DALTON TRANSACTIONS
·
2019
·Vol. 48
·期 6
·2077-2085
·
IF 4.052
Jie He,Shanshan Sun,Zhao Zhou,Qipeng Yuan,Yanhui Liu,Hao Liang
A novel magnetic responsive Ni-based metal–organic framework material was developed to efficiently separate and immobilize thermal enzymes with high catalytic performance. Ni-based metal–organic framework nanorods (Fe3O4/Ni-BTC) with high magnetic responsiveness are prepared conveniently by a one-pot hydrothermal process. With the characterization, it was confirmed that Ni-based metal–organic framework nanocomposites were synthesized as nanorods mounted with magnetic Fe3O4 nanoparticles on the surface. Although Fe3O4/Ni-BTC showed a preference for histidine-tagged enhanced green fluorescent protein (His-eGFP), we found that a variety of forces played roles in enzyme immobilization, including affinity between Ni2+ and histidine tags, electrostatic attraction, hydrogen bonding and hydrophobic forces. After understanding the mechanism of the as-prepared nanocomposites, a new immobilization strategy for thermostable S-adenosylmethionine synthetase (SAMS) was further evaluated. As a result, SAMS from cell lysate achieved about 95% activity recovery in the biosynthesis of S-adenosylmethionine (SAM) under high temperature conditions (70 °C) with a simple mixing step. At the same time, the immobilized enzyme was more stable against temperature variation (by nearly 8-fold in an 80 °C water bath after 2 h) and extreme pH (by nearly 1.3-fold at pH 3) and exhibited excellent reusability after immobilization. This work indicates that magnetic responsive Ni-based nanorods are highly promising for thermostable enzyme immobilization with high efficiency and stability.
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高影响因子
NEW JOURNAL OF CHEMISTRY
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2019
·Vol. 43
·期 6
·2790-2796
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IF 3.069
Xiuxiu Zhao,Xin Lin,Jianhua Wang,Xuwei Chen
Nitrogen and sulfur co-doped graphene oxide nanosheets (N,S-GO) were prepared via a facile one-step solvent-free approach using citric acid as a precursor and cysteine as a dopant. First, the graphene nucleus was formed via intermolecular dehydration of citric acid; N and S were then incorporated into the graphene structure by attacking the margin of the graphene nucleus. Crosslinking among the graphene nucleus via intermolecular condensation led to the final N,S-GO. The latter exhibited favorable photoluminescence behaviors, such as a high fluorescent quantum yield of 56.0%, excellent photoluminescence stability within the pH range 5–12, and high tolerance to external ionic strength ≤1.0 mol L−1 NaCl. The fluorescence energy transfer between AgNPs and N,S-GO could induce efficient quenching of N,S-GO fluorescence, and the presence of biothiols in the system restored fluorescence effectively, so a fluorescence “off–on” procedure was developed for quantitative detection of biothiols. Under optimal conditions, the limit of detection for cysteine (Cys), homocysteine (Hcy) and glutathione (GSH) was 11.8, 4.9, and 7.3 nmol L−1, respectively. This sensing platform exhibited good selectivity toward biothiols in the presence of other amino acids. The practicability of this sensing platform was well demonstrated by determining biothiol content in human plasma samples, which revealed spiking recoveries of 97.10–101.50% with Cys.
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NEW JOURNAL OF CHEMISTRY
·
2018
·Vol. 42
·期 24
·20180-20189
·
IF 3.201
Jinping Song,Qi Ma,Sufang Zhang,Huijun Liu,Yong Guo,Feng Feng
In this paper, we reported a facile approach for the preparation of sulfur and nitrogen co-doped carbon nanoparticles (S,N-CNPs) with strong blue luminescence, which exhibited multiple applications including metal ion detection, logic gate fabrication and bioimaging. S,N-CNPs were synthesized by one-step hydrothermal treatment of formamidine sulfinic acid (FAS) and ethylene glycol. The as-synthesized S,N-CNPs possess a high quantum yield (Φ = 69.04%) and display excellent photostability and storage stability. By modulating the pH environment, S,N-CNPs were successfully applied as fluorescent probes for the detection of three kinds of heavy metal ions (Hg2+, Ag+ and Ni2+). The fabricated fluorescence sensors display ultrahigh sensitivity and a wider signal response range. More importantly, ethylenediamine (or ammonium thioglycolate and glycine) could efficiently release Hg2+ (or Ag+ and Ni2+) from the S,N-CNP surface, leading to the recovery of the fluorescence. According to this phenomenon, interesting implication (IMP) logic gates were constructed. In addition, the S,N-CNPs exhibited low toxicity, good biocompatibility and easy cellular uptake behavior. Consequently, the obtained S,N-CNPs will have potential applications in multiple fields of environmental monitoring, logic gate operation, and cell bioimaging.
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Polymer Chemistry
·
2018
·Vol. 9
·期 20
·2785-2796
·
IF 4.927
Lala Rukh Sidra,Guofei Chen,Nafeesa Mushtaq,Kai Ma,Beenish Bashir,Xingzhong Fang
Two asymmetric diamine monomers, incorporating both aryl ether and non-linear benzoxazole groups, namely 5-amino-2-(4-(4-aminophenoxy)phenyl)benzoxazole (p-BOODA) and 5-amino-2-(3-(4-aminophenoxy)phenyl)benzoxazole (m-BOODA), were designed and synthesized. Two novel series of poly(benzoxazole imide)s (PBOIs), PI-3(a–e) and PI-4(a–e), were prepared via thermal imidization of commercial tetracarboxylic dianhydrides with diamines p-BOODA and m-BOODA, respectively. The effects of chain isomerism on molecular packing and the physical properties of PBOIs are investigated. These PBOIs showed excellent mechanical properties with tensile strengths of 106–168 MPa, tensile moduli of 2.7–5.5 GPa and elongations at break of 4.4–9.3%; in addition, they exhibited good thermal stability (T5% = 488–570 °C) and high glass transition temperatures (Tgs) up to 333 °C. Moreover, BTDA (3,3′,4,4′-benzophenone tetracarboxylic dianhydride) derived PBOIs, PI-3b and PI-4b, showed crystalline transition in spite of bent groups and the asymmetric chain structure. The incorporation of the asymmetric benzoxazole structure with flexible ether connecting groups improved the solubility of the PBOI system. Furthermore, the controlled molecular weight (Mw) polymer PI-4e-PA derived from m-BOODA demonstrated excellent solution and melt processability with the lowest complex viscosity of 44 Pa s at 380 °C.
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Polymers
·
2018
·Vol. 10
·期 11
·1287
·
IF 2.935
Wenmeng Zhang,Shaoyun Chen,Dongyang Chen,Zhuoliang Ye
Sterically hindered (S)-1,1′-binaphthyl-2,2′-diol had been successfully copolymerized with 4,4′-sulfonyldiphenol and 4,4′-difluorobenzophenone to yield fibrous poly(arylene ether ketone)s (PAEKs) containing various amounts of binaphthyl unit, which was then selectively and efficiently sulfonated using ClSO3H to yield sulfonated poly(arylene ether ketone)s (SPAEKs) with ion exchange capacities (IECs) ranging from 1.40 to 1.89 mmol·g−1. The chemical structures of the polymers were confirmed by 2D1H–1H COSY NMR and FT-IR. The thermal properties, water uptake, swelling ratio, proton conductivity, oxidative stability and mechanical properties of SPAEKs were investigated in detail. It was found that the conjugated but non-coplanar structure of binaphthyl unit endorsed excellent solubility and film-forming capability to SPAEKs. The SPAEK-50 with an IEC of 1.89 mmol·g−1exhibited a proton conductivity of 102 mS·cm−1at 30 °C, much higher than that of the state-of-the-art Nafion N212 membrane and those of many previously reported aromatic analogs, which may be attributed to the likely large intrinsic free volume of SPAEKs created by the highly twisted chain structures and the desirable microscopic morphology. Along with the remarkable water affinity, thermal stabilities and mechanical properties, the SPAEKs were demonstrated to be promising proton exchange membrane (PEM) candidates for potential membrane separations.Keywords:proton exchange membranes;condensation polymerization;post-sulfonation;binaphthyl;film-forming capability
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JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY
·
2018
·
IF 2.891
Chunxi Zhao,Yang Jiao,Zhe Gao,Yaling Yang,Hong Li
Nitrogen and sulfur co-doped carbon dots (N, S co-doped CDs) were prepared from glutathione with a hydrothermal method and developed for temperature probe as well as fluorescent sensor of tetracycline. The as-prepared N, S co-doped CDs exhibited good optical properties, stability, water solubility and high fluorescence quantum yield(17.5%). The fluorescence intensity of the N, S co-doped CDs varied with temperature in the range of 10–70 °C. Moreover, based on the inner filter effect (IFE), the nanoparticle-based sensor displayed a wide linear range of 0.1–65 μM (R 2 = 0.9916) and provided an exciting detection limit of 0.04 μM (signal-to-noise ratio of 3) for quantifying tetracycline. More strikingly, the N, S co-doped CDs sensing system could commendably resist the interference from potential foreign substances, and achieved satisfactory recoveries, which indicated the excellent selectivity and sufficient accuracy of the sensor for real milk samples analyses. As a simple and effective optical nanosensor, the proposed N, S co-doped CDs hold admirable promise to broaden the applications in food analysis and others fields.
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JOURNAL OF MEMBRANE SCIENCE
·
2013
·
IF 4.093
Kunzhi Shen,Jinhui Pang,Sinan Feng,Yang Wang,Zhenhua Jiang
The poly(aryl ether ketone)s containing two quaternary ammonium groups on pendant phenyls are obtained via a bromination reaction following a quaternization process. Poly(aryl ether ketone)s with two methyl groups on pendant phenyls, which can be converted to bromomethyl groups by a radical reaction, are synthesized. Cationic quaternized poly(aryl ether ketone)s result from conversion of the bromomethyl groups to ionic moieties by quaternization with trimethylamine in the shape of clear, creasable films. The highest conductivity 0.0307 S cm −1 is achieved by the QMPAEK-75 membrane with ion exchange capacity of 1.35 meq. g −1 at 80 °C. Meanwhile, these anion exchange membranes also have good mechanical properties , very low methanol permeability, high thermal stability, chemical stability and dimensional stability, which play important roles in the preparation of direct methanol fuel cells.
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MATERIALS RESEARCH BULLETIN
·
2012
·
IF 2.105
Hongwei Wei,Hechun Jiang,Zhen Zheng,Quanqin Zhao,Qingyin Wu,Jinhua Zhan
A series of one-dimensional Cd x Zn (1− x ) S semiconductor alloys were prepared via a hydrothermal method with the assistance of ethylenediamine at 180 °C for 12 h. The products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, nitrogen adsorption/desorption and Fourier transform infrared techniques. With the value of x increased, the band gap of Cd x Zn (1− x ) S semiconductor alloys gradually decreased indicating that catalysts were exchanged to visible-light response. Photocatalytic reduction results showed that Cd 0.73 Zn 0.27 S exhibited the highest photocatalytic activity toward photo production of aniline via nitrobenzene reduction under visible irradiation respectively. The reaction mechanism was also discussed.
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ENERGY & FUELS
·
2015
·
IF 2.79
Fernando T. Reyes,Malcolm A. Kelland,Li Sun,Jian Dong
Novel citric-acid-based polyamides were synthesized by polycondensation reactions using tributyl citrate (TBC) and ethylene diamine (EDA), producing hyperbranched poly(ethylene citramide)s with NH2 termini, which were functionalized with isopropyl, n-butyl, and cyclohexyl groups via the urea group. Characterization was carried out by 1H and 13C nuclear magnetic resonance (NMR) spectroscopic techniques. Molecular weights in this polymer family varied from 3000 to 10 000 Da. The activity of this polymer family as gas hydrate kinetic inhibitors (KHIs) was evaluated for the first time. Constant cooling (1 °C/h) experiments were carried out in high-pressure steel rocking cells using a synthetic natural gas that preferentially forms structure II gas hydrates. The best KHI performance was given by poly(ethylene citramide) CONHCyHe with pendant N-cyclohexyl groups (Mn = 5.65 × 103, and Mw = 1.14 × 104). A structure–activity relationship (SAR) analysis of the KHI test results supports the hypothesis that increasing the size of the lipophilic groups increases the KHI performance as long as water solubility is maintained through hydrogen bonding via the amide and/or urea functional groups.
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HIGH PERFORMANCE POLYMERS
·
2015
·
IF 1.286
Qiuxiang Wu,Zhizhou Yang,Jinshui Yao,Donghong Yu
Five new optically active poly(amide–imide)s (PAIs) (PAI3a–PAI3e) were synthesized through the direct polycondensation reaction between chiral N,N′-(pyromellitoyl)-bis-l-amino acids and 4,4′-diaminodiphenyl ether. The resulted polymers were fully characterized by means of Fourier transform infrared (FTIR) and proton nuclear magnetic resonance spectroscopy, elemental analysis, inherent viscosity measurement, solubility tests, specific rotation, and thermogravimetric analysis (TGA). The biodegradation studies of the PAIs were performed in soil and in phosphate buffer solution. The surface morphology and hydrophobicity of the biodegraded PAI films were investigated. FTIR spectra showed structural changes on PAI powders being treated in phosphate buffer solution. The TGA data showed that the thermal stability of PAI powders decreased with the degradation time. The collected degradation products were soluble in water and had absorption in ultraviolet and visible light region. Possible biodegradation mechanism of amino acid-based PAIs was explored.
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CHINESE JOURNAL OF POLYMER SCIENCE
·
2015
·Vol. 33
·期 11
·1491-1502
·
IF 1.835
Fang Li-feng,Wang Na-chuan,Zhou Ming-yong,Zhu Bao-ku,Zhu Li-ping,John Angelin Ebanezar
To functionalize poly(vinyl chloride) (PVC) for various applications, monomers containing tertiary amine group are incorporated into PVC via atom transfer radical polymerization (ATRP) initiated by the labile chlorines in their backbones. The kinetics of synthesis was carefully investigated, and it is proven that the grafting polymerization process can be effectively controlled by regulating the reaction time. The membranes are fabricated using PVC and copolymers by non-solvent induced phase separation (NIPS) process. The hydrophilicity and pore structure of copolymer membranes were enhanced as well, these membranes are endowed with positive charge. When PDMA% ( i.e. , the PDMA weight percentage in copolymer) is 31.1%, the flux and Victoria blue B rejection are 26.0 L·m -2 ·h -1 (0.5 MPa) and 91.2%, respectively. Thus, the newly synthesized polymer is proven to be a promising material for dye separation with positive charges.
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Scientific Reports
·
2015
·Vol. 5
·期 1
·1-17
·
IF 5.578
Li Jian-Long,Zhao Wei,Zhou Chen,Zhang Ya-Xuan,Li Hong-Mei,Tang Ya-Ling,Liang Xin-Hua,Chen Tao,Tang Ya-Jie
Herein is a first effort to systematically study the significance of carbon-sulfur (C-S) and carbon-amine (C-NH) bonds on the antitumor proliferation activity of podophyllum derivatives and their precise mechanism of apoptosis. Compared with the derivative modified by a C-NH bond, the derivative modified by a C-S bond exhibited superior antitumor activity, the inhibition activity of target proteins tubulin or Topo II, cell cycle arrest and apoptosis induction. Antitumor mechanistic studies showed that the death receptor and the mitochondrial apoptotic pathways were simultaneously activated by the C-S bond modified aromatic heterocyclic podophyllum derivatives with a higher cellular uptake percentage of 60–90% and induction of a higher level of reactive oxygen species (ROS). Only the mitochondrial apoptotic pathway was activated by the C-NH bond modified aromatic heterocyclic podophyllum derivatives, with a lower cellular uptake percentage of 40–50%. This study provided insight into effects of the C-S and C-NH bond modification on the improvement of the antitumor activity of Podophyllum derivatives.
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