nm graphene nanopore was carried out based on the all-atom molecular dynamics simulations. By filtering out the thermal noise of ionic current, the instantaneous conformational variations of DNA in a graphene nanopore have been unveiled from the fluctuations of ionic current, because of the spatial blockage effect of DNA against ionic current. Interestingly, the neighborhood effect of DNA against ionic current was also observed within a distance of 1.5 nm nearby the graphene nanopore, suggesting the further precise control for DNA translocation through a graphene nanopore in gene sequencing. Moreover, the sensitivity of the blocked ionic current toward the instantaneous conformations of DNA in a graphene nanopore demonstrates the great potential of graphene nanopores in the dynamics analysis of single molecules.