Login In
2015 Volume 26 Issue 12
2015, 26(12): 1435-1438
doi: 10.1016/j.cclet.2015.10.019
Abstract:
The past years have witnessed a rapid development of DNA nanotechnology in nanomaterials science with a central focus on programmable material construction on the nanoscale. An efficient method is therefore highly desirable (but challenging) for analytical/preparative purification of DNA-conjugated nano-objects and their DNA-assemblies. In this regard, agarose gel electrophoresis, a traditional technique that has been invented for biomacromolecule separation, has found many innovative uses. This includes shape, size, charge, and ligand-valence separations of nanoparticle building blocks as well as monitoring a self-assembly process towards product identification and purification.
The past years have witnessed a rapid development of DNA nanotechnology in nanomaterials science with a central focus on programmable material construction on the nanoscale. An efficient method is therefore highly desirable (but challenging) for analytical/preparative purification of DNA-conjugated nano-objects and their DNA-assemblies. In this regard, agarose gel electrophoresis, a traditional technique that has been invented for biomacromolecule separation, has found many innovative uses. This includes shape, size, charge, and ligand-valence separations of nanoparticle building blocks as well as monitoring a self-assembly process towards product identification and purification.
2015, 26(12): 1439-1445
doi: 10.1016/j.cclet.2015.10.014
Abstract:
Metal-organic frameworks (MOFs) are a fascinating class of crystalline materials constructed from selfassembly of metal cations/clusters and organic ligands. Both metal and organic components can be used to generate luminescence, and can further interact via antenna effect to increase the quantum yield, providing a versatile platform for chemical sensing based on luminescence emission. Moreover, MOFs can be miniaturized to nanometer scale to form nano-MOF (NMOF) materials, which exhibit many advantages over conventional bulk MOFs in terms of the facile tailorability of compositions, sizes and morphologies, the high dispersity in a wide variety of medium, and the intrinsic biocompatibility. This review will detail the development of NMOF materials as chemical sensors, including the synthetic methodologies for designing NMOF sensory materials, their luminescent properties and potential sensing applications.
Metal-organic frameworks (MOFs) are a fascinating class of crystalline materials constructed from selfassembly of metal cations/clusters and organic ligands. Both metal and organic components can be used to generate luminescence, and can further interact via antenna effect to increase the quantum yield, providing a versatile platform for chemical sensing based on luminescence emission. Moreover, MOFs can be miniaturized to nanometer scale to form nano-MOF (NMOF) materials, which exhibit many advantages over conventional bulk MOFs in terms of the facile tailorability of compositions, sizes and morphologies, the high dispersity in a wide variety of medium, and the intrinsic biocompatibility. This review will detail the development of NMOF materials as chemical sensors, including the synthetic methodologies for designing NMOF sensory materials, their luminescent properties and potential sensing applications.
2015, 26(12): 1446-1449
doi: 10.1016/j.cclet.2015.07.015
Abstract:
A novel method is developed for the direct determination of naphazoline hydrochloride (NAP) and pyridoxine hydrochloride (VB6) in commercial eye drops. By using excitation-emission matrix (EEM) fluorescence coupled with second-order calibration method based on the alternating trilinear decomposition (ATLD) algorithm, the proposed approach can achieve quantitative analysis successfully even in the presence of unknown and uncalibrated interferences. The method shows good linearity for NAP and VB6 with correlation coefficients greater than 0.99. The results were in good agreement with the labeled contents. To further confirm the feasibility and reliability of the proposed method, the same batch samples were analyzed by multiple reaction monitoring (MRM) based on LC-MS/MS method. T-test demonstrated that there are no significant differences between the prediction results of the two methods. The satisfactory results obtained in this work indicate that the use of the second-order calibration method coupled with the EEM is a promising tool for industrial quality control and pharmaceutical analysis due to its advantages of high sensitivity, low-cost and simple implementation.
A novel method is developed for the direct determination of naphazoline hydrochloride (NAP) and pyridoxine hydrochloride (VB6) in commercial eye drops. By using excitation-emission matrix (EEM) fluorescence coupled with second-order calibration method based on the alternating trilinear decomposition (ATLD) algorithm, the proposed approach can achieve quantitative analysis successfully even in the presence of unknown and uncalibrated interferences. The method shows good linearity for NAP and VB6 with correlation coefficients greater than 0.99. The results were in good agreement with the labeled contents. To further confirm the feasibility and reliability of the proposed method, the same batch samples were analyzed by multiple reaction monitoring (MRM) based on LC-MS/MS method. T-test demonstrated that there are no significant differences between the prediction results of the two methods. The satisfactory results obtained in this work indicate that the use of the second-order calibration method coupled with the EEM is a promising tool for industrial quality control and pharmaceutical analysis due to its advantages of high sensitivity, low-cost and simple implementation.
2015, 26(12): 1450-1454
doi: 10.1016/j.cclet.2015.10.016
Abstract:
Single cell analysis is of great significance to understand the physiological activity of organisms. Microfluidic droplet is an ideal analytical platform for single-cell analysis. We developed a microfluidic droplet splitting system integrated with a flow-focusing structure and multi-step splitting structures to form 8-line droplets and encapsulate single cells in the droplets. Droplet generation frequency reached 1021 Hz with the aqueous phase flow rate of 1 μL/min and the oil phase flow rate of 15 μL/min. Relative standard deviation of the droplet size was less than 5% in a single channel, while less than 6% in all the 8 channels. The system was used for encapsulating human whole blood cells. A single-cell encapsulation efficiency of 31% was obtained with the blood cell concentration of 2.5×104 cells/μL, and the multicellular droplet percentage was only 1.3%. The multi-step droplet splitting system for single cell encapsulation featured simple structure and high throughput.
Single cell analysis is of great significance to understand the physiological activity of organisms. Microfluidic droplet is an ideal analytical platform for single-cell analysis. We developed a microfluidic droplet splitting system integrated with a flow-focusing structure and multi-step splitting structures to form 8-line droplets and encapsulate single cells in the droplets. Droplet generation frequency reached 1021 Hz with the aqueous phase flow rate of 1 μL/min and the oil phase flow rate of 15 μL/min. Relative standard deviation of the droplet size was less than 5% in a single channel, while less than 6% in all the 8 channels. The system was used for encapsulating human whole blood cells. A single-cell encapsulation efficiency of 31% was obtained with the blood cell concentration of 2.5×104 cells/μL, and the multicellular droplet percentage was only 1.3%. The multi-step droplet splitting system for single cell encapsulation featured simple structure and high throughput.
2015, 26(12): 1455-1459
doi: 10.1016/j.cclet.2015.10.015
Abstract:
Surface-enhanced Raman scattering (SERS) is applied to detect the concentration of carbendzim (CBZ) in tea leaves. Au colloid is selected and used for active surfaces, and the extraction conditions are optimized in the experiment. The linearity range for the SERS intensity and the concentration of CBZ is found to be 0.5 to 8 mg kg-1. The detection limit for CBZ is 0.1 mg kg-1 and its recovery in tea samples is 72.3%. The detection results for CBZ using this method are compared with those of HPLC, and no obvious difference can be found. In addition, by dripping the condensed Au colloid on the tea leaves, the proposed SERS approach could be used to the in-situ determination of the half life period of CBZ on tea leaves.
Surface-enhanced Raman scattering (SERS) is applied to detect the concentration of carbendzim (CBZ) in tea leaves. Au colloid is selected and used for active surfaces, and the extraction conditions are optimized in the experiment. The linearity range for the SERS intensity and the concentration of CBZ is found to be 0.5 to 8 mg kg-1. The detection limit for CBZ is 0.1 mg kg-1 and its recovery in tea samples is 72.3%. The detection results for CBZ using this method are compared with those of HPLC, and no obvious difference can be found. In addition, by dripping the condensed Au colloid on the tea leaves, the proposed SERS approach could be used to the in-situ determination of the half life period of CBZ on tea leaves.
2015, 26(12): 1460-1464
doi: 10.1016/j.cclet.2015.10.013
Abstract:
The hierarchical metal-organic frameworks (MOFs), such as Y(BTC)(H2O)6, are prepared with yttrium nitrate and benzene-1,3,5-tricarboxylic acid at room temperature. The product is characterized by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The Y(BTC)(H2O)6 particles are sufficiently rigid for performing solid phase extraction and they exhibit favorable selectivity toward the adsorption of hemoglobin. The adsorption behavior of hemoglobin onto the Y(BTC)(H2O)6 fits the Langmuir adsorption model with a theoretical adsorption capacity of 555.6 mg g-1 . An adsorption efficiency of 87.7% for 100 μgmL-1 hemoglobin in 1 mL sample solution (at pH 6.0) is achieved with 0.40 mg Y(BTC)(H2O)6. 77.3% of the retained hemoglobin is readily recovered using a 0.5% (m/v) SDS solution as the stripping reagent. Circular dichroism spectra indicated that the conformation of hemoglobin is maintained during the adsorption-desorption process. The MOFs material is applied for the isolation of hemoglobin from human blood and the purity of the obtained hemoglobin is further verified by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE).
The hierarchical metal-organic frameworks (MOFs), such as Y(BTC)(H2O)6, are prepared with yttrium nitrate and benzene-1,3,5-tricarboxylic acid at room temperature. The product is characterized by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The Y(BTC)(H2O)6 particles are sufficiently rigid for performing solid phase extraction and they exhibit favorable selectivity toward the adsorption of hemoglobin. The adsorption behavior of hemoglobin onto the Y(BTC)(H2O)6 fits the Langmuir adsorption model with a theoretical adsorption capacity of 555.6 mg g-1 . An adsorption efficiency of 87.7% for 100 μgmL-1 hemoglobin in 1 mL sample solution (at pH 6.0) is achieved with 0.40 mg Y(BTC)(H2O)6. 77.3% of the retained hemoglobin is readily recovered using a 0.5% (m/v) SDS solution as the stripping reagent. Circular dichroism spectra indicated that the conformation of hemoglobin is maintained during the adsorption-desorption process. The MOFs material is applied for the isolation of hemoglobin from human blood and the purity of the obtained hemoglobin is further verified by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE).
2015, 26(12): 1465-1469
doi: 10.1016/j.cclet.2015.10.022
Abstract:
The rapid and reliable measurement of hydrogen peroxide (H2O2) is imperative for many areas of technology, including pharmaceutical, clinical, food industry and environmental applications. In this work, a novel multifunctional complex, [Ru(bpy)2(luminol-bpy)](PF6)2 (bpy: 2,20'-bipyridine), was designed and synthesized by incorporating a Ru(II) complex with a luminal group. In the presence of horseradish peroxidase (HRP), reaction of [Ru(bpy)2(luminol-bpy)]2+ with H2O2 can be monitored by three sensing channels including photoluminescence (PL), chemiluminiscence (CL) and eletrochemiluminiscence (ECL). The quantitative assays for H2O2 in aqueous solutions using [Ru(bpy)2(Luminalbpy)]( PF6)2 as a probe were established with PL, ECL and CL signal output modes, respectively.
The rapid and reliable measurement of hydrogen peroxide (H2O2) is imperative for many areas of technology, including pharmaceutical, clinical, food industry and environmental applications. In this work, a novel multifunctional complex, [Ru(bpy)2(luminol-bpy)](PF6)2 (bpy: 2,20'-bipyridine), was designed and synthesized by incorporating a Ru(II) complex with a luminal group. In the presence of horseradish peroxidase (HRP), reaction of [Ru(bpy)2(luminol-bpy)]2+ with H2O2 can be monitored by three sensing channels including photoluminescence (PL), chemiluminiscence (CL) and eletrochemiluminiscence (ECL). The quantitative assays for H2O2 in aqueous solutions using [Ru(bpy)2(Luminalbpy)]( PF6)2 as a probe were established with PL, ECL and CL signal output modes, respectively.
2015, 26(12): 1470-1477
doi: 10.1016/j.cclet.2015.10.023
Abstract:
A novel on-line solid-phase microextraction-high-performance liquid chromatography (SPME-HPLC) system was developed for the determination of heterocyclic aromatic amines (HAAs) in food samples. A poly(vinylphenylboronic acid-co-ethylene glycol dimethacrylate) polymer monolith was prepared for on-line efficient extraction and large-volume injection was used to increase the sensitivity of detection. The polymermonolith, based on a ternary porogen, was prepared by in situ polymerization of vinylphenylboronic acid (VPBA) and ethylene glycol dimethacrylate (EGDMA) in a fused-silica capillary column. It showed good permeability, high extraction capacity, and high selectivity. The column-tocolumn reproducibility was satisfactory, and the enrichment factors for HAAs were 3746-7414. Conditions influencing the on-line extraction efficiency, including pH of sample solutions, flow rate of extraction and desorption, and desorption volume, were investigated. The proposed method had low limit of detection (0.10-0.15 ng/L) and good linearity. Trace HAAs in roast beef and lamb samples were determined, and the amounts of 2-amino-3-methylimidazo[4,5-f]quinoline, 2-amino-3,4-dimethylimidazo[4,5-f]quinoline, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline, 2-amino-3,4,8-trimethylimidazo[ 4,5-f]quinoxaline, and 2-amino-3,4,7,8-tetramethyl-3H-imidazo[4,5-f]quinoxaline in these samples were 0.235-2.08 ng/g. The recoveries for the five HAAs ranged from74.3% to 119%, and the relative standard deviation (RSDs) were less than 8.2%. The results showed that the proposed on-line method was highly sensitive for monitoring HAAs in different food samples.
A novel on-line solid-phase microextraction-high-performance liquid chromatography (SPME-HPLC) system was developed for the determination of heterocyclic aromatic amines (HAAs) in food samples. A poly(vinylphenylboronic acid-co-ethylene glycol dimethacrylate) polymer monolith was prepared for on-line efficient extraction and large-volume injection was used to increase the sensitivity of detection. The polymermonolith, based on a ternary porogen, was prepared by in situ polymerization of vinylphenylboronic acid (VPBA) and ethylene glycol dimethacrylate (EGDMA) in a fused-silica capillary column. It showed good permeability, high extraction capacity, and high selectivity. The column-tocolumn reproducibility was satisfactory, and the enrichment factors for HAAs were 3746-7414. Conditions influencing the on-line extraction efficiency, including pH of sample solutions, flow rate of extraction and desorption, and desorption volume, were investigated. The proposed method had low limit of detection (0.10-0.15 ng/L) and good linearity. Trace HAAs in roast beef and lamb samples were determined, and the amounts of 2-amino-3-methylimidazo[4,5-f]quinoline, 2-amino-3,4-dimethylimidazo[4,5-f]quinoline, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline, 2-amino-3,4,8-trimethylimidazo[ 4,5-f]quinoxaline, and 2-amino-3,4,7,8-tetramethyl-3H-imidazo[4,5-f]quinoxaline in these samples were 0.235-2.08 ng/g. The recoveries for the five HAAs ranged from74.3% to 119%, and the relative standard deviation (RSDs) were less than 8.2%. The results showed that the proposed on-line method was highly sensitive for monitoring HAAs in different food samples.
2015, 26(12): 1478-1484
doi: 10.1016/j.cclet.2015.10.026
Abstract:
Heterojunction Fe2O3 nanoparticles (NPs), NiFe2O4 nanofibers (NFs), and CoFe2O4 NFs were synthesized by electrospinning and the subsequent thermal treatment processes. Characterization results indeed display the three-dimensional net-like textural structures of these as-electrospun spinel-type MFe2O4 NFs. The MFe2O4 NFs-based film configurations possess abundant micro/meso/macropores on their surface. These structures could afford more accessible transport channels for effective reduction of the mass transport resistance and improvement of the density of exposed catalytic active sites. All these advantages are responsible for the enhanced electro-catalytic performance of these MFe2O4 NFs in hydrazine oxidation. When used for hydrazine detection, CoFe2O4 NFs show the best catalytic efficiency. For example, the CoFe2O4 NFs possess a large sensitivity of 1327 μA cm-2 (mmol L-1)-1 in the linear range of 0.01 to 0.1 mmol L-1 and 503 μA cm-2 (mmol L-1) 1 in the linear range of 0.1 to 11 mmol L 1, a response time of shorter than 3 s, good reproducibility and remarkable long-term stability. The superior catalytic efficiency, excellent stability, low cost, and ease of fabrication render CoFe2O4 NFs very promising materials in developing an electrochemical device that directly detects hydrazine.
Heterojunction Fe2O3 nanoparticles (NPs), NiFe2O4 nanofibers (NFs), and CoFe2O4 NFs were synthesized by electrospinning and the subsequent thermal treatment processes. Characterization results indeed display the three-dimensional net-like textural structures of these as-electrospun spinel-type MFe2O4 NFs. The MFe2O4 NFs-based film configurations possess abundant micro/meso/macropores on their surface. These structures could afford more accessible transport channels for effective reduction of the mass transport resistance and improvement of the density of exposed catalytic active sites. All these advantages are responsible for the enhanced electro-catalytic performance of these MFe2O4 NFs in hydrazine oxidation. When used for hydrazine detection, CoFe2O4 NFs show the best catalytic efficiency. For example, the CoFe2O4 NFs possess a large sensitivity of 1327 μA cm-2 (mmol L-1)-1 in the linear range of 0.01 to 0.1 mmol L-1 and 503 μA cm-2 (mmol L-1) 1 in the linear range of 0.1 to 11 mmol L 1, a response time of shorter than 3 s, good reproducibility and remarkable long-term stability. The superior catalytic efficiency, excellent stability, low cost, and ease of fabrication render CoFe2O4 NFs very promising materials in developing an electrochemical device that directly detects hydrazine.
2015, 26(12): 1485-1489
doi: 10.1016/j.cclet.2015.10.021
Abstract:
Lanthanide complex-based luminescent probes/chemosensors have shown great utilities in various biological and environmental assays with time-resolved detection mode to eliminate background noises. In this work, by conjugating di(2-picolyl)amine (DPA) with a tetradentate β-diketone 1,2-bis[4'- (1",1",1",2",2"-pentafluoro-3",5"-pentanedion-5"-yl)benzyl]-4-chlorosulfo-benzene (BPPBCB), a novel dual-functional ligand that can coordinate to Eu3+ for responding to Cu2+ and S2- ions in aqueous media, DPA-BPPBCB, has been designed and synthesized. The β-diketone moiety of DPA-BPPBCB can form a strongly luminescent complex with Eu3+. Upon reaction with Cu2+, accompanied by the formation of heterobimetallic complex Cu2+-DPA-BPPBCB-Eu3+, the Eu3+ luminescence was quenched. While in the presence of S2-, owing to the high affinity of S2- to Cu2+, stable CuS was formed, which resulted in the release of Cu2+ from Cu2+-DPA-BPPBCB-Eu3+, to restore the luminescence of the Eu3+ complex. This unique “on-off-on” luminescence response of the Eu3+ complex enabled Cu2+ and S2- ions in aqueous media to be detected with time-resolved luminescence detection mode.
Lanthanide complex-based luminescent probes/chemosensors have shown great utilities in various biological and environmental assays with time-resolved detection mode to eliminate background noises. In this work, by conjugating di(2-picolyl)amine (DPA) with a tetradentate β-diketone 1,2-bis[4'- (1",1",1",2",2"-pentafluoro-3",5"-pentanedion-5"-yl)benzyl]-4-chlorosulfo-benzene (BPPBCB), a novel dual-functional ligand that can coordinate to Eu3+ for responding to Cu2+ and S2- ions in aqueous media, DPA-BPPBCB, has been designed and synthesized. The β-diketone moiety of DPA-BPPBCB can form a strongly luminescent complex with Eu3+. Upon reaction with Cu2+, accompanied by the formation of heterobimetallic complex Cu2+-DPA-BPPBCB-Eu3+, the Eu3+ luminescence was quenched. While in the presence of S2-, owing to the high affinity of S2- to Cu2+, stable CuS was formed, which resulted in the release of Cu2+ from Cu2+-DPA-BPPBCB-Eu3+, to restore the luminescence of the Eu3+ complex. This unique “on-off-on” luminescence response of the Eu3+ complex enabled Cu2+ and S2- ions in aqueous media to be detected with time-resolved luminescence detection mode.
2015, 26(12): 1490-1495
doi: 10.1016/j.cclet.2015.10.017
Abstract:
Precise fluorescence imaging of single λ-DNA molecules for base pair distance analysis requires a superresolution technique, as these distances are on the order of diffraction limit. Individual λ-DNA molecules intercalated with the fluorescent dye YOYO-1 were investigated at subdiffraction spatial resolution by direct stochastic optical reconstructionmicroscopy (dSTORM). Various dye-to-DNA base pair ratios were imaged by photoswitching YOYO-1 between the fluorescent state and the dark state using two laser sources. The acquired images were reconstructed into a super-resolution image by applying Gaussian fitting to the centroid of the point spread function. By measuring the distances between localized fluorophores, the base pair distances in single DNA molecules for dye-to-DNA base pair ratios of 1:50, 1:100, and 1:500 were calculated to be 17.1±0.8 nm, 34.3±2.2 nm, and 170.3±8.1 nm, respectively, which were in agreement with theoretical values. These results demonstrate that intercalating dye in a single DNA molecule can be photoswitched without the use of an activator fluorophore, and that super-localization precision at a spatial resolution of ~17 nm was experimentally achieved.
Precise fluorescence imaging of single λ-DNA molecules for base pair distance analysis requires a superresolution technique, as these distances are on the order of diffraction limit. Individual λ-DNA molecules intercalated with the fluorescent dye YOYO-1 were investigated at subdiffraction spatial resolution by direct stochastic optical reconstructionmicroscopy (dSTORM). Various dye-to-DNA base pair ratios were imaged by photoswitching YOYO-1 between the fluorescent state and the dark state using two laser sources. The acquired images were reconstructed into a super-resolution image by applying Gaussian fitting to the centroid of the point spread function. By measuring the distances between localized fluorophores, the base pair distances in single DNA molecules for dye-to-DNA base pair ratios of 1:50, 1:100, and 1:500 were calculated to be 17.1±0.8 nm, 34.3±2.2 nm, and 170.3±8.1 nm, respectively, which were in agreement with theoretical values. These results demonstrate that intercalating dye in a single DNA molecule can be photoswitched without the use of an activator fluorophore, and that super-localization precision at a spatial resolution of ~17 nm was experimentally achieved.
2015, 26(12): 1496-1501
doi: 10.1016/j.cclet.2015.10.018
Abstract:
Carbon dots are prepared and immobilized onto spherical SiO2 through a one-step thermal oxidation and then decorated with metallothionein (MT), a protein with high affinity towards thiophilic metals. The MT-carbon dots composites are characterized by means of FT-IR, SEM and TGA, giving rise to a MT loading amount of 823 μg g-1. The adsorption of cadmium by the composites is a fast process and follows Langmuir model. In comparison with native SiO2, a 2- and 2.4-folds improvement on the static and dynamic adsorption capacity of the composites for cadmium are obtained, respectively. Moreover, the adsorption efficiency is not affected by the presence of other metals. Finally, the composites are successfully applied for the removal of cadmium in a series of environmental water samples.
Carbon dots are prepared and immobilized onto spherical SiO2 through a one-step thermal oxidation and then decorated with metallothionein (MT), a protein with high affinity towards thiophilic metals. The MT-carbon dots composites are characterized by means of FT-IR, SEM and TGA, giving rise to a MT loading amount of 823 μg g-1. The adsorption of cadmium by the composites is a fast process and follows Langmuir model. In comparison with native SiO2, a 2- and 2.4-folds improvement on the static and dynamic adsorption capacity of the composites for cadmium are obtained, respectively. Moreover, the adsorption efficiency is not affected by the presence of other metals. Finally, the composites are successfully applied for the removal of cadmium in a series of environmental water samples.
2015, 26(12): 1502-1506
doi: 10.1016/j.cclet.2015.10.024
Abstract:
To discover new chemotypes of nematicides with proper toxicological profiles, a series of novel 1,2,3- benzotriazin-4-one derivatives were synthesized and further bioevaluated. The bioassay results showed that most of the synthesized compounds were endowed with moderate to good control efficacy against Meloidogyne incognita at 10.0 mg/L in vivo. Among them, compounds 6k and 6p displayed 100% inhibitory activities at this concentration, which implied that they could be used as lead compounds for promising nematicides.
To discover new chemotypes of nematicides with proper toxicological profiles, a series of novel 1,2,3- benzotriazin-4-one derivatives were synthesized and further bioevaluated. The bioassay results showed that most of the synthesized compounds were endowed with moderate to good control efficacy against Meloidogyne incognita at 10.0 mg/L in vivo. Among them, compounds 6k and 6p displayed 100% inhibitory activities at this concentration, which implied that they could be used as lead compounds for promising nematicides.
Stereochemical determination of tetrahydropyran-substituted xanthones from fungus Chaetomium murorum
2015, 26(12): 1507-1510
doi: 10.1016/j.cclet.2015.10.025
Abstract:
Chaetoxanthone D (1), a new tetrahydropyran-substituted xanthone originated from polyketide pathway, together with the four known natural products chaetoxanthone C (2), alternariol methyl ether (3), alternariol (4) and 2,5-dimethyl-7-hydroxychromone (5) was isolated from a strain of Chaetomium murorum. The structures of these compounds were elucidated based on extensive spectroscopic analyses. The absolute configurations of 1 and 2 were determined by using quantum chemical electronic circular dichroism (ECD) calculations.
Chaetoxanthone D (1), a new tetrahydropyran-substituted xanthone originated from polyketide pathway, together with the four known natural products chaetoxanthone C (2), alternariol methyl ether (3), alternariol (4) and 2,5-dimethyl-7-hydroxychromone (5) was isolated from a strain of Chaetomium murorum. The structures of these compounds were elucidated based on extensive spectroscopic analyses. The absolute configurations of 1 and 2 were determined by using quantum chemical electronic circular dichroism (ECD) calculations.
2015, 26(12): 1511-1513
doi: 10.1016/j.cclet.2015.07.024
Abstract:
A series of novel imidazo[1,2-b]isoxazoles 3 and their Mannich bases 4-6 were synthesized via convenient reactions. The reaction of 3-aminoisoxazole 1 with substituted phenacyl bromides 2 in dry ethanol afforded the corresponding 6-methyl-3-aryl imidazo[1,2-b]isoxazoles 3 in good yields. Compounds 3 on treatment with 37% formaline and secondary amines furnished the corresponding novel Mannich bases viz., 6-methyl-3-aryl-2-(morpholine/pyrrolidin-1-yl/piperidin-1-yl)-methyl-imidazo[ 1,2-b]isoxazoles 4-6.
A series of novel imidazo[1,2-b]isoxazoles 3 and their Mannich bases 4-6 were synthesized via convenient reactions. The reaction of 3-aminoisoxazole 1 with substituted phenacyl bromides 2 in dry ethanol afforded the corresponding 6-methyl-3-aryl imidazo[1,2-b]isoxazoles 3 in good yields. Compounds 3 on treatment with 37% formaline and secondary amines furnished the corresponding novel Mannich bases viz., 6-methyl-3-aryl-2-(morpholine/pyrrolidin-1-yl/piperidin-1-yl)-methyl-imidazo[ 1,2-b]isoxazoles 4-6.
2015, 26(12): 1514-1517
doi: 10.1016/j.cclet.2015.09.013
Abstract:
Single molecule catalysis is very powerful in revealing catalytic mechanism at the single molecule level. But fluorescentmolecule is always necessary to take part into the catalysis directly in previous research. In order to study the single molecule electro-catalysis of non-fluorescentmolecule (SMECNFM) on nanocatalyst, we couple the SMECNFM with a single molecule fluorescence reaction. A certain number of fluorescent molecules will be generated and detected when the SMECNFM happens. Through this method, we can detect the electro-oxidation reaction of one HCOONamolecule. The stability of Pt nanocatalyst supported on active carbon is studied at the singlemolecule level by this method. This paper also provides a general way to make ultra-sensitive sensor, and to study the SMECNFM for the molecules, such as formic acid, hydrogen, oxygen, etc., on single nanoparticle.
Single molecule catalysis is very powerful in revealing catalytic mechanism at the single molecule level. But fluorescentmolecule is always necessary to take part into the catalysis directly in previous research. In order to study the single molecule electro-catalysis of non-fluorescentmolecule (SMECNFM) on nanocatalyst, we couple the SMECNFM with a single molecule fluorescence reaction. A certain number of fluorescent molecules will be generated and detected when the SMECNFM happens. Through this method, we can detect the electro-oxidation reaction of one HCOONamolecule. The stability of Pt nanocatalyst supported on active carbon is studied at the singlemolecule level by this method. This paper also provides a general way to make ultra-sensitive sensor, and to study the SMECNFM for the molecules, such as formic acid, hydrogen, oxygen, etc., on single nanoparticle.
2015, 26(12): 1518-1521
doi: 10.1016/j.cclet.2015.09.022
Abstract:
A fast-growing procedure (FGP) to fabricate perovskite films with large grain sizes is described in this article. In the FGP method, the perovskite precursor solution is coated onto the substrates at a temperature of ~240 ℃. The solvent in the precursor solution evaporates quickly in about 2 s, resulting in the rapid formation of a perovskite film without further annealing process. Millimeter-scale perovskite grain clusters are obtained in the film. Based on such perovskite films, fabricated planar heterojunction perovskite solar cells give a power conversion efficiency (PCE) above 8%.
A fast-growing procedure (FGP) to fabricate perovskite films with large grain sizes is described in this article. In the FGP method, the perovskite precursor solution is coated onto the substrates at a temperature of ~240 ℃. The solvent in the precursor solution evaporates quickly in about 2 s, resulting in the rapid formation of a perovskite film without further annealing process. Millimeter-scale perovskite grain clusters are obtained in the film. Based on such perovskite films, fabricated planar heterojunction perovskite solar cells give a power conversion efficiency (PCE) above 8%.
2015, 26(12): 1522-1528
doi: 10.1016/j.cclet.2015.09.004
Abstract:
New series of benzothiazole derivatives were designed and synthesized. The newly synthesized compounds were screened for their antibacterial activity against Escherichia coli, Staphylococcus aureus and Bacillus cereus. Compounds 6j and 6o showed the highest activity against E. coli and S. aureus. The antifungal activity of these compounds was also tested against Candida albicans and Aspergillus fumigatus 293. Compounds 4c, 4g and 6j exhibited the highest activity against C. albicans. In addition, compounds 4a and 6j displayed promising activity against A. fumigatus 293. The same compounds were examined for their antiquorum-sensing activity against Chromobacteriumviolaceum ATCC 12472, whereas compounds 4a, 6j and 6p showed moderate activity. The in vitro cytotoxicity testing of the synthesized compounds was performed against cervical cancer (Hela) and kidney fibroblast cancer (COS-7) cell lines. Results indicated that all tested compounds have IC50 values > 50 μmol/L against both cell lines. Molecular properties, toxicities, drug-likeness, and drug score profiles of compounds 4a-c, 5a, 6g,h, 6j, 6l, 6o and 7c,d were also assessed.
New series of benzothiazole derivatives were designed and synthesized. The newly synthesized compounds were screened for their antibacterial activity against Escherichia coli, Staphylococcus aureus and Bacillus cereus. Compounds 6j and 6o showed the highest activity against E. coli and S. aureus. The antifungal activity of these compounds was also tested against Candida albicans and Aspergillus fumigatus 293. Compounds 4c, 4g and 6j exhibited the highest activity against C. albicans. In addition, compounds 4a and 6j displayed promising activity against A. fumigatus 293. The same compounds were examined for their antiquorum-sensing activity against Chromobacteriumviolaceum ATCC 12472, whereas compounds 4a, 6j and 6p showed moderate activity. The in vitro cytotoxicity testing of the synthesized compounds was performed against cervical cancer (Hela) and kidney fibroblast cancer (COS-7) cell lines. Results indicated that all tested compounds have IC50 values > 50 μmol/L against both cell lines. Molecular properties, toxicities, drug-likeness, and drug score profiles of compounds 4a-c, 5a, 6g,h, 6j, 6l, 6o and 7c,d were also assessed.
2015, 26(12): 1529-1534
doi: 10.1016/j.cclet.2015.06.009
Abstract:
Li4Ti5O12 (LTO)/carbon nanotubes (CNTs) composite material is synthesized based on a solid-state method by sand-milling, spray-drying and calcining at 850 ℃ under N2 flow. The LTO/CNTs samples with 1 wt% and 3 wt% weight ratio of CNTs addition and the pristine LTO sample are prepared. The rate performance and the thermal stability of these samples are investigated based on LiMn2O4 (LMO)/LTO full-cell. The results show that theweight ratio of CNTs addition has distinct effect on LTO performances. The composite materials of LTO composited CNTs have better performance at high-rate due to the intercalation enhancement by conductive network of CNTs. At second, the overcharging temperature response of the cell's surface with 1 wt% CNTs addition is the lowest. The particle size distribution is measured and the most uniform particles are obtained with 1 wt% CNTs addition. This trend could explain that the mediumquantity of CNTs is optimal to improve the heat and mass transfer and prevent the problems of crystallite growing interference and aggregation during the calcination process.
Li4Ti5O12 (LTO)/carbon nanotubes (CNTs) composite material is synthesized based on a solid-state method by sand-milling, spray-drying and calcining at 850 ℃ under N2 flow. The LTO/CNTs samples with 1 wt% and 3 wt% weight ratio of CNTs addition and the pristine LTO sample are prepared. The rate performance and the thermal stability of these samples are investigated based on LiMn2O4 (LMO)/LTO full-cell. The results show that theweight ratio of CNTs addition has distinct effect on LTO performances. The composite materials of LTO composited CNTs have better performance at high-rate due to the intercalation enhancement by conductive network of CNTs. At second, the overcharging temperature response of the cell's surface with 1 wt% CNTs addition is the lowest. The particle size distribution is measured and the most uniform particles are obtained with 1 wt% CNTs addition. This trend could explain that the mediumquantity of CNTs is optimal to improve the heat and mass transfer and prevent the problems of crystallite growing interference and aggregation during the calcination process.
2015, 26(12): 1535-1537
doi: 10.1016/j.cclet.2015.07.017
Abstract:
In this article, nano-scale Al/Fe2O3 composites with different morphologies were successfully obtained by a simple electrospinning technique, which is based on a surfactant (polyvinyl pyridine, PVP) in a mixture of N,N-dimethylformamide (DMF) and 2-propanol. The electrospun Al/Fe2O3 composites exhibited a crystal structure and phase composition by X-ray diffraction analysis. The different morphologies of the Al/Fe2O3 composites were also observed through scanning electron microscopy and transmission electron microscopy. It was found that the rather simple electrospinning method used to prepare the morphology-controlled Al/Fe2O3 composites may have the potential for preparation of propellants, explosives, and pyrotechnics in the future.
In this article, nano-scale Al/Fe2O3 composites with different morphologies were successfully obtained by a simple electrospinning technique, which is based on a surfactant (polyvinyl pyridine, PVP) in a mixture of N,N-dimethylformamide (DMF) and 2-propanol. The electrospun Al/Fe2O3 composites exhibited a crystal structure and phase composition by X-ray diffraction analysis. The different morphologies of the Al/Fe2O3 composites were also observed through scanning electron microscopy and transmission electron microscopy. It was found that the rather simple electrospinning method used to prepare the morphology-controlled Al/Fe2O3 composites may have the potential for preparation of propellants, explosives, and pyrotechnics in the future.
2015, 26(12): 1538-1541
doi: 10.1016/j.cclet.2015.09.007
Abstract:
One new sesquiterpene compound, namely, illihenlactone A (1), and one new prenylated C6-C3 compound, illihenryione H (2), along with three known sesquiterpenes (3-5) were isolated from the stems of Illicium henryi. The structures of 1 and 2 were elucidated by spectroscopic evidence including NMR, HRESIMS and circular dichroism (CD). Compound 2 exhibited a weak inhibitory ratio for β-glucuronidase release induced by platelet-activating factor (PAF) in rat polymorphonuclear leukocytes (PMNs) in vitro.
One new sesquiterpene compound, namely, illihenlactone A (1), and one new prenylated C6-C3 compound, illihenryione H (2), along with three known sesquiterpenes (3-5) were isolated from the stems of Illicium henryi. The structures of 1 and 2 were elucidated by spectroscopic evidence including NMR, HRESIMS and circular dichroism (CD). Compound 2 exhibited a weak inhibitory ratio for β-glucuronidase release induced by platelet-activating factor (PAF) in rat polymorphonuclear leukocytes (PMNs) in vitro.
2015, 26(12): 1542-1546
doi: 10.1016/j.cclet.2015.10.020
Abstract:
Sum frequency generation spectroscopy (SFG) has been widely used to study the interfacial chemistry of aqueous salt solutions of biological or environmental importance. Most of the SFG data analysis used the same bulk refractive index for different salt concentrations despite of the variations of the refractive indices. Here we systematically investigate the influence of the refractive index on the SFG intensities at various experimental conditions. It is discovered that the SFG intensities are the most sensitive to the refractive index at solid/liquid interfaces nearby the total internal reflection geometries. At air/liquid interfaces, the effect of the refractive indices is also nonegligible. Consequently some important SFG results, such as the response of water structures to the ionic strength at the SiO2/aqueous interfaces, are necessary to be reevaluated. These conclusions on the effect of the small variations of the refractive index are generally useful for the common practice of SFG data analysis.
Sum frequency generation spectroscopy (SFG) has been widely used to study the interfacial chemistry of aqueous salt solutions of biological or environmental importance. Most of the SFG data analysis used the same bulk refractive index for different salt concentrations despite of the variations of the refractive indices. Here we systematically investigate the influence of the refractive index on the SFG intensities at various experimental conditions. It is discovered that the SFG intensities are the most sensitive to the refractive index at solid/liquid interfaces nearby the total internal reflection geometries. At air/liquid interfaces, the effect of the refractive indices is also nonegligible. Consequently some important SFG results, such as the response of water structures to the ionic strength at the SiO2/aqueous interfaces, are necessary to be reevaluated. These conclusions on the effect of the small variations of the refractive index are generally useful for the common practice of SFG data analysis.
