ENZYME AND MICROBIAL TECHNOLOGY
·
2019
·
IF 3.553
Xuejia Shi,Jin Xu,Changning Lu,Zhenzhong Wang,Wei Xiao,Linguo Zhao
The magnetic particle Fe 3 O 4 -SiO 2 -NH 2 -Cellu-ZIF8 (FSNCZ8) was used to immobilize the high-temperature resistant GH3 β-glucosidase (Tpebgl3) from the Thermomotoga petrophila DSM 13995. The Tpebgl3 has great potential in the catalytic conversion of pharmaceutically active components. The magnetic carrier (FSNCZ8) which provided stronger adsorption capacity, magnetic and high-temperature stability than the previously discussed Fe 3 O 4 -NH 2 -Cellu-ZIF8 without tetraethyl silicate coated. The properties of FSNCZ8-Tpebgl3 (FSNCZ8-T) were as follows: The optimal temperature and pH were 90 °C and 5.5, respectively; the highest activity of FSNCZ8-T approached 2672 U/g; Fe 2+ enabled immobilized enzyme to increase its relative activity to 194%. The main characteristics of FSNCZ8-T, including thermal stability, pH stability, and glucose tolerance, were greatly enhanced by adding Fe 2+ , which was also superior to free enzymes; moreover, the residual activity of FSNCZ8-T was 74% of the initial activity at the end of 10 repeated cycles.
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高影响因子
RESEARCH ON CHEMICAL INTERMEDIATES
·
2018
·Vol. 44
·期 5
·2983-2998
·
IF 1.674
He Changhua,Zhou Qigang,Duan Zhengyang,Xu Xiaojun,Wang Fuhai,Li Hui
A new multifunctional β-cyclodextrin-sodium xanthogenate (β-CDX) was successfully synthesized by a one-step process and applied to remove Pb(II) from aqueous solutions. The characteristics and chelation mechanisms of β-CDX were investigated by Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy, and the influences of various operating parameters such as pH (lime dosage), the order of the additions, β-CDX dosage, and the initial concentration of Pb(II) on the removal capacity of β-CDX and the characteristics of the products were systematically evaluated. The results demonstrated that the optimal removal effect for Pb(II) was achieved when β-CDX was used rather than using lime alone. In addition, it was more effective to add β-CDX to the working solutions prior to adding the lime than adding β-CDX after the lime. The use of 0.05 g/L of β-CDX was effective for the removal of Pb(II) according to the residual concentration when the initial concentration was 100 mg/L at different pH values. The maximum removal rate of the Pb(II) ions was 98% for all initial concentrations and the products were larger (size = 137.9 μm) and looser ( D f = 1.73) at an optimum pH range from 9 to 12. The characterization results confirmed that the RC(S)SNa in the β-CDX was the main contributor to the chelation of the Pb(II). These properties of β-CDX make it a promising compound for the treatment of wastewater contaminated by hazardous metal ions.
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RESEARCH ON CHEMICAL INTERMEDIATES
·
2018
·Vol. 44
·期 4
·2889-2911
·
IF 1.674
Qi Caixia,Liu Huijun,Deng Shanxia,Yang AoHui,Li Zhendong
The inclusion complex (sulfated-β-CD@NAA) of sulfated β-cyclodextrin and α-naphthylacetic acid was synthesized for adsorption of low concentrations of thorium from aqueous solutions. The structure and property of sulfated-β-CD@NAA were characterized by Fourier transform infrared spectroscopy, thermogravimetric, X-ray diffraction, proton nuclear magnetic resonance, specific surface area measurement and scanning electron microscopy. The characterization analysis confirmed the formation of new solid phase. The results indicated that α-naphthylacetic acid embedded into the cavity of sulfated β-cyclodextrin partly from the secondary face and the thermal stability of inclusion complex was significantly increased. The experiments were designed by Box–Behnken design combined with response surface methodology. The adsorption parameters of pH value, contact time, initial concentration were used as the independent variables and their effects were investigated on the Th(IV) adsorption capacity. Second-order polynomial regression models were derived and analysis of variance was utilized to judge the adequacy of the chosen models. The maximum Th(IV) adsorption capacity (12.75 mg g −1 ) was achieved under the following conditions: pH value 2.5, contact time 35 min, initial concentration 30 mg L −1 . Prediction of models was in good agreement with experimental results. The experimental adsorption kinetic data followed a pseudo-second-order equation with the correlation of 0.9996, indicating the chemical adsorption. The obtained equilibrium isotherm data were fitted well with Langmuir model in the concentration range considered. The thermodynamic parameters ( ∆H 0 < 0, ∆S 0 < 0, ∆G 0 < 0) indicated that the adsorption process was exothermic and spontaneous. Regeneration of Th(IV)-loaded sulfated-β-CD@NAA with 0.1 M HNO 3 solution, and the regenerated sulfated-β-CD@NAA can be reused for adsorption of Th(IV).
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Journal of Materials Chemistry A
·
2018
·Vol. 6
·期 14
·6054-6064
·
IF 9.931
Lechen Diao,Jian Qin,Naiqin Zhao,Chunsheng Shi,Enzuo Liu,Fang He,Liying Ma,Jiajun Li,Chunnian He
Hollow β-Mo2C/N-doped carbon composite nanospheres constructed by mesoporous ultrathin carbon nanosheets anchored with ultrasmall β-Mo2C nanoparticles were synthesized through a facile green process. Nanobubbles generated by ethanol–water exchange were utilized as templates for the core, while the precipitates in the solution were directly adopted as the emulsion stabilizer and the shell. Upon the self-polymerization of dopamine, a robust shell consisting of the Mo–polydopamine complex was formed. The size of the as-obtained hollow Mo–polydopamine nanospheres can be tuned by varying the type of gas, which is proportional to the supersaturation of gas. These precursors of hollow Mo–polydopamine nanospheres were then converted into hollow β-Mo2C/N-doped carbon composite nanospheres by high-temperature carbonization treatment. The N-doped carbon matrix can act as an electron conductor and facilitate the prevention of the migration and aggregation of the Mo2C nanoparticles, while the ultrafine Mo2C nanoparticles can achieve maximum material utilization for hydrogen evolution electrocatalysis. In addition, the mesoporous 2D nanosheets combined with their constructed 3D hollow structures can expose numerous active catalytic sites while enabling free diffusion of the electrolyte and mass transfer. As a result, the hollow β-Mo2C/N-doped carbon composite nanospheres exhibit low overpotentials and robust cycling stability in both acidic and alkaline electrolytes.
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Journal of Materials Chemistry C
·
2018
·Vol. 6
·期 20
·5453-5461
·
IF 5.976
Shaohua Fan,Guojun Gao,Shiyu Sun,Sijun Fan,Hongtao Sun,Lili Hu
Absolute quantum efficiency (QE) of up-conversion (UC) materials is still limited to ∼3%, which strongly limits their applications in many areas. Herein, we report highly efficient UC β-NaYF4:Yb3+,Er3+ micro-cylinders prepared via a newly developed Li+/Na+ ion exchange method (IEM) with absolute QE as high as ∼4.0%. A small amount of Li+ is interstitially incorporated in β-NaYF4:Yb3+,Er3+, which not only maintains well the micro-cylindrical morphology but also enhances the emission intensity by ∼40%, doubles absolute UCQE (∼3.0% under a fixed excitation power density of 15 W cm−2), and prolongs the lifetime. The UC excitation profile is composed of a sharp peak at 976 nm and a weak shoulder at 935 nm. The absolute UCQE of Li+/Na+ IEM β-NaYF4:Yb3+,Er3+ is systemically studied over a wide excitation power density of 0.4–100 W cm−2, and we obtained impressively high UCQE of 4.0% under 60 W cm−2 power density, which is among the highest values in the literature. The application of two green UC emissions of Li+/Na+ IEM β-NaYF4:Yb3+,Er3+ in ratiometric thermometers is successfully demonstrated. The high relative temperature sensitivity (SR) of 1113/T2 and excellent repeatability as indicated by three heating–cooling cycles (293–753 K) suggest their promising application as a temperature sensor.
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JOURNAL OF MATERIALS SCIENCE
·
2018
·Vol. 54
·期 2
·1677-1691
·
IF 2.993
Yang Ning,Wang Yue,Zhang Qingsong,Chen Li,Zhao Yiping
Despite their considerable potential, using in situ injectable hydrogels for drug delivery has some associated drawbacks. The ratio of precursor to reaction required for gelation is a relatively fine balance, and low strength makes the gel prone to plastic deformation. To improve gel strength, poly (thiolated chitosan- co -alkylated β-cyclodextrin) [poly (CS-SH- co -Alkynyl-β-CD)] hydrogels with high cross-linking density were first obtained by click chemistry. Chitosan and cyclodextrins are derived from natural polymers and can be modified with mercapto and alkynyl groups, respectively, to achieve gels with high cross-linking density. The physical properties of the gels were optimized by adjusting the mass ratio of thiolated chitosan and alkylated β-cyclodextrins. Experiments revealed that the in situ hydrogels exhibit good mechanical properties. Furthermore, the specific binding and controlled release of a model drug, bendamustine hydrochloride, were studied using in situ gels as carriers. The in situ hydrogel also exhibited excellent degradation. In situ mutual cross-linking poly (CS-SH- co -Alkynyl-β-CD) hydrogels are therefore an efficient drug delivery method requiring minimal invasive surgery, and have attractive application prospects in the treatment of solid tumors.
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Journal of CO2 Utilization
·
2018
·
IF 5.503
Dandan Song,Di Li,Xuan Xiao,Chen Cheng,Somboon Chaemchuen,Ye Yuan,Francis Verpoort
A green and recyclable catalytic system based on AgBr and an ionic liquid (IL) was developed for the three-component coupling reaction of propargylic alcohols, secondary amines and carbon dioxide (CO 2 ). A series of target carbamates, especially those generated from challenging substrates, could be obtained smoothly at atmospheric CO 2 pressure in a straightforward one-pot process. Moreover, the catalyst loading reached the lowermost level ever reported. Particularly, this catalytic system exhibited robust constancy and could be reused at least 5 times with retention of high catalytic activity. It is worth noting that this is the first catalytic system which could be recycled successfully for this reaction.
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JOURNAL OF SEPARATION SCIENCE
·
2019
·Vol. 42
·期 16
·2734-2742
·
IF 2.516
Wenyu Sun,Chaoyue Wang,Yang Jin,Xiang Wang,Shanshan Zhao,Meng Luo,Jizhong Yan,Shengqiang Tong
Four stereoisomeric components were produced during the synthesis of the antidepressant drug ( 1S, 4S )-sertraline hydrochloride due to the two chiral carbon centers in its chemical structure, including ( 1S, 4S ), ( 1R, 4R ), ( 1S, 4R ), and ( 1R, 4S )-isomer. Stereoselective separation of the target isomer ( 1S, 4S )-sertraline from the medicinal reaction mixtures by countercurrent chromatography using hydroxypropyl-β-cyclodextrin as the stereoselective selector was investigated. A biphasic solvent system composed of n -hexane/0.20 mol/L phosphate buffer solution with pH 7.6 containing 0.10 mol/L of hydroxypropyl-β-cyclodextrin (1:1, v/v) was selected for separation of cis -sertraline and trans -sertraline using reverse phase elution mode and ( 1S, 4S )-sertraline was separated with ( 1R, 4R )-sertraline using recycling elution mode. A fabricated in-house analytical countercurrent chromatographic apparatus was used for optimization of the separation conditions. Stationary phase retention and peak resolution were investigated for separation of cis -sertraline and trans -sertraline by the analytical apparatus.
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高影响因子
POLYMER TESTING
·
2017
·
IF 2.464
Jing Cao,Na Wen,Yuying Zheng
Ca-montmorillonite (Ca-MMT) was first modified with different amount of two different kinds of surfactants to obtain organo-montmorillonites (OMMTs) directly via ion exchange between Ca 2+ and alkyl ammonium cations. Then remained Ca 2+ in OMMTs was reacted with pimelic acid (HA) to obtain CaHA-OMMTs. PP/CaHA-OMMT composites were prepared. Results of FT-IR demonstrate the existence of long-chain alkyl in OMMTs, and CaHA in CaHA-OMMTs. The reaction between HA and OMMT could lead to an increase in d-spacing value of clay. CaHA-OMMTs with high CaHA contents and obviously increased d-spacing values were obtained. Results of WAXD and TEM show exfoliated clay platelets in PP/CaHA-OMMT composites. The obviously increased T c , and the high β-phase content in PP/CaHA-OMMT composites demonstrate the high β-nucleation efficiency of CaHA-OMMTs. Composites with higher content of β-phase epitaxial crystallized on exfoliated clay platelets display largely improved impact strength .
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高影响因子
Frontiers of Materials Science
·
2017
·Vol. 11
·期 3
·223-232
·
IF 1.471
Wei Lulu,Lu Beibei,Li Lei,Wu Jianning,Liu Zhiyong,Guo Xuhong
A novel β-cyclodextrin-poly(2-(2-methoxyethoxy)ethyl methacrylate)- co -poly(ethylene glycol) methacrylate (abbreviated as: β-CD-(P(MEO 2 MA- co -PEGMA)) 21 ) was prepared by using the one-step strategy, and then the star-shaped copolymers were used in the atom transfer radical polymerization (ATRP). The structure of star-shaped β-CD-(P(MEO 2 MA- co -PEGMA)) 21 copolymers were studied by FTIR, 1 H NMR and gel permeation chromatography (GPC). The star-shaped copolymers could self-assembled into micelles in aqueous solution owing to the outer amphiphilic β-CD as a core and the hydrophilic P(MEO 2 MA- co -PEGMA) segments as a shell. These thermo-responsive starshaped copolymers micelles exhibited lower critical solution temperature (LCST) in water, which could be finely tuned by changing the feed ratio of MEO 2 MA to PEGMA. The LCST of star-shaped β-CD-(P(MEO 2 MA- co -PEGMA)) 21 copolymer micelles were increased from 35°C to 58°C with the increasing content of PEGMA. The results were investigated by DLS and TEM. When the temperature was higher than corresponding LCSTs, the micelles started to associate and form spherical nanoparticles. Therefore, β-CD-(P(MEO 2 MA- co -PEGMA)) 21 star-shaped copolymer micelles could be potentially applied in nano-carrier, nano-reactor, smart materials and biomedical fields.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2017
·
IF 5.401
Yufeng Sun,Tingting Wei,Mingdi Jiang,Longhua Xu,Zhixiang Xu
A simple and sensitive three-dimensional voltammetric sensor was constructed for the determination of chloramphenicol (CAP). First, ordered mesoporous carbon was introduced onto a glassy carbon electrode to improve the electron transport performance, and then a polydopamine layer was formed on the surface to enhance the hydrophilicity and provide a negative charge to attract positively charged CAP. Finally, the electrode surface was modified through electrochemical polymerization with β-cyclodextrin, which contains abundant hydroxygroups to provide more hydrogen-bonding sites for CAP binding. The developed sensor was investigated with square wave voltammetry and cyclic voltammetry, and exhibited a rapid current response and high selectivity for CAP. Under optimal conditions, the method offered a wide current response for CAP from 5.0 × 10 −7 to 5.0 × 10 −4 mol L −1 and the limit of detection was 2.0 × 10 −7 mol L −1 . Milk powder and bee pollen samples spiked with CAP were extracted and then determined using the β-CD/ [email protected] /GCE sensor with satisfactory recoveries of 80.0%-101.6%. The method was also used to determine CAP residues in real milk and honey samples, and the results correlated well with those obtained using high-performance liquid chromatography.
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SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
·
2024
·
IF 4.3
Ruiqi Huang,Yingfeng Qin,Yanqin Huang,Zengqiong Huang,Gao-Jie Ye
6-mercaptopurine (6-MP) is widely used in the treatment of many diseases, but exhibits some serious side effects due to its toxicity. Therefore, it is important and imperative to effectively control and monitoring concentration of 6-MP. Herein, we designed a smartphone-assisted colorimetric sensing platform for 6-MP detection, based on an excellent β-cyclodextrin modified MnO 2 nanosheets (β-CD@MnO 2 NNS) mediated oxidase-like activity. β-CD@MnO 2 NNS can directly oxidizes 3,3′,5,5′-tetramethylbenzidine (TMB) into oxidized TMB with color changes, yielding more than 3-fold higher oxidase-like catalytic activity compared with individual MnO 2 NNS. After adding 6-MP, β-CD@MnO 2 NNS can be reduced to Mn 2+ and lose their oxidase-like properties, resulting in a color and absorbance change for sensitive and selectivity detection of 6-MP. Meanwhile, the smartphone-based color recognition application can intuitively and simply measure the concentration of 6-MP. The limits of detection UV–vis instrument and smartphone were 0.35 μM and 0.86 μM, respectively. This method has also been successfully applied to the detection of real samples. Finally, this study provides a new promising platform for detection of 6-MP and is expected to be used in application of pharmaceutical analysis and biomedicine.
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