Specific capture and determination of glycoprotein using a hybrid epitopes and monomers-mediated molecular-imprinted polymer enzyme-free electrochemical biosensor.

A novel molecular-imprinted polymer (MIP)-based enzyme-free biosensor was created for the selective detection of glycoprotein transferrin (Trf). For this purpose, MIP-based biosensor for Trf was prepared by electrochemical co-polymerization of novel hybrid monomers 3-aminophenylboronic acid (M-APBA) and pyrrole on a glassy carbon electrode (GCE) modified with carboxylated multi-walled carbon nanotubes (cMWCNTs). Hybrid epitopes of Trf (C-terminal fragment and glycan) have been selected as templates. The produced sensor exhibited great selective recognition ability toward Trf under optimal preparation conditions, offering good analytical range (0.125-1.25 µM) with a detection limit of 0.024 µM. The proposed hybrid epitope in combination with hybrid monomer-mediated imprinting strategy was successfully applied to detect Trf in spiked human serum samples, with recoveries and relative standard deviations ranging from 94.7 to 106.0% and 2.64 to 5.32%, respectively. This study provided a reliable protocol for preparing hybrid epitopes and monomers-mediated MIP for the synergistic and effective determination of glycoprotein in complicated biological samples.

An edible molecularly imprinted material prepared by a new environmentally friendly deep eutectic solvent for removing oxalic acid from vegetables and human blood.

A novel deep eutectic solvent-magnetic molecularly imprinted polymer (DES-MMIP) for the specific removal of oxalic acid (OA) was prepared by an environmentally friendly deep eutectic solvent, consisting of betaine, citric acid, and glycerol, which acted as the functional monomer for polymerization. The structure and morphology of DES-MMIPs were studied by X-ray diffraction, scanning and transmission electron microscopy, thermal gravimetric analysis, Fourier transform infrared spectroscopy, and vibrating sample magnetometer. DES-MMIPs had a core-shell structure, with magnetic iron oxide as the core, and showed good thermal stability and high adsorption capacity (18.73 mg/g) for OA. The adsorption process of OA by DES-MMIPs followed the pseudo-second-order kinetic model and Langmuir isotherm model. DES-MMIPs had significant selectivity for OA and their imprinting factor was 3.26. When applied to real samples, high performance liquid chromatography analysis showed that DES-MMIPs could remove OA from both spinach and blood serum. These findings provide potential methods for removal of OA from vegetables and for specific removal of OA in renal dialysis.

Rapid measurements of curcumin from complex samples coupled with magnetic biocompatibility molecularly imprinted polymer using electrochemical detection.

Curcumin widely exists in food, and rapid selective and accurate detection of curcumin have great significance in chemical industry. In this experiment, a new magnetic biocompatibility molecularly imprinted polymer was prepared with nontoxic and biocompatible Zein to adsorb curcumin selectively. The polymer has high biocompatibility, good adsorption capacity, and specific adsorption for curcumin. Combined with portable electrochemical workstations, the polymer can be used to detect curcumin rapidly and cost-effectively. Using curcumin as a template and Zein as the crosslinking agent, the polymers were synthesized on the surface of Fe3 O4 particles for solid phase extraction. The experimental results showed that the polymer reached large adsorption capacity (32.12 mg/g) with fast kinetics (20 min). The adsorption characteristic of the polymer followed the Langmuir isotherm and pseudo-second-order kinetic models. Hexacyanoferrate was used as electrochemical probe to generate signals, and the linear range was 5-200 µg/mL for measuring curcumin. The experimental analysis showed that the polymer was an ideal material for selective accumulation of curcumin from complex samples. This approach has been successfully applied to the determination of curcumin in food samples with electrochemical detection, indicating that this is a feasible and practical technique.

[Rotective Effects of Quercetin Against the Triptolide Induced Liver Injury and Relevant Mechanism Study].

OBJECTIVE: To explore the protective effects of quercetin (QE) on triptolide (TP) induced liver injury and the relevant mechanism. METHODS: Forty C57BL/6 mice were equally divided into 4 groups, control group, TP model group, 20 mg/kg QE treatment group and 80 mg/kg QE treatment group randomly. The 20 mg/kg and 80 mg/kg QE groups were gastrointestinal administration with QE at the dose of 0.2 mL/10 g for 10 d, twice daily, while other groups were administrated with equivalent normal saline. Four hours post the last dose, animals were gastrointestinal administered with TP at a dose of 500 µg/kg per mouse, except for NS control. All the mice were sacrificed 22 h later, blood and liver tissue samples were collected. The pathologic change of liver tissue was detected by HE staining. The level of aminotransferase (AST) and aspartate alanine aminotransferase (ALT) in serum, and the level of glutathione (GSH), malondialdehyde (MDA) and superoxide dismutase (SOD) in liver tissue homogenates were detected using the commercial kits. The level of interleukin (IL)-17, IL-10 and IL-6 in liver tissue homogenates was measured by ELISA. Hepatic expression of Toll-like receptor 4 (TLR4) was detected by Western blot. RESULTS: Compared with the control group, in the TP model group, hepatic lobule structure atrophied and even disappeared, hepatic cell necrosis and inflammatory cell infiltration are obvious. Additionally, in TP model group, serum ALT, AST and MDA levels were significantly increased, SOD and GSH levels were decreased, IL-6 and IL-17 levels were increased, IL-10 levels were decreased, and TLR4 protein levels were increased (P < 0.05). Compared with the TP model group, liver tissue injury and inflammatory cell infiltration were reduced in the QE group, and serum levels of ALT, AST, MDA, IL-6 and IL-17 were all decreased. TLR4 expression was down-regulated (P < 0.05) in both QE groups, and the decease levle was more significant in the high-dose QE group (P < 0.05, compared with the low-dose QE group). CONCLUSION: Quercetin can reduce TP-induced liver injury by reducing oxidative damage, promoting antioxidant and regulating cytokine secretion.

Preparation and evaluation of temperature and magnetic dual-responsive molecularly imprinted polymers for the specific enrichment of formononetin.

Thermo-responsive magnetic molecularly imprinted polymers were prepared by simple surface molecular imprinting polymerization for the selective adsorption and enrichment of formononetin from Trifolium pretense by temperature regulation. Using formononetin as a template, N-isopropylacrylamide as the thermo-responsive functional monomer, and methacrylic acid as an assisting functional monomer, the polymers were synthesized on the surface of the magnetic substrate. The results show that imprinted polymers attained controlled adsorption of formononetin in response to the temperature change, with large adsorption capacity (16.43 mg/g), fast kinetics (60 min) and good selectivity at 35°C compared with that at 25 and 45°C. The selectivity experiment indicated that the materials had excellent recognition ability for formononetin and the selectivity factors were between 1.32 and 2.98 towards genistein and daidzein. The excellent linearity was attained in the range of 5-100 µg/mL, with low detection limits and low quantitation limits of 0.017 and 0.063 µg/mL, respectively. Furthermore, the thermo-responsive magnetic molecularly imprinted polymers were successfully utilized for enriching and purifying formononetin from Trifolium pretense. The analytical results indicate that the imprinted polymers are promising materials for selective identification and enrichment of formononetin in complicated herbal medicines by simple temperature-responsive regulation.

Biotransformation and metabolic profile of anemoside B4 with rat small and large intestine microflora by ultra-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry.

Pulsatilla chinensis (Bunge) Regel is commonly used in Asia, and anemoside B4 (AB4) is its major saponin, with diverse pharmaceutical effects. Previous studies showed that intestinal flora plays an important role in the metabolism of herbs administered orally. In this study, the metabolic profile of AB4 with microflora in rat small and large intestines in vitro was investigated. Gut microflora was collected from different intestinal segments and anaerobically incubated with AB4 at 37°C for 24, 48, 72 and 96 h, respectively. A total of 10 metabolites were detected and identified by ultra- performance liquid chromatography/quadrupole time-of-flight mass spectrometry, involving the products of oxygenation and deglycosylation reactions. Gut microflora in the large intestine generated more comprehensive metabolic pathways, which appears to be attributable to the wider range of bacterial types and numbers of bacteria. Human cancer cell lines SMMC-7721, Hela and MCF-7 were treated with metabolite pools by MTT assay, together with M6 as the greatest deglycosylation product. As a result, M6 exhibited a reduction in cell viability of SMMC-7721 with an IC50 value of 22.28 ± 1.26 µg/mL. The present study provided scientific evidence for AB4 metabolism in small and large intestines, which is helpful to reveal the active forms of AB4 in vivo.

Using Quercetin to Construct Molecularly Imprinting Polymer in the Preparation and Enrichment of Flavonol and Flavonoid Compounds.

Flavonol and flavonoid compounds are important natural compounds with various biomedical activities. Therefore, it is of great significance to develop a strategy for the specific extraction of flavonol and flavonoid compounds. Quercetin is a well-studied flavonoid possessing many health benefits. This compound is a versatile antioxidant known to possess protective abilities against body tissue injury induced by pathological situations and various drug toxicities. Although quercetin is widely distributed in many plants, its content generally is not very high. Therefore, the specific extraction of quercetin as well as other flavonol and flavonoid compounds has profound significance. In this work, the quercetin molecularly imprinting polymer (QMIP) was successfully prepared, in which a typical flavonol quercetin was selected as the template molecule. QMIP was synthesized by performing the surface molecular imprinting technology on the surface of NH2-MIL-101(Fe). Our study results showed that QMIP exhibited quick binding kinetic behavior, a high adsorption capacity (57.04[Formula: see text]mg/g), and the specific recognition ability toward quercetin compared with structurally distinct compounds (selective [Formula: see text]). The specific adsorption ability of quercetin by QMIP was further explained using computation simulation that molecules with non-planar 3D conformations hardly entered the molecularly imprinted cavities on QMIP. Finally, QMIP was successfully used for the specific extraction of quercetin and five other flavonol and flavonoid compounds in the crude extracts from Sapium sebiferum. This study proposes a new strategy to synthesize the molecularly imprinted polymer based on a single template for enriching and loading a certain class of active ingredients with similar core structures from variable botanicals.

Constructing electrochemical sensor using molecular-imprinted polysaccharide for rapid identification and determination of l-tryptophan in diet.

An imbalance of l-tryptophan (l-Trp), a basic component of a healthy diet, is harmful to human health. Traditional methods for detecting l-Trp have many limitations. To correct a deficiency or excess of l-Trp in human diets, it is necessary to develop a novel method that is rapid, low-cost, and high-sensitivity. Herein, a molecularly imprinted polysaccharide electrochemical sensor termed MIP/CS/MWCNTs/GCE (molecularly imprinted polymer/chitosan/multiwalled carbon nanotubes/glassy carbon electrode) targeting l-Trp was first constructed on a glassy carbon electrode, which was modified with multiwalled carbon nanotubes and chitosan using bifunctional monomers. The MIP/CS/MWCNTs/GCE obtained a wide linear range (1-300 µM) for detecting l-Trp and accurately detected the proportion of l-Trp in mixtures of Trp enantiomers. In milk samples, the spiked recoveries of l-Trp were 86.50 to 99.65%. The MIP/CS/MWCNTs/GCE electrochemical sensor possessed good recognition and detection performance for l-Trp and has promising potential for practical application.

Swelling of Multilayered Calcium Alginate Microspheres for Drug-Loaded Dressing Induced Rapid Lidocaine Release for Better Pain Control.

The development of effective drug-loaded dressings has been considered a hot research topic for biomedical therapeutics, including the use of botanical compounds. For wound healing, adequate dressings can provide a good microenvironment for drug release, such as lidocaine. Biological macromolecular materials such as alginate show excellent properties in wound management. This study involves the preparation and evaluation of biocompatible multilayered-structure microspheres composed of chitosan, porous gelatin, and calcium alginate microspheres. The multilayered structure microspheres were named chitosan@ porous gelatin@ calcium alginate microspheres (CPAMs) and the drugs were rapidly released by the volume expansion of the calcium alginate microspheres. The in vitro release curve revealed that the peak release of lidocaine from CPAMs was reached within 18[Formula: see text]min. After 21[Formula: see text]min, the remaining lidocaine was then slowly released, and the active drug release was converted to a passive drug release phase. The initial release effect of lidocaine was much better than that reported in the published studies. Additionally, blood coagulation experiments showed that CPAMs coagulated blood in 60[Formula: see text]s, and the blood liquidity of the CPAMs group was worse than that of the woundplast group. Therefore, the coagulation characteristics of CPAMs were superior to the commonly used woundplast containing lidocaine healing gel. These study outcomes indicated that the CPAMs acted as fast-release dressings for faster pain control and better coagulation properties.

N'-(3,4-Dimeth-oxy-benzyl-idene)-3,5-dihy-droxy-benzohydrazide methanol monosolvate.

In the title compound, C(16)H(16)N(2)O(5)·CH(4)O, the two benzene rings in the Schiff base mol-ecule form a dihedral angle of 17.1 (1)°. In the crystal, inter-molecular O-H⋯O hydrogen bonds link the components into corrugated sheets parallel to the (101) plane.

Synergistic recognition of transferrin by using performance dual epitope imprinted polymers.

Transferrin (Trf) is a new type of active drug targeting carrier and disease biomarker that regulates the balance of iron ions in human body. The recognition and isolation of Trf is of great significance for disease diagnosis and treatment. Thus, a new type of magnetic dual affinity epitope molecularly imprinted polymer coated on Fe3O4 nanoparticles (Fe3O4@DEMIP) was successfully prepared for specific recognition of Trf. C-terminal nonapeptide and Trf glycan were selected as bi-epitope templates for metal chelation and boron affinity immobilization, respectively. 4-vinylphenylboric acid (4-VP), N-isopropyl acrylamide (NIPAM) and zinc acrylic were used as functional monomers. Results showed that Fe3O4@DEMIP exhibited excellent specific recognition ability adsorption capacity toward Trf, with an adsorption of 43.96 mg g-1 (RSD = 3.28%) and a more satisfactory imprinting factor (about 6.60) than that of other reported imprinting methods. In addition, Fe3O4@DEMIP displayed pH, temperature and magnetic sensitivity properties to realize temperature and pH-controlled recognition and release of target proteins and magnetic rapid separation. Furthermore, the Fe3O4@DEMIP coupled with high-performance liquid chromatography (HPLC) analysis was successfully used for specific recognition of Trf in biosamples. This study provides a reliable protocol for preparing metal chelation and boron affinity dual affinity bi-epitope molecularly imprinted polymers for synergistic and efficient recognition of biomacromolecules in the complex biological systems.

Selective separation and inexpensive purification of paclitaxel based on molecularly imprinted polymers modified with ternary deep eutectic solvents.

Paclitaxel (PTX) is a powerful anticancer natural product, with its separation and purification having been widely studied. In this work, new molecular imprinted polymers (MIPs) using deep eutectic solvents (DESs) with different molar ratios were prepared as functional monomers. These were then used as adsorbents in solid phase extraction (SPE) for the separation of PTX from its structural analogs. The polymers were characterized by energy disperive X-rays (EDX), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and fourier transform infrared spectroscopy (FT-IR). The results suggested that the formative regular DES-MIPs had an even pore-size distribution and a large specific surface area. The dynamic adsorption and static adsorption showed that the DES-MIPs had excellent adsorption performance, with a maximum adsorption capacity and optimum adsorption time of 87.08 mg/g and 180 min, respectively. The selective adsorption experiments showed that the material had outstanding selectivity, and the maximum selectivity factor was 6.20. For stability, after six consecutive adsorption and desorption cycles, the DES-MIPs maintained the perfect stability and reusability. Furthermore, the fabricated SPE column was successfully utilized for extracting and eluting PTX. This study provides a reliable protocol for the separation and purification PTX from its structural analogs and the DES-MIPs materials have excellent potential application value in pharmaceutical industry.

[The variability of vegetation beginning date of greenness period in spring in the north-south transect of eastern China based on NOAA NDVI].

NDVI based on NOAA/AVHRR from 1982 to 2003 are used to monitor variable rules for the growing season in spring of vegetation in the north-south transect of eastern China (NSTEC). The following, mainly, are included: (1) The changing speed of greenness period in spring of most regions in NSTEC is slow and correlation with the year is not distinct; (2) The regions in which greenness period in spring distinctly change mainly presented an advance; (3) The regions in which inter-annual fluctuation of greenness period in spring is over 10 days were found in 3 kinds of areas: the area covered with agricultural vegetation types; the areas covered with evergreen vegetation types; the areas covered with steppe vegetation types; (4) changes of vegetation greenness period in spring have spatio-temporal patterns.

[Spectral characteristics analysis and remote sensing inversion of water quality parameters in Han Shiqiao wetland].

The research object of the present paper is the water quality of Han Shiqiao wetland water. Water spectrum and quality parameters were measured on the site and in the lab. The authors simulated the relationships between water quality parameters and the best bands or combination, and built the multiple linear regression equation to obtain characteristic spectrum of the key water quality parameters. Besides, several key issues involved in applying ASTER satellite imagery to water quality include atmospheric correction, discussing methods for ASTER data bands analysis, and choosing the best bands and band combination. Results indicated that although the simulation model is not universal, the analysis of spectral characteristics based on ground spectrometer could provide foundations for the choice of remote sensing characteristics bands. The band ratio of water quality parameters simulated from ASTER spectral characteristics moves to relatively long-wave band. Finally, based on the analysis of ASTER remote sensing characteristics bands, the authors built water quality parameters regression model. The models for water quality parameters were recommended, and the accuracies of these models were analyzed. Making use of regression model, we executed spatial distribution map of water quality parameters to achieve wetland water monitoring with remote sensing in terms of variation in space and with time.

Extraction of activated epimedium glycosides in vivo and in vitro by using bifunctional-monomer chitosan magnetic molecularly imprinted polymers and identification by UPLC-Q-TOF-MS.

In this work, efficient, sensitive bifunctional-monomer chitosan magnetic molecularly imprinted polymers (BCMMIPs) were fabricated and successfully applied to concentrate the metabolites of Epimedium flavonoids in rat testis and bone that were later analyzed using UPLC-Q-TOF-MS. Using chitosan and methacrylic acid as co-functional monomers, BCMMIPs exhibited a large adsorption capacity (7.60 mg/g), fast kinetics (60 min), and good selectivity. Chitosan is bio-compatible and non-toxic, and methacrylic acid provides multiple hydrogen bond donors. The BCMMIPs were injected into rat testis to specifically enrich the total flavonoid metabolites in vivo and were used to extract metabolites from bone in vitro. The results showed that the BCMMIPs coupled with UPLC-Q-TOF-MS successfully identified 28 compounds from testis and 18 compounds from bone, including 19 new compounds. This study provided a reliable protocol for the concentration of metabolites from complex biological samples, and several new metabolites of Epimedium flavonoids were found in vivo and in vitro.

Simultaneous extraction of several targets by using non-toxic dual template molecularly imprinted polymers in vivo and in vitro.

In this report, a non-toxic Dual Template Molecularly Imprinted Polymers (DMIPs) was synthesized with quercetin and schisandrin b as template molecules, using deep-eutectic solvents as functional monomers for the first time. The DMIPs were used to efficiently and simultaneously enrich quercetin and schisandrin b from the mixed crude extracts of penthorum and schisandra. The results indicated that the DMIPs exhibited rapid adsorption kinetics (80 min for adsorption equilibrium) and high selectivity. The largest adsorbing capacities to quercetin and schisandrin b were 23.58 mg/g and 41.64 mg/g, respectively. After presaturation with quercetin and schisandrin b, the nontoxic saturated DMIPs were fed to the mice. Blood samples of the mice were taken and both quercetin and schisandrin b were successfully detected. The pharmacokinetics of quercetin and schisandrin b were similar to reports in the literature where mice were directly fed with botanicals. Our study provides a reliable protocol such that DMIPs can be used to separate and enrich several target molecules simultaneously from complex biological systems. Our findings suggested that the DMIPs have potential application as a drug delivery system of compound herbal formulas.

Specific adsorption of tetracycline from milk by using biocompatible magnetic molecular imprinting material and evaluation by ECD.

Biocompatible magnetic molecularly imprinted polymers (BMMIPs) were prepared with Zein for the first time, and were used to enrich tetracycline compounds selectively. Innovative combination of BMMIPs and electrochemistry to obtain lower detection line to satisfy industrial detection demands. Using Zein as the crosslinking agent, the polymers were synthesized on the surface of Fe3O4 particles. The scanning electron microscope, transmission electron microscope and X-ray diffraction technologies were used to characterize BMMIPs. Through optimization, BMMIPs attained large adsorption capacity (236.40 mg/g) with fast kinetics (40 min) and followed the Langmuir isotherm and pseudo-second-order kinetic models. BMMIPs had good recognition ability, the selective factors of oxytetracycline, chlortetracycline, doxycycline were 4.78, 4.23, and 3.39, respectively. Excellent linearity was attained in the range of 0.025-500 µg/mL, with low detection limits and low quantitation limits of 0.025 and 0.083 µg/mL. According to our exploring, BMMIPs was ideal materials for enrichment of tetracycline in complex biological samples.

Two new compounds from the marine Nigrospora sphaerica.

Two new compounds, 1-(5-oxotetrahydrofuran-2-yl)ethyl 2-phenylacetate (1) and 3-hydroxybutan-2-yl 2-hydroxy-3-phenylpropanoate (2), along with three known compounds, harzialactone A (3), benzeneethanol 4-hydroxy-1-acetate (4), and 1,4-dioxane-2,5-dione-3,6-bis(penylmethyl)-homopolymer (5), have been isolated from the fungus Nigrospora sphaerica. Their structures were determined on the basis of chemical and spectroscopic methods.

[Estimation of regional leaf area index by remote sensing inversion of PROSAIL canopy spectral model].

The present paper selected Qing yundian town and Weishanzhuang town in Da Xing District, and Gaoling ying town in Shunyi District as test areas, using MODIS data and ASTER data in different scales. The feasibility of winter wheat LAI inversion by PROSAIL physical model, especially the stability of remote sensing data in different scales, was discussed, and the results from experience model inversion were compared with that from statistical methods. The values of all samples LAI inversion from experience model are close in a region, which means experience model is a reflection of general growing trend, ignoring spatial heterogeneity of the regional leaf area index. But the value of LAI inversion from physical model can be truer in reflecting spatial heterogeneity of the regional leaf area index. The value of LAI inversion from physical model is more real, compared with experience model. With the method of linear weighing, the scale conversion was accomplished, and the LAI inversion results from different remote sensing scale data were compared, and were found similar. The result shows that in the process of large-scale regional LAI inversion, physical model inversion is more valid.

6,8-di-C-glycosyl flavones with ß-furanoarabinose from Scutellaria baicalensis and their anti-inflammatory activities.

Two flavone di-C-glycosides, a pair of isomers, were isolated from Scutellaria baicalensis. The structures of compounds 1 and 2 were elucidated by means of physical data, including 1D and 2D NMR and HR-ESI-MS. Supporting theoretical calculations of the compound conformational landscape has also been conducted for geometry optimization. This is the first report of the natural occurrence of ß-furanoarabinoside. In addition, the effects of compounds 1 and 2 on NO, pro-inflammatory cytokines, PGE2 and COX-2 levels were measured in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage cells. The pair of isomers exhibited significant inhibitory effects on inflammation.