JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
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2017
·Vol. 84
·期 2
·290-296
·
IF 1.575
Li Jie,Zhang Jia,Chen Lianxi,Wang Pengpeng,Wang Yu
Abstract In this study, highly monodisperse cyanoethyl-/cyanopropyl-functionalized silica micro/nanospheres (CN-E-SiO 2 /CN-P-SiO 2 ) have first been synthesized via one-pot sol–gel reaction at room temperature in the microemulsion system. Effects of the surfactant concentrations and the reaction time on the formation of CN-E-SiO 2 /CN-P-SiO 2 have been discussed. Furthermore, bifunctional core–shell structures prepared using CN-E-SiO 2 and CN-P-SiO 2 as core and ureidopropyl-functionalized silica spheres (UD-SiO 2 ) as shell, denoted as CN-E-SiO 2 @UD-SiO 2 and CN-P-SiO 2 @UD-SiO 2 , have also been etched separately in alkaline conditions. Compared with the original CN-E-SiO 2 and CN-P-SiO 2 , transmission electron microscopy images showed that the diameter of CN-E-SiO 2 @UD-SiO 2 and CN-P-SiO 2 @UD-SiO 2 core–shell structures was all reduced during etching in alkaline condition, finally resulting in a hollow structure with a similar sphere size. In addition, for the sake of comparison, pure silica as core and UD-SiO 2 as shell, denoted as SiO 2 @UD-SiO 2 core–shell structure, has also been prepared. However, transmission electron microscopy image indicated that the size and shape of SiO 2 @UD-SiO 2 was almost unchanged in the whole etching process. It can be proved that selective etching of bifunctional core–shell organosilica is an optimal strategy for preparation of hollow materials. Graphical Abstract
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高影响因子
Journal of the Iranian Chemical Society
·
2017
·Vol. 14
·期 9
·1957-1970
·
IF 1.407
Xiao Qi,Lu Shuangyan,Huang Chusheng,Su Wei,Zhou Shuyu,Sheng Jiarong,Huang Shan
An electrochemical chiral sensing platform based on amino-functionalized graphene quantum dots/β-cyclodextrin modified glassy carbon electrode (NH 2 -GQDs/β-CD/GCE) was developed for enantioselective detection of tryptophan (Trp) isomers. NH 2 -GQDs/β-CD/GCE showed high electrocatalytic activity and good analytical behavior toward the oxidation of Trp isomers. The oxidation peak potentials and oxidation peak currents of Trp isomers at NH 2 -GQDs/β-CD/GCE surface were observed by differential pulse voltammetry. NH 2 -GQDs/β-CD nanocomposite exhibited different binding ability for two Trp isomers and selectively bonded with d -Trp, resulting in the higher oxidation peak current of d -Trp at NH 2 -GQDs/β-CD/GCE surface. Trp isomers exhibited different oxidation peak potentials at NH 2 -GQDs/β-CD/GCE surface, and the peak potential separation between l -Trp and d -Trp was around 0.022 V, which was used for the enantioselective detection of Trp isomers. Under the optimum experimental conditions, the oxidation peak currents were linearly dependent on the concentrations of Trp isomers. The linear ranges of l -Trp and d -Trp were all from 1.0 to 30.0 μM with correlation coefficients of 0.9886 and 0.9800, respectively. The detection limits of l -Trp and d -Trp were 0.65 and 0.12 μM (3 σ / K ), respectively. Such NH 2 -GQDs/β-CD/GCE displayed high anti-interference against some physiological substances, good reproducibility and excellent long-term stability toward Trp isomers detection in biomedical applications.
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高影响因子
MICROCHIMICA ACTA
·
2016
·Vol. 183
·期 6
·1909-1916
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IF 4.831
Dai Shaoliang,Wu Shijia,Duan Nuo,Wang Zhouping
The authors describe a turn-on luminescence resonance energy transfer (LRET) method for the detection of the mycotoxin Ochratoxin A (OTA). It utilizes upconversion nanoparticles (UCNPs) of the type NaYF 4 : Yb, Er as the energy donor and gold nanorods (Au NRs) as the acceptor. Biotin-labeled OTA aptamers were bound to the surface of the avidin-functionalized UCNPs. The AuNRs, in turn, were modified with thiolated OTA aptamer cDNA via thiol chemistry. The emission band of the UCNPs under 980-nm laser excitation has a maximum peaking at 657 nm and overlaps the absorption band of the AuNRs which peaks at 660 nm. Quenching of luminescence occurs because the hybridization actions shorten the distance between UCNPs and AuNRs. If, however, OTA is added, the two kinds of particles separate again because of the high affinity between OTA and the OTA aptamer. As a result, luminescence is recovered. The calibration plot is linear in the 0.05 to 100 ng mL −1 OTA concentration range, and the limit of detection is 27 pg mL −1 . The method was successfully applied to the determination of OTA in beer.
The luminescence of aptamer-modified upconversion nanoparticles (avidin-UCNPs) is quenched by cDNA-modified gold nanorods (AuNRs) due to hybridization. In the presence of Ochratoxin A (OTA), however, the luminescence of the UCNPs recovers due to competitive binding of aptamer to OTA.
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高影响因子
KOREAN JOURNAL OF CHEMICAL ENGINEERING
·
2016
·Vol. 33
·期 5
·1692-1697
·
IF 1.408
Yue Hongya,Liu Zhigang
Density and surface tension have been measured for mixtures of biodiesel+ n -butanol, biodiesel+diesel, and diesel+ n -butanol over the entire concentration range at 283.15 K and 293.15 K and atmospheric pressure, with the combined expanded uncertainties of 1.32 kg·m −3 and 1%, receptively. Densities were determined by a single-sinker densimeter; surface tensions were measured using the surface laser light scattering method. The experimental data showed that densities and surface tensions decreased as temperature increased. The excess surface tensions and excess densities were all negative, and further fitted to the Redlich-Kister equation.
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高影响因子
Science Bulletin
·
2016
·
IF 0
Hui-Zhen Cui,Ying-Qiu Gu,Xin-Xin He,Shuai Wei,Zhao Jin,Chun-Jiang Jia,Qi-Sheng Song
Iron-based composite nanostructures with ceria or titania as shell coating on naked iron spheres were successfully synthesized and used to catalyze ammonia decomposition . The structure and texture of fresh and used catalysts were characterized by transmission electron microscopy , X-ray diffraction, in situ X-ray diffraction, temperature-programmed reduction by hydrogen, and N 2 adsorption–desorption. For ammonia decomposition , the iron-based composite catalyst coated with cerium and titanium showed excellent catalytic activity compared with naked iron sphere catalyst, with the former yielding nearly 100% ammonia conversions at 650 °C and showing high stability in the catalysis test (for 60 h) at 600 °C with a space velocity of 24 , 000 cm 3 g cat − 1 h − 1 . These results showed that adding cerium and titanium played a key role in improving catalytic activity for ammonia decomposition and enabling high thermal stability .
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COLLOID AND POLYMER SCIENCE
·
2016
·Vol. 295
·期 1
·205-213
·
IF 1.89
Tao Huiwen,Zhang Xueqin,Sun Ying,Yang Hong,Lin Baoping
To clarify the influence of molecular weight of siloxane macromonomer on phase separation morphology, oxygen permeability, and mechanical properties, silicone hydrogels were prepared by copolymerizing mixtures of methacrylate-terminated siloxane macromonomer (MTSM), silicon-containing monomers tris(trimethylsiloxy)-3-methacryloxpropylsilane, and three hydrophilic monomers N , N -dimethylacrylamide, N -vinylpyrrolidone, and hydroxypropyl methacrylate. The number of Si–O–Si repeating units was equal in every silicone hydrogel while the molecular weight of MTSM ranged from 1000 to 10000 g/mol. The oxygen permeability coefficient (Dk), equilibrium water content (EWC), light transmittance, mechanical properties, and internal morphologies of obtained silicone hydrogels were characterized, and their relationships were discussed in detail. The results showed that the Dk value increased first and then decreased with the chain length of MTSM increasing. The EWC presented an increasing trend and the light transmittance decreased with the increase of MTSM chain length. The elongation increased while the modulus and the tensile strengths of the silicone hydrogels decreased along with the MTSM molecular weight increasing. The internal morphologies of the silicone hydrogels were observed by transmission electron microscope. The results indicated that the silicone hydrogels presented different phase separation structures depending on the molecular chain length of MTSM. The continuous silicone phase formed and made significant contributions to high Dk value as the molecular chain length of MTSM was moderate. Besides, a model was proposed to explain the effect mechanism of the MTSM chain length on the oxygen permeability and the EWC. This work provided a facile method to preparing the silicone hydrogel materials with desirable water absorption and high oxygen permeability by adjusting the molecular weight of macromonomers.
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MICROCHIMICA ACTA
·
2016
·Vol. 184
·期 3
·677-686
·
IF 4.831
Zhao Shuang,Zhang Jun,Li Zhengping,Zhang Peixin,Li Yunxiao,Liu Guohua,Wang Yong,Yue Zhao
Nanocomposites consisting of gold nanoclusters and graphene oxide (AuNC/GO) were prepared and investigated with respect to the design of new sensors for hydrogen peroxide (H 2 O 2 ). The AuNC/GO hybrid nanomaterials were deposited on a gold electrode by the layer-by-layer assembly method, where they showed enhanced photoelectrical and sensing properties. The presence of graphene oxide improves the photoinduced electron separation efficiency of the AuNCs, as well as the catalytic effect of AuNCs on the electroreduction of H 2 O 2 . Compared to an electrode modified with AuNCs only, the new electrodes display a more than ten-fold enhanced photocurrent at a working voltage of -500 mV (vs. Ag/AgCl), higher sensitivity for H 2 O 2 (25.76 nA⋅mM −1 ), lower LOD (2 μM) and extended linear range (from 30 μM to 5 mM). The sensors were applied to the determination of H 2 O 2 extracted from living human umbilical vein endothelial cells stimulated by angiotensin II.
Graphene oxide (GO) not only improves the photoinduced charge separation efficiency of fluorescent gold nanoclusters (AuNCs) based photoelectrochemical sensors, but also enhances the catalytic property of AuNCs on the detection of hydrogen peroxide (H 2 O 2 ).
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高影响因子
ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2016
·Vol. 409
·期 6
·1627-1633
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IF 3.125
Wang Yihong,Guo Qing,Wang Huafu,Qian Kun,Tian Liang,Yao Chen,Song Wei,Shu Weixia,Chen Ping,Qi Jinxu
Quaternized chitosan is a cationic biopolymer with good antibacterial activity, biocompatibility, and biodegradability, and it has been widely applied in many fields. We have developed a convenient method to evaluate the antibacterial activity of hydroxypropyltrimethylammonium chloride chitosan (HACC) with a nonionic surfactant poloxamer in aqueous solution by monitoring the change of the oxidation peak current in cyclic voltammetry. Increasing values of the oxidation peak current were positively correlated with the antibacterial activity of HACC–poloxamer solutions. Optical microscope images, the zeta potential, and fluorescence spectroscopy showed that the aggregation state of HACC–poloxamer was related to the ratio of the two polymers and also to the antibacterial activity and oxidation peak current. At an HACC-to-poloxamer ratio of 1:0.75, the maximum surface charge density and the smooth edge of HACC–poloxamer aggregates can accelerate diffusion in aqueous solution. It is expected that this convenient method can be applied for a quick evaluation of the antibacterial activity of cationic biopolymers in aqueous solution.
The cyclic voltammograms of MB in HACC/poloxamer solution, and the antibacterial efficiency against S. aureus after incubated with HACC ( a ) and 1/0.75 of HACC/poloxamer ( b )
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PubMed
高影响因子
MICROCHIMICA ACTA
·
2016
·Vol. 184
·期 2
·445-451
·
IF 4.831
Wang Cong,Sun Junyong,Mei Han,Gao Feng
The authors describe a fluorescent probe for sulfide that is based on carboxy-functionalized semiconducting polymer dots (P-dots). The dots were prepared from carboxy-functionalized poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-benzo-2,1′-3-thiadiazole)] (referred to as COOH-PFBT) via co-precipitation. The P-dots aggregate on addition of Cu(II) ions and their green fluorescence (with excitation/emission peaks at 455/540 nm) is then quenched. Fluorescence is restored on addition of sulfide to the aggregates due to the formation of CuS. This quenching-recovery (“off-on”) mechanism forms the basis for a new sulfide detection scheme. Fluorescence increases linearly in the 1.25 to 75.0 μM sulfide concentration range, with a 0.45 μM detection limit. Good selectivity over other anions is demonstrated. The method shows recoveries ranging between 98.6% and 105.7% when applied to the determination of sulfide in spiked real water samples.
Schematic of a fluorescent off-on sensor for (hydrogen) sulfide based on the use of semiconducting polymer dots (PFBT-COOH) whose fluorescene is quenched by Cu(II) ion but restored on addition of (hydrogen) sulfide.
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高影响因子
CHEMICAL PAPERS
·
2016
·Vol. 71
·期 5
·913-920
·
IF 1.326
Li Yancai,Zhong Yanmei,Huang Jixian
A lanthanum metal–organic framework, [La(BTC)(H 2 O)(DMF)] (H 3 BTC = 1, 3, 5-benzenetricarboxylic acid), was synthesized under mild hydrothermal conditions. The synthesized [La(BTC)(H 2 O)(DMF)] was characterized by scanning electron microscopy in combination with energy dispersive X-ray spectroscopy (SEM/EDS), transmission electron microscopy (TEM), X-ray diffraction (XRD), and fourier transform infrared spectroscopy (FT-IR). Its electrochemical properties and electrocatalytic activity towards H 2 O 2 reduction in acidic media were studied by cyclic voltammetry (CV) and amperometric current–time response. The [La(BTC)(H 2 O)(DMF)] modified electrode shows good electrochemical behavior and performs well electrocatalytic activity towards hydrogen peroxide (H 2 O 2 ) reduction at ca. −0.7 V. The modified electrode displays a linear range from 5 μM to 2.67 mM and a limit of detection of 0.73 μM to H 2 O 2 . The [La(BTC)(H 2 O)(DMF)] modified electrode also possesses good selectivity and stability. Thus, [La(BTC)(H 2 O)(DMF)] will be a promising material for non-enzymatic H 2 O 2 sensor.
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ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY
·
2016
·Vol. 72
·期 1
·153-165
·
IF 2.039
Ma Taowu,Wang Meng,Gong Shuangjiao,Tian Bin
The environmental factors are expected to affect the ecotoxicity of heavy metals in the presence of engineered nanoparticles (NPs) in aquatic ecosystems. However, in sediment scenario, little is known regarding their impacts on the ecotoxicity of co-exposure of sediment-associated heavy metals and NPs. This study evaluated the impacts of different levels of organic matter (OM) (4.8–11.6%) and pH (6–9) on the ecotoxicological effects of co-exposure of sediment-associated titanium dioxide nanoparticles (TiO 2 -NPs) and cadmium (Cd) to a freshwater gastropod Bellamya aeruginosa . The burdens of Ti and Cd and biomarkers of DNA damage, Na + /K + -ATPase, lipid peroxidation (LPO), and protein carbonylation (PC) in the hepatopancreas were determined following 21 days of exposure. At background level of OM (4.8%) in sediments, TiO 2 -NPs significantly promoted Cd accumulation in low-Cd treatments (5 mg/kg) but did not promote Cd accumulation in high-Cd treatments (25 mg/kg). At the relatively higher OM levels (7.1 and 11.6%), TiO 2 -NPs significantly enhanced Cd accumulation and toxicity as evidenced by aggravated DNA damage, decreased Na + /K + -ATPase activities, and increased LPO and PC levels. Moreover, Cd burdens in both low-Cd and high-Cd treatment were positively correlated with corresponding Ti burdens, indicating TiO 2 -NPs partially acted as carrier of Cd. At all pH levels, in low-Cd treatments, TiO 2 -NPs did not affect Cd accumulation, LPO, and PC levels but significantly enhanced DNA damage and slightly facilitated the inhibition of Na + /K + -ATPase activities. In high-Cd treatments, only at pH 9, TiO 2 -NPs significantly enhanced Cd accumulation and toxicity. Our results implied that interaction between TiO 2 -NPs and OM or pH significantly affected the accumulation and toxicity of Cd in B. aeruginosa , but the underlying mechanisms need further investigation. Additionally, it should be noted that the potential ecological risk of co-exposure of NPs and coexisting pollutants might be closely species-specific and related to environmental media.
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PubMed
高影响因子
POLYMER BULLETIN
·
2016
·Vol. 74
·期 4
·911-930
·
IF 1.371
Yang Jin,Lu Shaorong,Pan Lulu,Luo Qiyun,Song Laifu,Wu Lingyan,Yu Jinhong
A new green compatibilizer named epoxidized soybean oil grafted poly(12-hydroxy stearate) (ESO- g -PHS) was successfully synthesized using 12-hydroxy stearic acid and epoxidized soybean oil (ESO). The chemical structure of ESO- g -PHS was investigated through Fourier transformed infrared spectroscopy, thermogravimetric analysis, and gel permeation chromatography. ESO- g -PHS was used as a compatibilizer to enhance the interfacial compatibility between polypropylene (PP) and microcrystalline cellulose fibers (MCF). The results showed that the impact strength and tensile strength were 33.55 and 27.57 MPa when the content loading of MCF reached 10 wt% and ESO- g -PHS was 4 wt%, which enhanced by 75.4 and 30.04 %, respectively, compared to that of composites without ESO- g -PHS. In addition, the SEM images of the fracture surfaces display that PP was highly bonded to MCF with ESO- g -PHS treated. In addition, the wide angle X-ray diffraction measurement revealed that the addition of ESO- g -PHS did not change the crystal structure of PP. Moreover, there was a slight improvement in thermal properties for PP composites with the addition of ESO- g -PHS.
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高影响因子
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