Analytical Methods
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2014
·Vol. 7
·期 1
·260-265
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IF 1.938
Jianying Qu,Yong Wang,Ying Dong,Zhuanying Zhu,Huanhuan Xing
In this work, water-soluble ZnS:Ni/ZnS quantum dots (QDs) with core/shell structure were obtained successfully using mercaptoacetic acid as dressing agent, which were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, atomic force microscopy and transmission electron microscopy. A highly sensitive and stable electrochemical sensor was developed by immobilizing L-cysteine and ZnS:Ni/ZnS QDs on the surface of glassy carbon electrode. The sensor showed excellent catalytic activity to catechol (CC). Experimental results showed that the oxidation peak current of CC was linear over the range from 0.5 to 100 μM, and the detection limit (S/N = 3) for CC was 32 nM. The developed sensor was successfully used for determination of CC in lake water samples with satisfactory recoveries.
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COLLOID AND POLYMER SCIENCE
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2014
·Vol. 293
·期 2
·473-479
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IF 2.41
Jiang Yanping,Li Xianggao,Wang Shirong,Xiao Yin
In this paper, we reported a novel non-aqueous electrorheological (ER) fluid structured by TiO 2 nano-particle-modified poly (methyl methacrylate) (PMMA/TiO 2 ) dispersed in low viscosity Isopar L and its electrorheological behaviors were researched. Titanium dioxide nano-particles modified with poly (methyl methacrylate) were prepared via in situ polymerization and characterized by Fourier transform infrared, thermogravimetry, and transmission electron microscopy. The thickness of the cladding layer of nano-titanium dioxide surface was about 2∼3 nm, and the cladding rate was 1.437 %. A non-aqueous electrorheological (ER) fluid was constituted by PMMA/TiO 2 particles dispersed in Isopar L. The influence of the electric field intensity, the mass concentration of the PMMA/TiO 2 , and the temperature on the electrorheological properties of ER fluid were discussed, respectively. The research results showed that the ER fluid performed a well rheological property when an external electric field was applied, and with the increase of the electric field intensity, from 0 to 4.5 kV/mm, the shear stress was increased from about 3 to 30 Pa. Meanwhile, the electrorheological effect and shear stress were also strengthened with temperature elevated, and the mass concentration of PMMA/TiO 2 particles increased in dispersed system, respectively.
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FITOTERAPIA
·
2014
·
IF 2.216
Yan Xie,Huilin Luo,Jingze Duan,Chao Hong,Ping Ma,Guowen Li,Tong Zhang,Tao Wu,Guang Ji
Aim Total flavones of Hippophae rhamnoides L. (TFH) have a clinical use in the treatment of cardiac disease. The pharmacological effects of TFH are attributed to its major flavonoid components, isorhamnetin , kaempferol , and quercetin . However, poor oral bioavailability of these flavonoids limits the clinical applications of TFH. This study explores phytic acid (IP 6 ) enhancement of the oral absorption in rats of isorhamnetin, kaempferol, and quercetin in TFH. Methods In vitro Caco-2 cell experiments and in vivo pharmacokinetic studies were performed to investigate the effects of IP 6 . The aqueous solubility and lipophilicity of isorhamnetin, quercetin, and kaempferol were determined with and without IP 6 , and mucosal epithelial damage resulting from IP 6 addition was evaluated by MTT assays and morphology observations. Results The P app of isorhamnetin, kaempferol, and quercetin was improved 2.03-, 1.69-, and 2.11-fold in the presence of 333 μg/mL of IP 6 , respectively. Water solubility was increased 22.75-, 15.15-, and 12.86-fold for isorhamnetin, kaempferol, and quercetin, respectively, in the presence of 20 mg/mL IP 6 . The lipophilicity of the three flavonoids was slightly decreased, but their hydrophilicity was increased after the addition of IP 6 in the water phase as the logP values of isorhamnetin, kaempferol, and quercetin decreased from 2.38 ± 0.12 to 1.64 ± 0.02, from 2.57 ± 0.20 to 2.01 ± 0.04, and from 2.39 ± 0.12 to 1.15 ± 0.01, respectively. The absorption enhancement ratios were 3.21 for isorhamnetin, 2.98 for kaempferol, and 1.64 for quercetin with co-administration of IP 6 (200 mg/kg) in rats. In addition, IP 6 (200 mg/kg, oral) caused neither significant irritation to the rat intestines nor cytotoxicity (400 μg/mL) in Caco-2 cells. Conclusions The oral bioavailability of isorhamnetin, kaempferol, and quercetin in TFH was enhanced by the co-administration of IP 6 . The main mechanisms are related to their enhanced aqueous solubility and permeability in the presence of IP 6 . In summary, IP 6 is a potential absorption enhancer for pharmaceutical formulations that is both effective and safe.
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BIOSENSORS & BIOELECTRONICS
·
2013
·
IF 5.437
Qingqing Wang,Xiangyang Yu,Guoqing Zhan,Chunya Li
Using N-acetyl- l -cysteine as a stabilizer, well water-dispersed, high-quality and stable CdHgSe quantum dots were facilely synthesized via a simple aqueous phase method. The as-prepared N-acetyl- l -cysteine capped CdHgSe quantum dots were thoroughly characterized by transmission electron microscopy , X-ray diffraction spectroscopy and FTIR. A fluorescent sensor for selective determination of copper ions was developed using N-acetyl- l -cysteine capped CdHgSe quantum dots as fluorescent probe . The fluorescence intensity of N-acetyl- l -cysteine capped CdHgSe quantum dots decreased when interacted with copper ions due to the formation of coordination complex and aggregates. The method possesses high selectivity and is not influenced by some potential interferences such as Ag + , Zn 2+ , Co 2+ and Ni 2+ . Under the optimal conditions, the change of fluorescence intensity (Δ I ) was linearly proportional to the concentration of copper ions in the range of 1.0×10 −9 –4.0×10 −7 mol L −1 , with a detection limit as low as 2.0×10 −10 mol L −1 (S/N=3). The developed method had been successfully employed to determine Cu 2+ in shrimp and South-lake water samples, and the results were verified by atomic absorption spectroscopy . The fluorescent sensor was demonstrated to be selective, sensitive and simple for copper ion determination, and promise for practical applications.
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JOURNAL OF ELECTROANALYTICAL CHEMISTRY
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2015
·
IF 2.729
Hongbo Li,Daye Chen,Hongmei Wang,Jing Li,Wei Wang
A novel photoelectrochemical (PEC) sensor for l -cysteine was fabricated using in situ plasmonic silver nanoparticles modified hierarchically structured zinc oxide. The fabricated PEC sensor was based on Ag–S coordination chemistry and the collective oscillatory motion of electrons resulting from the coherent excitation of the “free” electrons in the conduction band of silver nanoparticles . The energetic electrons from the surface plasmon of the silver nanoparticles may be injected into the conduction band of the hierarchically structured zinc oxide and then fast transferred to the ITO electrode. However, the enhanced photocurrent produced by the plasmonic silver nanoparticles can be efficiently inhibited due to the bonding of Ag–S upon the simulated sunlight irradiation and at the bias voltage of 0.2 V. Under the optimized condition, the fabricated PEC sensor was linear with the concentration of l -cysteine in the range from 0.67 to 34.77 pmol L −1 with the detection limit of 0.21 pmol L −1 . The presence of definite concentration of conventional species did not interfere in the detection of l -cysteine and the results agreed well with those obtained by HPLC. This novel plasmonic PEC sensor has good performances in high sensitivity, good selectivity, easy operation, economy, short detection time, and portability. The strategy of localized surface plasmon resonance by in situ generation of silver nanoparticles provides an alternative way to construct a PEC sensor of l -cysteine.
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CARBOHYDRATE POLYMERS
·
2014
·
IF 3.916
Yadong Liu,Xiaosa Jin,Xiaosa Zhang,Miaomiao Han,Shengxiang Ji
Three amphiphilic poly( N -acryloyl- l -amino acid) grafted celluloses were prepared by RAFT polymerization of N -acryloyl- l -amino acid, where amino acid is alanine, proline or glutamic acid, onto cellulose backbones. The chemical structure and solution properties of the brush copolymers were characterized with FTIR, NMR and wide angle X-ray diffraction (WAXD). The thermal stability of the brush copolymers was estimated by thermal gravimetric analysis (TGA). Circular dichroism (CD) and specific rotation measurements confirmed that these grafted celluloses had characteristic chiroptical properties. The amphiphilic brush copolymers self-assembled into micelles in the aqueous solution as confirmed by transmission electron microscopy (TEM) and dynamic light scattering (DLS) analyses. The micellar aggregates showed a tunable pH-responsive property and disaggregated to form unimolecular micelles at higher pH in diluted solutions. The brush copolymers have potential applications in controlled drug release and high-performance liquid chromatography, and so forth.
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MICROPOROUS AND MESOPOROUS MATERIALS
·
2015
·
IF 3.453
Songlin Xue,Hong Jiang,Zhaoxiang Zhong,Ze-Xian Low,Rizhi Chen,Weihong Xing
A new Pd@ZIF-L hybrid catalyst having a unique crosshair-star shape with a size of about 20 μm was synthesized, in which a two-dimensional layered zeolitic imidazolate framework-L (ZIF-L) was used as a support to immobilize palladium nanoparticles via an assembly method. The hybrid catalyst with unique cushion-shaped cavities between layers with a size of 6.64 Å can be used for the diffusion of specific reactants not achievable by other ZIF systems such as ZIF-8. The crystal structure and morphology of Pd@ZIF-L are strongly dependent on the synthesis conditions. Palladium nanoparticles with an average size of 3 nm are homogeneously encapsulated in the ZIF-L crystals. The as-synthesized Pd@ZIF-L catalyst favors the conversion of alkenes with larger molecular sizes, and exhibits excellent molecule-size-selectivity and anti-leaching performance.
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JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY
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2015
·Vol. 53
·期 21
·2469-2480
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IF 3.113
Yong Deng,Xi Wang,Qiulin Yuan,Mengxiang Zhu,Ying Ling,Haoyu Tang
A series of side-chain-functionalized α-helical polypeptides, i.e., poly(γ-4-(3-chloropropoxycarbonyl)benzyl- L -glutamate) (6) have been prepared from n-butylamine initiated ring-opening polymerization (ROP) of γ-4-(3-chloropropoxycarbonyl)benzyl- L -glutamic acid-based N -carboxyanhydride. Polypeptides bearing oligo-ethylene-glycol (OEG) groups or 1-butylimidazolium salts were prepared from 6 via copper-mediated [2+3] alkyne-azide 1,3-dipolar cycloaddition or nuleophilic substitution, respectively. CD and FTIR analysis revealed that the polymers adopt α-helical conformations both in solution and the solid state. Polymers bearing OEG (m = 3) side-chains showed reversible LCST-type phase transition behaviors in water while polymers bearing 1-butylimidazolium and I − counter-anions exhibited reversible UCST-type transitions in water. Variable-temperature UV-vis analysis revealed that the phase transition temperatures ( T pt s) were dependent on the main-chain length and polymeric concentration. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53 , 2469–2480
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BIOSENSORS & BIOELECTRONICS
·
2014
·
IF 6.451
Ai-Ling Hu,Yin-Huan Liu,Hao-Hua Deng,Guo-Lin Hong,Ai-Lin Liu,Xin-Hua Lin,Xing-Hua Xia,Wei Chen
A novel fluorescent hydrogen peroxide sensor was developed based on the peroxidase-like activity of cupric oxide nanoparticles . Cupric oxide nanoparticles effectively catalyzed the decomposition of hydrogen peroxide into hydroxyl radicals . Then terephthalic acid was oxidized by hydroxyl radical to form a highly fluorescent product. The linear range of hydrogen peroxide estimated to be 5.0×10 −6 –2.0×10 −4 M with a detection limit of 3.4×10 −7 M. Moreover, this detection system enabled the sensing of analytes which can enzymatically generate hydrogen peroxide. By coupling the oxidation of glucose or l -lactate catalyzed by their corresponding oxidase enzymes with terephthalic acid oxidation catalyzed by cupric oxide nanoparticles, sensitive assays of glucose and l -lactate with detection limits of 1.0×10 −6 and 4.5×10 −8 M were realized. The successful applications of this approach in human serum samples have also been demonstrated.
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Journal of Materials Chemistry B
·
2016
·Vol. 4
·期 19
·3339-3350
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IF 4.872
Weijun Xu,Junmin Qian,Yaping Zhang,Aili Suo,Ning Cui,Jinlei Wang,Yu Yao,Hejing Wang
The most common in vitro cell culture platform, standard two-dimensional (2D) monolayer cell culture, often fails to mimic the tumor microenvironment, while animal models complicate research on the effect of individual factors on cell behaviors. Both are unsatisfactory in the research of molecular mechanisms of tumor development and progression and the discovery and development of anticancer drugs. In vitro three-dimensional (3D) cell culture can partially simulate in vivo conditions and 3D-cultured cancer cells can recapture many essential features of native tumor tissues. In this study, to mimic the in vivo breast tumor microenvironment, novel reduction-responsive poly(Nε-acryloyl L-lysine) (pLysAAm) hydrogels were synthesized by rapid photo-polymerization of Nε-acryloyl L-lysine and using N,N′-bis(acryloyl)-(L)-cystine as a crosslinker, and their physicochemical properties were characterized systemically. The results showed that the pLysAAm hydrogels were formed within 93 s under UV irradiation and exhibited almost total elastic recovery from compressions as high as 75%. The lyophilized hydrogel samples displayed a highly porous structure with interconnected pores, had an equilibrium swelling ratio of about 20, and were degraded faster in a glutathione-containing solution than in PBS solution. The biological versatility of the pLysAAm hydrogels was demonstrated by both in vitro MCF-7 cell culture and in vivo tumor formation. Compared to cells cultured as 2D monolayers, the 3D-cultured cells presented 3D cell morphology, exhibited better cell viability, expressed higher levels of pro-angiogenic factors, and showed significantly greater migration and invasion abilities. The results from assay of tumorigenicity in nude mice and histologic analysis demonstrated the enhanced tumorigenic and angiogenic capabilities of the MCF-7 cells pre-cultured in pLysAAm hydrogels. These findings suggest that pLysAAm hydrogels may be used to bridge the gap between standard in vitro cell cultures and living tissues, aid breast cancer research, and help researchers to develop novel anticancer therapeutics.
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INTERNATIONAL JOURNAL OF POLYMER ANALYSIS AND CHARACTERIZATION
·
2017
·
IF 0
Jiale Cui,Zhihua Zhou,Yun Yang,Wenjuan Liu,Yunfei Zhao,Cheng Peng,Tianlong Huang,Hu Zhou,Lihua Liu,Qiao Zhang
In order to improve hydrophilicity and settle the acidity in hydrolysis, a novel ethanediamine (EDA) and maleic anhydride (MAH) modified poly(D,L-lactide-co-glycolide) (PLGA) polymer (EMPLGA) was synthesized. Fourier Transform Infrared Spectrometer (FTIR), Gel Permeation Chromatography (GPC), Nuclear Magnetic Resonance (1HNMR), titration and the water contact angles were employed to characterize the synthesized polymer. The effects of various polymerization conditions on weight average molecular mass (Mw), polydispersity index (PDI) and anhydride content of MPLGA were investigated. The degradation behaviors of PLGA, MPLA and EMPLGA were also studied by observation of the changes of the pH value of incubation medium, molecular weight and weight loss ratio for a time interval of 25 days in-vitro, respectively. The results showed that MPLGA with high anhydride content was successfully obtained by directly ring-opening polymerization and ethanediamine was further grafted onto MPLGA, and there is almost unchanged in Mw between MPLGA and EMPLGA polymers. The introduction of anhydride and amino groups improved the hydrophilicity of PLGA. A uniform degradation of EMPLGA was observed in comparison with an acidity-induced auto-accelerating degradation featured by PLGA and MPLGA. The results revealed that the introduction of ethanediamine into PLGA has weakened or neutralized the acidity of PLGA degradation products.
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Materials Science & Engineering C-Materials for Biological Applications
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2017
·
IF 4.164
Heyu Li,Gareth R. Williams,Junzi Wu,Haijun Wang,Xiaozhu Sun,Li-Min Zhu
In this work, we aimed to develop new materials to reduce the secondary injuries which can be imparted when replacing wound dressings. Electrospun fibers based on the thermoresponsive polymer poly( N -isopropylacrylamide) (PNIPAAm), poly( l -lactic acid- co -ɛ-caprolactone) (PLCL), and the antibiotic ciprofloxacin (CIF) were prepared. The water contact angle of fibers made from a blend of PNIPAAm and PLCL changed dramatically when the temperature was increased above 32 °C. Sustained release of CIF from the formulations was observed over > 200 h. Moreover, L929 fibroblasts could proliferate on the fibers, indicating their biocompatibility. The CIF-loaded fibers were found to have potent antibacterial activity against E . coli and S . aureus . In vivo tests on rats indicated that CIF-loaded thermosensitive fibers have enhanced healing performance compared to CIF-loaded PLCL fibers or a commercial gauze. Electrospun PNIPAAm/PLCL fibers loaded with CIF thus have great promise in the development of new wound dressing materials.
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