Porous carbon nanosheets derived from two-dimensional Fe-MOF for simultaneous voltammetric sensing of dopamine and uric acid.

It is of great significance for electrochemical sensors to simultaneously detect dopamine (DA) and uric acid (UA) related to biological metabolism. In this work, two-dimensional (2D) porous carbon nanosheets (CNS) was prepared as electrocatalysts to improve the sensitivity, the selectivity, and the detection limit of the simultaneous detection. First, 2D amorphous iron-metal organic frameworks (Fe-MOF) was synthesized with Fe3+and terephthalic acid via a facile wet chemistry method at room temperature. And then, CNS was prepared by pyrolysis and pickling of Fe-MOF. CNS had large specific surface area, good electrical conductivity and lots of carbon defects. The response currents of the CNS modified electrode was larger than those of the control electrodes in the simultaneous determination. The simultaneous determination was measured via differential pulse voltammetry to reduce the effect of capacitive currents on quantitative analysis. The CNS modified electrodes showed high sensitivity and low detection limit for the simultaneous detection of DA and UA. The modified electrodes have been successfully used to detect DA and UA in normal human serum.

Fabrication of fluorescent SiO2@zeolitic imidazolate framework-8 nanosensor for Cu(2+) detection.

A simple strategy to fabricate a fluorescent SiO2@zeolitic imidazolate framework-8 (ZIF-8) core-shell nanosensor for Cu(2+) detection was demonstrated in this work. The nanosensor was synthesized using carboxyl-functionalized SiO2 nanoparticles (SiO2 NPs) as a template to induce the growth of ZIF-8 on its surface. The porous SiO2@ZIF-8 exhibited extremely good adsorption properties and a large specific surface area to accumulate Cu(2+), and the pyridyl nitrogen sites in imidazole played vital roles in the recognition of Cu(2+). The fluorescent intensity decreased linearly with the increasing of Cu(2+) concentration in the range of 10-500 nM and the detection limit was estimated to be 3.8 nM. The SiO2@ZIF-8 nanosensor could be further used to determine trace amounts of Cu(2+) in real water samples, while some previous sensors had to be dispersed in organic solution for use, such as DMSO and MeCN. The core-shell nanostructures of SiO2@ZIF-8 made it possible for it to be dispersed directly in aqueous solution and prevented ZIF-8 from aggregation, which enhanced the sensing performance of the SiO2@ZIF-8 nanosensor.

Electrochemical sensing and biosensing platform based on biomass-derived macroporous carbon materials.

A three-dimensional (3D) macroporous carbon (3D-KSCs) derived from kenaf stem (KS) is proposed as a novel supporting material for electrochemical sensing and a biosensing platform. A series of 3D-KSCs/inorganic nanocomposites such as Prussian blue (PB) nanoparticles (NPs)-carboxylic group-functionalized 3D-KSCs (PBNPs-3D-FKSCs), CuNiNPs-3D-KSCs, and CoNPs-3D-KSCs were prepared by a facile two-step route consisting of carbonization and subsequent chemical synthesis or one-step carbonization of KS-metal ion complex. The obtained 3D-KSCs/inorganic nanocomposites were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy, scanning electron microscopy, and Fourier transform-infrared spectroscopy. A whole piece of 3D-KSCs/nanocomposites was used to prepare an integrated 3D-KSCs/nanocomposite electrode. Compared to the electrode modified by graphene, carbon nanotubes and their derivatives, which can form close-packed structure after assembled on electrode surface, the integrated 3D-KSCs/nanocomposite electrode shows a 3D honeycomb porous structure. Such structure provides a large specific surface area, effectively supports a large number of electro-active species, and greatly enhances the mass and electron transfer. The electrochemical behaviors and electrocatalytic performances of the integrated 3D-KSCs/inorganic nanocomposite electrode were evaluated by cyclic voltammetry and the amperometric method. The resulted PBNPs-3D-FKSCs, CuNiNPs-3D-KSCs, and CoNPs-3D-KSCs electrode show good electrocatalytic performances toward the reduction of H2O2, the oxidation of glucose and amino acid, respectively. Therefore, the low-cost, renewable, and environmentally friendly 3D-KSCs should be promising supporting materials for an electrochemical sensor and biosensor.

Functionalized lanthanide coordination polymer nanoparticles for selective sensing of hydrogen peroxide in biological fluids.

Lanthanide coordination polymers have recently emerged as very fascinating sensing materials due to their tunable structures and unique optical properties. However, a major problem concerning the applications of lanthanide coordination polymers for fluorescent sensing is their unselective recognition to analytes. In this work, a direct post-modification strategy was employed to prepare functionalized lanthanide coordination polymer nanoparticles (Phe/Tb-CPBA CPNPs) with specific response ability to hydrogen peroxide (H2O2) by using phenylalanine (Phe) as bridging ligands, terbium ions (Tb(3+)) as metal nodes and carboxyphenylboronic acids (CPBAs) as guest ligands. Phe/Tb-CPBA CPNPs emit a strong green fluorescence due to the removal of coordinated water molecules and the sensitization effect of CPBA. Upon the addition of H2O2, however, the quenched fluorescence of Phe/Tb-CPBA CPNPs can be observed owing to an intramolecular charge transfer effect. This finding led to a method for the quantitation of H2O2 in the 6 µM to 1 mM concentration range and with a detection limit at 2 µM. Because of the chemoselective H2O2-mediated oxidative deboronation, Phe/Tb-CPBA CPNPs as fluorescent sensors exhibit excellent selectivity to H2O2. Furthermore, Phe/Tb-CPBA CPNPs were successfully used to measure the level of H2O2 in urine samples and showed satisfactory results. We envision that the presented strategy could be extended to design other functionalized coordination polymers with desired functions for various biomedical applications.

Binding characteristics and interactive region of 2-phenylpyrazolo[1,5-c]quinazoline with DNA.

The interaction between 2-phenylpyrazolo[1,5-c]quinazoline (PQ) and DNA under physiological conditions was investigated using multi-spectroscopic techniques, atomic force microscopy and gel electrophoresis. The thermodynamic parameters were estimated and were discussed in detail. The results of fluorescence-quenching experiments indicated that the main interactive force between PQ and DNA was a hydrophobic interaction and that it was a static quenching process. Potassium iodide and single-strand (ss)DNA quenching studies, together with circular dichroism spectra implied groove binding of PQ with DNA. Atomic force microscopy and gel electrophoresis experiments suggested that there were no major conformational changes in DNA upon interaction with PQ. In addition, UV/vis absorption titration of DNA bases confirmed that PQ bound with DNA mainly through a minor groove interaction and preferentially interacted with adenine and thymine. We anticipate that this work will provide useful information for the application of quinazoline derivatives in the fields of medicinal and pharmaceutical chemistry.

A target-triggered ultra-sensitive aptasensor for simultaneous detection of Cd2+ and Hg2+ using MWCNTs-Au NPs modified electrode.

A sensitive electrochemical assay for simultaneously detecting cadmium ion (Cd2+) and mercury ion (Hg2+) with the aptamer as recognition unit was established, in which methylene blue (MB) and target-triggered in-situ generated Ag nanoclusters (Ag NCs) were identified as signal reporters. Multi-walled carbon nanotubes and gold nanoparticles composites were prepared with polyethyleneimine to amplify electrical signals of screen-printed electrodes. Due to the particular base sequences, MB labeled Cd2+ aptamer paired with ssDNA through T-Hg-T structure with Hg2+. Notably, the C-rich structure in ssDNA acted as a template for the generation of Ag NCs, which could induce differential pulse voltammetry signals corresponding to Hg2+ concentrations. This electrochemical aptasensor exhibited detection limits of 94.01 pg/mL and 15.74 pg/mL for Cd2+ and Hg2+, respectively. The developed aptasensor allowed for practical application to tea and vegetable samples with satisfactory accuracy. This work possesses potential in developing biosensing technologies for simultaneous determination of multiple heavy metals.

Time-Resolved FRET-Based Immunosensor for the Ultrasensitive and Rapid Detection of Cd2.

The detection of heavy metals in food is beneficial to public health. Herein, a new time-resolved fluorescent immunosensor based on the Förster resonance energy transfer (FRET) was proposed to rapidly detect a cadmium ion (Cd2+). After coupling with an antigen and a monoclonal antibody (mAb), respectively, the synthesized europium (III)-chelate-doped polystyrene time-resolved fluorescence microsphere-antigen (Eu-antigen) and gold nanoflowers-mAb (GNFs-mAb) interacted by antigen-antibody combination to quench fluorescence through FRET. Under optimal conditions, the Eu-GNF immunosensing platform provided a quick response to Cd2+ within 30 min. The limit of detection was 0.29 ng/mL with a linear range of 1-500 ng/mL. This immunosensor was further validated via graphite furnace atomic absorption spectrometry and exhibited satisfactory recovery for the detection of Cd2+ in four kinds of tea samples (98.82-108.01%). Thus, this strategy provides a good paradigm for the rapid and high-throughput detection of heavy metals in field testing.

Anti-Inflammatory Effects of Polyphenols from Plum (Prunus salicina Lindl) on RAW264.7 Macrophages Induced by Monosodium Urate and Potential Mechanisms.

Acute gouty arthritis is an acute inflammatory reaction caused by the deposition of monosodium urate (MSU) crystals in joints and surrounding soft tissues. Controlling inflammation is the key to preventing acute gouty arthritis. Anti-inflammatory activities and the possible molecular mechanisms of plum (Prunus salicina Lindl cv. "furong") polyphenols (PSLP) on RAW264.7 macrophage cells induced by monosodium urate were investigated. PPSF significantly inhibited the activity of inflammatory factors such as tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß), and interleukin-18 (IL-18). In addition, PPSF exhibited excellent activation of superoxide dismutase (SOD) activity and reduction of intracellular reactive oxygen species (ROS) and malondialdehyde (MDA) levels in RAW264.7 macrophages. The results of global screening of all transcripts by RNA-seq revealed 8585 differentially expressed genes between the PSLP-treated group and the MUS group. From GO analysis, PSLP could affect the occurrence and development of RAW264.7 macrophage inflammation through biological processes, such as organic substance metabolism, intracellular organelles, and binding function. The regulation mechanism of PSLP on MSU-induced RAW264.7 macrophage inflammation may be achieved through the HIF-1 signaling pathway, renal cell carcinoma, the ErbB signaling pathway, and the FoxO signaling pathway. Therefore, PSLP has great prospects in the prevention of gout and similar inflammatory diseases.

Effects of Different Blanching Methods on the Quality of Tremella fuciformis and Its Moisture Migration Characteristics.

Blanching is a critical step in the processing of Tremella fuciformis (T. fuciformis). The effects of different blanching methods (boiling water blanching (BWB), ultrasonic-low temperature blanching (ULTB), and high-temperature steam (HTS)) on the quality and moisture migration characteristics of T. fuciformis were investigated. The results showed that the T. fuciformis blanched by ULTB (70 °C, 2 min, 40 kHz, 300 W) had the best quality, including a brighter appearance, superior texture, and good sensory features, with a polysaccharide content of 3.90 ± 0.02%. The moisture migration characteristics of T. fuciformis after blanching exhibited four peaks, displayed strong and weak chemically bound water, immobilized water, and free water, whereas ULTB had a weak effect on the freedom of water in T. fuciformis. The study will provide the foundation for the factory processing of T. fuciformis.

Structural Characterization and Anti-Inflammatory Activity of Polysaccharides from Tremella fuciformis on Monosodium Urate-Stimulated RAW264.7 Macrophages.

The structural characteristics and anti-inflammatory activity of Tremella fuciformis polysaccharides (TFPs) were investigated. The study showed that TFPs were mainly composed of mannose, rhamnose, glucuronic acid, glucose, galactose, xylose, and fucose. TFPs significantly inhibited monosodium urate (MSU)-induced inflammation of RAW264.7 cells, as well as the secretion levels of TNF-α, IL-1ß, and IL-18 cytokines. The concentrations of malondialdehyde and reactive oxygen species in RAW264.7 macrophages were reduced, but superoxide dismutase activity was increased. RNA-Seq technology was applied to explore the mechanisms of TFPs ameliorating MSU-induced inflammation of RAW264.7 macrophages. Results revealed that TFPs significantly reduce MSU-stimulated inflammatory damage in RAW 264.7 cells by inhibiting signaling pathways like the hypoxia inducible factor-1 (HIF-1) signaling pathway and erythroblastic oncogene B (ErbB) signaling pathway. This study provides a foundation for TFPs to be developed as novel anti-inflammatory drugs.

High-Performance Au@Ag Nanorods Substrate for SERS Detection of Malachite Green in Aquatic Products.

In order to improve the detection performance of surface-enhanced Raman scattering (SERS), a low-cost Au@Ag nanorods (Au@Ag NRs) substrate with a good SERS enhancement effect was developed and applied to the detection of malachite green (MG) in aquaculture water and crayfish. By comparing the SERS signal enhancement effect of five kinds of Au@Ag NRs substrates with different silver layer thickness on 4-mercaptobenzoic acid (4-MBA) solution, it was found that the substrate prepared with 100 µL AgNO3 had the smallest aspect ratio (3.27) and the thickest Ag layer (4.1 nm). However, it showed a good signal enhancement effect, and achieved a detection of 4-MBA as low as 1 × 10-11 M, which was 8.7 times higher than that of the AuNRs substrate. In addition, the Au@Ag NRs substrate developed in this study was used for SRES detection of MG in crayfish; its detection limit was 1.58 × 10-9 M. The developed Au@Ag NRs sensor had the advantages of stable SERS signal, uniform size and low cost, which provided a new tool for SERS signal enhancement and highly sensitive SERS detection method development.

Metastatic splenic α-fetoprotein-producing adenocarcinoma: report of a case.

Solitary carcinomatous metastases to the spleen are rare, and the presence of solitary splenic metastasis of hepatoid adenocarcinomas (HAC) has not yet been reported. We herein present the case of a 54-year-old male patient who developed a metastatic tumor to the spleen with enhanced levels of serum α-fetoprotein and carcinoembryonic antigen (CEA). The patient underwent a gastrectomy due to adenocarcinoma of the stomach 5 years previously. The tumor was diagnosed on the grounds of histopathology and immunohistochemical staining after splenectomy. The pathology slides showed both adenocarcinoma and hepatoid structures. α-Fetoprotein antibody staining was positive in the tumor, suggesting hepatoid characteristics. After the operation, the patient recovered well and had no signs of recurrence at a follow-up examination after 9 months. Together with this case, several aspects of the disease are discussed after a review of the current literature.

Simultaneous electrochemical sensing of heavy metal ions based on a g-C3N4/CNT/NH2-MIL-88(Fe) nanocomposite.

The presence of Cd2+, Pb2+, Cu2+ and Hg2+ in drinking-water can be harmful to human health, even if their concentration is fairly low. Hence, it is significant to detect these heavy metal ions in sewage to evaluate the quality of water. Herein, amino-functionalized metal-organic frameworks (NH2-MIL-88(Fe)) embedded with graphitic carbon nitride (g-C3N4) nanosheets and acid-functionalized carbon nanotubes were prepared via a one-pot synthesis. The composite can be directly modified on the surface of glass carbon electrodes without the assistance of Nafion or other binders. The modified glass carbon electrodes can be used to simultaneously detect Cd2+, Pb2+, Cu2+ and Hg2+ in water via square wave stripping voltammetry. The doping of g-C3N4 in the composite, rich in N-containing functional groups, participates in the adsorption of metal ions on the surface of the electrodes. The porous composite provides accommodation room for metals generated by electro-reduction. The detection limit for Cd2+, Pb2+, Cu2+ and Hg2+ is 39.6 nM, 7.6 nM, 11.9 nM, and 9.6 nM, respectively. And the sensitivity for Cd2+, Pb2+, Cu2+ and Hg2+ is 0.0789 mA µM-1 cm-2, 0.4122 mA µM-1 cm-2, 0.2616 mA µM-1 cm-2, and 0.3251 mA µM-1 cm-2, respectively. This work not only enriches the functional design of Fe-MOF materials, but also develops a method for the determination of metal ions using the adsorption sites in g-C3N4.

A novel SERPINE1-FOSB fusion gene in pseudomyogenic hemangioendothelioma results in activation of intact FOSB and the PI3K-AKT-mTOR signaling pathway and responsiveness to sirolimus.

Pseudomyogenic hemangioendothelioma (PHE) is an extremely rare disease that affects mainly the young and more men than women. PHE are multicentric, locally aggressive, have low metastatic potential, and affect multiple tissue planes. Genetic aberrations are frequently detected in PHE and may play important roles in the occurrence, development, and treatment of this disease. In this study, we report a case of PHE with a novel SERPINE1-FOSB fusion gene. The fusion introduced a strong promoter near the coding region of FOSB, resulting in overexpression of intact FOSB. Immunohistochemical analysis showed overexpression of pAKT and mTOR in tumor cells, suggesting activation of the PI3K-AKT-mTOR signaling pathway. The patient responded well to targeted therapy with sirolimus, an mTOR inhibitor. Our study correlated dysregulation of a specific signaling pathway and the effectiveness of a targeted therapy to a specific genetic aberration. This information may be useful for future investigations of targeted therapeutics and provide a potential predictive biomarker for therapeutic effectiveness in PHE cases.

Decorating multi-walled carbon nanotubes with quantum dots for construction of multi-color fluorescent nanoprobes.

Novel multi-color fluorescent nanoprobes were prepared by electrostatically assembling differently sized CdTe quantum dots on polyethylenimine (PEI) functionalized multi-walled carbon nanotubes (MWNTs). The structural and optical properties of the nano-assemblies (MWNTs-PEI-CdTe) were characterized by transmission electron microscopy (TEM), electron diffraction spectra (EDS), Raman spectroscopy, confocal microscopy and photoluminescence spectroscopy (PL), respectively. Electrochemical impedance spectroscopy (EIS) was also applied to investigate the electrostatic assembling among oxidized MWNTs, PEI and CdTe. Furthermore, confocal fluorescence microscopy was used to monitor the nano-assemblies' delivery into tumor cells. It was found that the nano-assemblies exhibit efficient intracellular transporting and strong intracellular tracking. These properties would make this luminescent nano-assembly an excellent building block for the construction of intracellular nanoprobes, which could hold great promise for biomedical applications.

The electrodeposition of Ag nanoparticles on a type I collagen-modified glassy carbon electrode and their applications as a hydrogen peroxide sensor.

Silver nanoparticles (Ag NPs) attached to type I collagen-modified glassy carbon (GC) electrodes were successfully synthesized by the electrodepositing method. Atomic force microscopy images showed that many Ag NPs with homogeneous size were formed and uniformly distributed on the type I collagen/GC electrode. The amount, size and distribution of Ag NPs could be controlled by the collagen. The results of electrochemical experiments showed that Ag NPs had an excellent catalytic ability for the reduction of hydrogen peroxide (H(2)O(2)), suggesting that they could be used as a sensor to determine H(2)O(2). The good catalytic activity of the Ag NPs was ascribed to the type I collagen that resulted in the homogeneous distribution of Ag NPs with small size. The effects of type I collagen concentration and electrodeposition time on Ag NPs were investigated. When the Ag NPs were used as a sensor to determine H(2)O(2), the sensor could achieve 95% of the steady-state current in less than 2 s and had a linear range of 5.0 microM to 40.6 mM and a 0.7 microM detection limit of H(2)O(2) at a signal-to-noise ratio of 3.

[Preparation of the Silane Monolayer on Magnetite Nanoparticles and Its Performance with Respect to Phosphate Removal from Water].

We studied the loading of N-(2-Aminoethyl)-3-aminopropyl trimethoxy silane from aqueous solution as a monolayer on magnetite nanoparticles and examined the phosphate removal performance of the generated adsorbent (silane monolayer on magnetite nanoparticles, abbreviated as MSMNPs). The results indicate that silane monolayer adsorption on magnetite nanoparticles occurred at low concentrations (equilibrium silane concentration <300 mg·L-1) and a~100% surface monolayer coverage by silane could be established at a temperature ≥ 90℃ or a NaCl concentration ≥ 0.1 mol·L-1. The FTIR and XPS spectra indicate that hydrolyzed silane and magnetite nanoparticles are chemically linked. The loading of silane as a monolayer did not significantly change the saturation magnetization. The adsorption isotherm of phosphate based on MSMNPs fit the Langmuir model better, with a calculated maximum adsorption capacity reaching 7.59 mg·g-1. The adsorption and desorption of phosphate by MSMNPs are very fast, exceeding 90% within 30 min and reaching an equilibrium within 1 h. In conclusion, MSMNPs are novel adsorbents with easy separability, which enables the repeated use, and rapid adsorption and desorption of pollutants.

Inactivation of phosphorus in the sediment of the Lake Taihu by lanthanum modified zeolite using laboratory studies.

Release of phosphorus (P) from sediment to overlying water has to be dealt with to address algal blooms in eutrophic lakes. In this study, the sediment from the Lake Taihu was amended with lanthanum modified zeolite (LMZ) to reduce P release under different pH, temperature and anaerobic conditions. LMZ performed well, to decreasing P concentration in Lake Taihu water in the presence of sediment. The EPC0 value, the critical P concentration at which there was neither P adsorption nor P release, was lowered by adding LMZ, suggesting that amendment with LMZ could diminish the risk of P release from the sediment. From the Langmuir isotherm model, the adsorption capacity of phosphate by LMZ was estimated to be 64.1 mgP/g. The LMZ-amended sediment had a higher content of stable P forms (HCl-P and Res-P) and a lower content of P forms with a high (NH4Cl-P and BD-P) or medium-high (NaOH-P and Org-P) risk of release, when compared with the original sediment. The fractionation simulates conditions which release potentially mobile P which can then be simply re-bound to LMZ. At high pH (>9.0), anaerobic condition or high temperature promoted the liberation of P from sediment. However, P release could be greatly inhibited by LMZ. In addition, although Mn2+ and NH4+ ions were released from sediment under the anaerobic condition, the release could also be hindered by adding LMZ. LMZ is a promising P inactivation agent to manage eutrophication in the sediment of Lake Taihu.

Microfluidic Device Directly Fabricated on Screen-Printed Electrodes for Ultrasensitive Electrochemical Sensing of PSA.

How to fabricate scale low-cost microfluidic device for detection of biomarkers owns a great requirement. Herein, it is for the first time reported that a new microfluidic device based on bonding polydimethylsiloxane microfluidic channels onto the substrate of a screen-printed electrode with coating glass solution was fabricated for electrochemical sensing of prostate-specific antigen (PSA). Compared to traditional microfabrication processes, this method is simple, fast, low cost, and also suitable for mass production. The prepared screen-printed electrode-based microfluidic device (CASPE-MFD) was used for the detection of the PSA in human serum. The prepared CASPE-MFD had a detection limit of 0.84 pg/mL (25.8 fM) and a good linearity with PSA concentration ranging from 0.001 to 10 ng/mL, which showed a great promise platform toward the development of miniaturized, low-cost electrochemical microfluidic device for use in human health, environmental monitoring, and other applications.

Fisetin inhibits the proliferation of gastric cancer cells and induces apoptosis through suppression of ERK 1/2 activation.

The present study aimed to investigate the effect of fisetin on proliferation and apoptosis of gastric cancer cells, as well as the underlying mechanism. Proliferation in SGC7901 cancer and GES-1 normal cells was analyzed using a CCK-8 assay. Apoptosis was analyzed using an Annexin V/Propidium Iodide apoptosis kit and phosphorylation of extracellular signal-regulated kinase (ERK) 1/2 was analyzed by western blot assay. Treatment of SGC7901 cells with various concentrations (1, 5, 10, 15 and 20 µM) of fisetin for 48 h resulted in a concentration dependent reduction in proliferation. Flow cytometry revealed a marked increase in apoptosis from 5 µM concentration of fisetin after 48 h. The percentage of apoptotic cells increased to 87% following treatment with 15 µM fisetin for 48 h, compared with 2% in control. Treatment of SGC7901 cells with fisetin for 48 h resulted in a reduction in the activation of ERK 1/2 in a concentration-dependent manner. The reduction in activation of ERK 1/2 was significant following treatment with 15 µM fisetin for 48 h. The inhibitory effect of fisetin on activation of ERK 1/2 was further demonstrated using the ERK 1/2 inhibitor, PD98059. The results indicated a significant reduction in the proliferation of SGC7901 cells following treatment with PD98059 (P<0.002). The reduction by PD98059 administration was comparable to that observed following fisetin treatment for 48 h. In conclusion, the current study demonstrates that fisetin inhibits the proliferation of gastric cancer cells and induces apoptosis through suppression of ERK 1/2 activation. Thus, fisetin may have therapeutic applications in the treatment of gastric cancer.