Chem. J. Chinese Universities

Cover and Content of Chemical Journal of Chinese Universities Vol.34 No.4(2013)

2013, 34(4): 0-0.

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Fabrication of Polymeric Hollow Structure by Electrospinning

BAI Fan, WU Jun-Tao, GONG Guang-Ming, SUN Na, ZHAO Yong, JIANG Lei

2013, 34(4): 751-759. doi:10.7503/cjcu20120734

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Polymeric hollow micro/nano-material has a potential application prospects in a lot of fields, by virtue of its unique physical and chemical properties. Electrospinning is a kind of methods to prepare nanoscale continuous filament. In recent years, using electorspinning to construct the hollow micro/nano-material efficiently and simply has received much attention. This article reviews the progress in preparation of polymeric hollow fibers and spheres by electrospinning, and prospects its development in different functional material fields.

Preparation of Basic Fuchsin Modified Magnetic Microspheres and Its Application in Isolation of Mycobacterium

CHA Dong-Mei, HAN Zhao-Hui, MA Tian, LI Bu-Hai, LIU Guo-Quan, ZHU Wei

2013, 34(4): 760-762. doi:10.7503/cjcu20120906

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Two kinds of methods were used to prepare basic fuchsin(BF) modified magnetic nanoparticles. The obtained BF modified nanoparticles(MNP-1 and MNP-2) were characterized using transmission electron microscope(TEM) and Fourier transformation infrared(FTIR) spectroscopy before used to adsorb mycobacterium from Staphylococcus aureus and Escherichia coli(E. coli). The effects of pH, adsorption time, concentration of bacteria, temperature, ionic strength and adsorbent dosage on the adsorption of bacterium were studied. The results show that both MNP-1 and MNP-2 have good selectivity for mycobacterium, and can be easily separated by external magnetic field. Under the optimized conditions, the highest adsorption rate for mycobacteria were 65%(MNP-1) and 85%(MNP-2), while only 20% of Staphylococcus aureus and 10% of E. coli can be adsorbed under the same conditions. The adsorption capacity of MNP-1 and MNP-2 for mycobacteria was 1.48?0¹⁰ and 3.25?0¹⁰ cfu/g, respectively.

Oxidation, Modification and Dispersibility of Single-walled Carbon Nanohorns

LI Xue-Quan, SUN Cheng-Yu, ZHAO Qian, WU Zhi-Shan, XU Dan-Ke, ZHONG Wen-Ying

2013, 34(4): 763-770. doi:10.7503/cjcu20121146

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Single-walled carbon nanohorns(SWNHs) are new materials that are similar to single-walled carbon nanotubes(SWNTs) but have more comparative advantages than SWNTs. The size of SWNHs matches the condition for achieving enhanced permeability and retention(EPR) effect. The non-cytotoxicity makes SWNHs potentially applicable in drug delivery and electrochemical biosensing. However, it's hard to apply SWNHs in water since the surface of SWNHs is hydrophobic. In this article, we carried out systematic research to improve the dispersibility and biocompatibility of SWNHs. The effects of pH value, salt concentration and Tween 80 on the dispersion of SWNHs were investigated. The results showed that SWNHs dispersed well in water at the pH values of 6—10 and high salt concentration had substantial obstacle to their dispersion. It can be deduced that surface Zeta potential is an important factor on the dispersion of SWNHs. Tween 80 helped SWNHs well dispersed in buffers. These results are important for us to understand the dispersion of SWNHs mechanism in aqueous solution. In order to find the best way to improve the dispersion and biocompatibility of SWNHs, three oxidation methods of SWNHs were studied including concentrated nitric acid refluxing, H₂O₂ oxidation assisted by Hg lamp and H₂O₂ oxidation assisted by Xe lamp. As a result, H₂O₂ oxidation assisted by Xe lamp in 1 h is the most effective method because it generats large amount of oxygenated groups on the surface of SWNHs which are of great help for their dispersion. In order to improve the biocompatibility of SWNHox, we chose carboxyl polyethylene glycol distearoyl phosphatidylethanolamine(DSPE-PEG-COOH) to modify SWNHox. Different concentrations of DSPE-PEG-COOH were used in water and phosphate buffer solution(PBS) followed by determining the Zeta potentials and monitoring the coagulation times. The result showed that 0.25 mg/mL was the optimal concentration of DSPE-PEG-COOH to achieve the best dispersion in PBS. Our study lays an important experimental basis for carbon nanohorns to be used in drug delivery systems and biosensors in the future.

Growth and Gas Permeation Properties of Continuous L-type Zeolite Membrane on Stainless Steel Net

ZHANG Jin-Lei, ZHAO Qing, LIU Jia, SUN Fu-Xing

2013, 34(4): 771-775. doi:10.7503/cjcu20120988

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Growth of L-type zeolite membrane on stainless steel net by the secondary hydrothermal growth was studied under different conditions. The effects of the alkalinity of the reaction solution and the reaction time on the formation of L-type zeolite membrane were discussed via the observation through scanning electron microscopy technique. The continuous uniform phase-pure L-type zeolite membrane was obtained with a thickness of about 20 μm. Single gas permeation measurement on the as-synthesized L-type membrane demonstrates that the permeance of N₂ and H₂ are 8.39×10^-8 and 6.96×10^-7 mol·m^-2·s^-1·Pa^-1 respectively, indicating an ideal selectivity for H₂/N₂ of 8.3. Binary gas permeation measurement demonstrates that the increase of temperature would strengthen the permeation of N₂ and H₂, but decrease the separation factor of H₂/N₂.

Synthesis and Characterization of Lipophilic, Near-IR Absorbing Metallobacteriochlorins

SUN Er-Jun, CHEN Chih-Yuan, LINDSEY Jonathan S.

2013, 34(4): 776-781. doi:10.7503/cjcu20120865

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The metalation of bacteriochlorins, an ostensibly simple reaction, has proved more difficult than the metalation of porphyrins and chlorins. The traditional synthesis method to prepare metalloporphyrins(metal acetate in heated N,N-dimethyl formamide) is not generally applied to the synthesis of metallobacteriochlorins. In this paper, by treating bacteriochlorins 3,13-bis(ethoxycarbonyl)-2,12-diheptyl-8,8,18,18-tetramethylbacteriochlorin(HBC) or 3,13-bis(ethoxycarbonyl)-2,12-diheptyl-5-methoxy-8,8,18,18-tetramethylbacteriochlorin(MeOBC) in THF with a strong base(NaH) followed by a metal reagent MX_n(M=Ni, Cu, Pd), five new metallobacteriochlorins were obtained. The as-synthesized metallobacteriochlorins were characterized by ¹H NMR spectroscopy and mass spectrometry, and their absorption and fluorescence spectra were studied. For a bacteriochlorin, the insertion of a metal typically causes a bathochromic shift of the position of the long-wavelength absorption band. Both bacteriochlorin ligands and Zn complexes exhibit Q_y(0,0) fluore-scence, and the Cu and Ni bacteriochlorin complexes exhibit no fluorescence.

Effect of Preparation Process on the Synthesis of Composite Molecular Sieves by Pre-loading Raw Method

ZHANG Qiang, XU Shao-Jun, MENG Xiao-Jing, YANG Wen-Hui, LI Chun-Yi, SHAN Hong-Hong, YANG Chao-He

2013, 34(4): 782-787. doi:10.7503/cjcu20120689

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The core/shell binary structure composite molecular sieves have been synthesized by loading raw materials method. The effects of types of aluminium source and preparation process were investigated. The synthesized samples were characterized by X-ray diffraction(XRD), scanning electron microscopy(SEM) and energy dispersive spectrometry(EDS). Using iso-propanol aluminum as the aluminium source, there is no SAPO-5 phase in short crystallization time; prolonging crystallization time increases the crystallinity of SAPO-5; the aging of the different reaction mixture at room temperature can cause a rapid formation of SAPO-5 sieve. The choice of the content of water in gel and mixing manners are dictated by types of aluminium source. Using pseudoboehmite as aluminium source, at the same pretreated temperature of coating phosphorus and preparation process, the sieve with higher degree of crystallinity was obtained.

Preparation of Up-conversion Luminescent Material Labeled Antibody and Its Application in Immunohistochemistry

CHEN Ying, LI Fei-Fei, LI Chun-Guang, PAN Qing-Zhi, CUI Man-Hua

2013, 34(4): 788-793. doi:10.7503/cjcu20120667

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The up-conversion luminescent material for optically written display, NaGdF₄: Yb³⁺,Er³⁺ up-conversion nanoparticies(UCNPs) were prepared under microwave irradiation. The particle size was about 65 nm and the samples exhibited green(550 nm) fluorescence excited by a 980 nm diode laser. The UCNPs@SiO₂-NH₂ nanocomposites, the size of which was 70 nm, were prepared and conjugated with polyclonal antibidy. Then, the ability of polyclonal antibody fluorescent probes was detected to recognize the expression of tissue inhibitor of metalloproteinases-4(TIMP-4) in the endometrial gland cells by immunohistochemistry. The results show that the as-prepared UCNPs have uniform shape and size distribution. The UCNPs@SiO₂-NH₂ nanocomposites offer some distinct advantages, such as good distribution and water-solubility, strong and stable upcoversion fluorscence as well as significant auto-fluorescence from biological tissues resting in low signal to background ratio, and are potentially to apply to detect the expression of protein in tissues at 980 nm excitation.

Hydrothermal Preparation and Luminescence Properties of NaGd(MoO₄)₂: Dy³⁺,Eu³⁺ White-light Phosphors

JIANG Ying-Ying, LIU Gui-Xia, WANG Jin-Xian, DONG Xiang-Ting, YU Wen-Sheng

2013, 34(4): 794-799. doi:10.7503/cjcu20120662

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Dy, Eu co-doped NaGd(MoO₄)₂ white-light phosphors were prepared by a simple glutamic acid-assisted hydrothermal method. X-Ray diffraction(XRD) patterns show that the samples are tetragonal phase NaGd(MoO₄)₂. Scanning electron microscopy(SEM) images show that the as-prepared particles have an octagonal shape with each side length of about 2 μm. In the fluorescence spectra of NaGd(MoO₄)₂: Dy,Eu, it is found that the emission intensity of Eu³⁺ increased and the emission intensity of Dy³⁺ decreased with increasing the amount of Eu³⁺ and maintaining the concentration of Dy³⁺. The energy transmission of Dy³⁺-Eu³⁺ is observed. From Commission Internationale de L'Eclairage(CIE) chromaticity diagram, it is noted that white light can be achieved in NaGd(MoO₄)₂: 4%Dy³⁺,0.9%Eu³⁺ phosphor, the CIE color coordinates(0.338, 0.281) are near to the standard color coordinates(0.33, 0.33).

Synthesis of Nitrogen-doped Graphene and Its Electrocatalytic Performance Toward Oxygen Reduction Reaction

LI Jing, WANG Xian-Bao, YANG Jia, YANG Xu-Yu, WAN Li

2013, 34(4): 800-805. doi:10.7503/cjcu20120658

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A series nGs with different electrocatalytic abilities toward oxygen reduction reaction(ORR) was prepared via a two-steps pyrolysis method by controlling the reaction temperature on the physical mixture of graphene oxideand urea. Transmission electron microscopy and scanning electron microscopy display nG with highly wrinkled and overlapping structures. X-ray photoelectron spectroscopy shows that nitrogen is successfu-lly doped in graphene with the formation of pyridinic N, pyrrolic N and graphitic N, and the maximum nitrogen content is 6.6%(molar fraction). Cyclic voltammogram and rotating disk electrode measurement show that nGs exhibit high electrocatalytic activity with an onset potential of 0.1 V in an acid electrolyte. Moreover, the nGs catalyzed oxygen reduction revealed a favorable formation of water via a four-electron pathway and excellent stability over Pt/C catalyst. Furthermore, the nG obtained at 200 ℃ in the first pyrolysis step displays the best catalytic perfor-mance.

Novel Nucleic Acid Signal Amplification Liquid Crystal Biosensor for Detection of p53 Gene Mutation

FAN Yu-Xia, TAN Hui, LIU Ling-Wei, WU Zhao-Yang, SHEN Guo-Li, YU Ru-Qin

2013, 34(4): 806-812. doi:10.7503/cjcu20121120

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A novel nucleic acid liquid crystal biosensor was constructed for the detection of the p53 mutant gene based on the branched nucleic acid hybridization reaction and the orientational transition of liquid crystal. Herein, a specific target DNA sequence was used as an initiator, the three different hairpin probes as dendritic monomers, and the branched-like DNA with controllable molecular size and weight could be formed by changing the concentrations of the monomers and the reaction time under mild conditions. And then the branched-like DNA was hybridized with the capture DNA sequences on the glass substrate. Making use of unique birefringent properties of liquid crystal molecules, the sensor could get an enhanced polarization response signal, and achieved the rapid and specific detection low to 1 nmol/L mutant DNA strands. This simple and sensitive detection method in the detection of DNA has greater practicality, and is expected to be promoted.

Screening of α-Glucosidase Inhibitors in Ginkgo Biloba Extract Using Ultrafiltration LC-ESI-MSⁿ

LIU Yang, ZHOU Hui, LIU Shu, LIU Zhi-Qiang

2013, 34(4): 813-818. doi:10.7503/cjcu20121098

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In vitro α-glucosidase inhibition assays and ultrafiltration liquid chromatography coupled to electrospray ionization tandem mass spectrometry(ultrafiltration LC-ESI-MSⁿ) were combined to screen α-glucosidase inhibitors from ginkgo biloba extract. The enzyme inhibition studies were carried out spectrophotometrically in a 96-well microplate reader. Using 4-nitrophenyl α-D-glucopyranoside(PNPG) as the substrate and acarbose as a positive control, α-glucosidase inhibitory activity of the five kinds of Chinese herb extracts which rich in flavonoids were determined, the results showed that the ginkgo biloba extract has the strongest the α-glucosidase inhibitory activity. Ultrafiltration LC-ESI-MSⁿ was used to screen and identify α-glucosidase inhibitors from ginkgo biloba extract. As a result, four compounds were identified as α-glucosidase inhibitors in the ginkgo biloba extract, and their structures were confirmed to be quercetin, apigenin, kaempferol and isorhamnetin by ESI-MS.

Rapid Analysis of Complex Samples by GC-MS with Immune Algorithm

MEI Zhen, CAI Wen-Sheng, SHAO Xue-Guang

2013, 34(4): 819-822. doi:10.7503/cjcu20120991

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Immune algorithm(IA) has been proved to be an efficient tool for extracting the information of the components from overlapping signals. Based on IA, a method for rapid analysis of mixture samples via gas chromatography-mass spectrometry(GC-MS) was developed. In the method, the measurement of GC-MS was achieved with a very fast temperature program, and then IA was adopted to obtain the information of each component in the overlapping signal. Taking the mass spectra of all the possible components as the input of the algorithm, the concentration of each component at each retention time can be obtained. The concentrations of all the retention times form the chromatographic profiles of the components. Owing to the character of IA, the extracted concentration for the components that does not really exist in the sample will be zero. GC-MS data of 16-organophosphorus pesticides mixture was investigated by the method. The results show that the chromatographic information of all the components can be extracted from the overlapping signal eluted in 10 min.

Low-background Electrochemical DNA Biosensor Using an Electrically Neutral Osmium Complex as Hybridization Indicator

DING Ying-Tao, WANG Li-Heng, LI Fu-Xiao, GAO Feng, GAO Fei, WANG Qing-Xiang

2013, 34(4): 823-828. doi:10.7503/cjcu20120705

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The interaction between an electrically neutral osmium complex Os(DPPZ)(PC)(H₂O) (DPPZ=dipyrido(3,2-a,2',3'-c)phenazine, PC=2,6-pyridine dicarboxylic acid) and DNA was investigated by UV absorption spectroscopy and electrochemical methods. The hypochromic and red-shift effects of the characteristic absorption peak of Os(DPPZ)(PC)(H₂O) after interaction with DNA suggested that the complex bound to DNA via an intercalative mode, which was testified by the positive shift of the formal potential of the complex in cyclic voltammetric experiments. When the complex was utilized as a hybridization indicator for the detection of CaMV35S promoter gene fragments, no electrochemical response was observed on the probe of DNA modified electrode. A sensitive electrochemical signal, however, was obtained on the hybridized electrodes, suggesting that the DNA biosensor possessed a high signal-to-noise ratio. The complementary target sequence could be quantified over the range from 8.0?0^-10 mol/L to 2.8?0^-9 mol/L. The hybridization specificity experiments further indicated that the biosensor could well discriminate the complementary sequences from the base-mismatched and the non-complementary sequences.

Influence of Caffeine on the Sedative Effects of Promethazine Based on Pharmacokinetics and Metabolomics

HUANG Min, GAO Jian-Yi, ZHAI Zhi-Gang, LIANG Qiong-Lin, WANG Yi-Ming, BAI Yan-Qiang, LUO Guo-An

2013, 34(4): 829-836. doi:10.7503/cjcu20120702

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Pharmacokinetic and metabolomic methods were employed to investigate the influence of caffeine on the sedative effects of promethazine. First, a space flight vigilance tasks simulation system and Standford sleepiness scale(SSS) were used to compare the effect of single administration of promethazine and combination administration with caffeine on the cognitive function of volunteers. Then software named Kinetica was used to calculate some of the important pharmacokinetic parameters of promethazine before and after the combination. And the possible influencing factors were discussed. Finally, a metabolomic method was applied to identify the potential biomarkers between two groups. The results suggest that caffeine could confront the sedative effects of promethazine and so improve the decreased cognitive function, which might be induced by the accelerated metabolism of promethazine and the altered dopamine, norepinephrine and epinephrine related pathways. This study provides a new approach for the research of combination administration of promethazine and caffeine.

Silver Nanoparticles Preparation Using Antioxidant Propyl Gallate and Its Analytical Application

WANG Ping, NI Yong-Nian

2013, 34(4): 837-840. doi:10.7503/cjcu20120696

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Silver nanoparticles were synthesized based on the chemical reduction between propyl gallate(PG) and silver nitrate in the presence of cetyltrimethylammonium bromide(CTAB). The experimental conditions, including reaction time, concentration of sodium hydroxide, temperature and concentration ratio of PG to Ag⁺, were investigated. The silver nanoparticles were characterized by scanning electron microscope(SEM), and it showed that the nanoparticles were spherical shape. The reduction of Ag⁺ to silver nanoparticles produced very intense surface plasmon resonance peak of silver nanoparticles. An absorbance band in the range of 400—450 nm was observed by UV-Vis spectrophotometry with a maximum absorbance wavelength of 420 nm. The plasmon absorbance of silver nanoparticles allows the quantitative determination of some antioxidants, such as PG, butylated hydroxytoluene(BHT), butyl hydroxy anisole(BHA) and tertiary butyldroquinone(TBHQ). Their detection limits were 0.0752, 0.1242, 0.0693 and 0.0701 mg/L, respectively; and their corresponding linear ranges were 0.2—1.8, 0.2—3.4, 0.2—3.4 and 0.2—3.0 mg/L, respectively.

Detection of the Concentration of Glucose Solution Using Optical Waveguide Resonance Technology Combined with Colorimetry

GUAN Xiang-Yu, HUANG Mei-Zhen, WANG Yang, CHEN Chao, CAO Zhuang-Qi

2013, 34(4): 841-845. doi:10.7503/cjcu20120628

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Glucose is a major component of the carbohydrates in the bodies of animals and plants, and it is very important to determine its quantitative in many areas. In this work, the colorimetric method combined with a double-sided metal coated waveguide was used to constitute a high sensitive oscillation field optical waveguide sensor. The glucose solution was colored by mixing with the oxidase reagent and then was injected into the waveguide. The attenuated total reflection(ATR) absorption peaks could be obtained through angle scanning, with the 650 nm laser beam incidenting on the surface of the waveguide. And the concentration changes of the glucose solution could be detected according to the minimum value of the absorption peaks. The results show that the resolution to the concentration of solution of this method can reach to 111 nmol/mL.

Synthesis of Alkaloid Derivatives with Pyrroloindoline Skeleton Substituted on C3α-with Different Types of Arenes

KONG Chen, WANG Yu, WANG Xia, WANG Qiong, SONG Hao

2013, 34(4): 846-852. doi:10.7503/cjcu20120919

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Alkaloids bearing a pyrroloindoline skeleton substitutedon C3α-with different types of arenes form a major class of indole alkaloids which draw attention to synthetic chemists due to their broad range of potent biological activities. The derivatives 3a and 3b were obtained via a silver-promoted Friedel-Crafts reaction. Based on this method, derivatives 3a and 3b were found exhibiting micro-molar level activity against a variety of tumor cell, which are potential drug candidate. In order to study the drug-ability and structure-activity relationships(SARs) of these compounds, a series of natural product-like library analogues(4—17) was synthesized and the SARs of these compounds were studied. The structures of the compounds were confirmed by ¹H NMR, ¹³C NMR and HRMS. The research lays the foundation for pre-clinical studies of these compounds.

Binding Thermodynamics of p-Sulfonatocalix[4]arene with Quaternary Ammonium Dications

LI Zhen-Quan, HU Chun-Xiu, CHENG Yu-Qiao, XU Hui, CAO Xu-Long, SONG Xin-Wang, ZHANG Heng-Yi, LIU Yu

2013, 34(4): 853-857. doi:10.7503/cjcu20120897

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The stoichiometric ratio, binding modes, complex stability constants and thermodynamic parameters of p-sulfonatocalix[4]arene with three quaternary ammonium dication salts were studied in aqueous buffer solution(pH=7.20) by means of ¹H NMR spectroscopy and microcalorimetrical titration. The results obtained from NMR experiments suggest the 1: 1 stoichiometric ratio with different binding modes between host and guest. The results of the microcalorimetrical titration show that the complex stability constants of p-sulfonatocalix[4]arene with three quaternary ammonium dication salts are more than 10⁵ L/mol. Thermodynamically, the host-guest binding behavior are mainly driven by the favorable enthalpic changes, accompanied by the unfavorable entropic changes.

New Process for Preparation of Dronedarone Hydrochloride

LI Feng, TIAN Shuan-Hong, SONG Xiao-Feng, LI Wen-Yuan, CHENG Hua-Ying, LEI Ling-Zhi, ZHU Qin-Feng, JIN Chun-Hua, LI Shao-Hua

2013, 34(4): 858-862. doi:10.7503/cjcu20120862

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Dronedarone hydrochloride(1), a potent blocker of multiple ion, was approved for atrial fibrillation by Food and Drug Administration(FDA) in 2009. It's a modified synthetic analogue of amiodarone, which decreases lipophilicity and results in a shorter lifetime and lower tissue accumulation. Here a new process for compound 1 was achieved with 33% overall yield starting from commercial p-aminophenol(2). N-(4-oxocyclohexa-2,5-dien-1-yl)-methanesulfonamide(4) which was obtained by mesylation and oxidization from compound 2 reacted with methyl 3-oxoheptanoate followed by cyclization to afford N--methanesulfonamide(6). The inversion of compound 6 into the desired compound 1 was realized by hydrolyzation and chlorination followed by Friedel-Crafts reaction with N-butyl-N-(3-phenoxypropyl)-1-butanamine hydrochloride. This process is characterized by cheap and readily available materials, shorter procedures, mild reaction conditions and convenient work-up, making it practical in industry.

Direct Acetoxylation of Anilides Using Ion-supported [Bis(trifluoroacetoxy)iodo] benzene

ZHANG Ji-Zhen, ZHANG Mao-Lin, ZHAO De-Jian, WANG Ya-Zhen, JIA Hong-Bin

2013, 34(4): 863-869. doi:10.7503/cjcu20120852

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1-[4-Iodobenzamidoethyl]-3-methylimidazolium tetrafluoroborate was prepared by the reaction of 1-methylimidazole with N-(2-chloroethyl)-4-iodobenzamide, then anion exchange with NaBF₄ was performed in aqueous solution. The imidazolium tetrafluoroborates was oxidized to a novel ion-supported[bis(trifluoroacetoxy)iodo]benzene(BTI) reagent(solid) {1-[4-bis(trifluoroacetoxy) iodobenzamidoethyl]-3-methylimidazolium tetrafluoroborate} with amide linkage in a mixture of hydrogen peroxide and trifluoroacetic anhydride. The new reagent exhibited good stability in air or high humid atmosphere over several days.Direct acetoxylation of acetanilide using ion-supported(diacetoxyiodo)benzene(DIB) reagent and three ion-supported BTI reagents was studied. Due to low oxidation capacity of the ion-supported DIB reagent and low yields of its relative product, two ion-supported BTI reagents with amide linkage failed to carry out the acetoxylation reaction. However, 1-[4-bis(trifluoroacetoxy)iodobenzyl]-3-methylimidazolium tetrafluoroborat was an ideal oxidant. Treatment of various anilides with 1.1 mol of 1-[4-bis(trifluoroacetoxy)iodobenzyl]-3-methylimidazolium tetrafluoroborat and 1.0 mol of BF₃稯Et₂ in AcOH at room temperature afforded the corresponding para-acetoxylated products with high regioselectivity. After the acetoxylation, the reagent was transformed into ion-supported iodobenzene, which could be recovered and regenerated easily without lost of acetoxylation activity.

Screening, Radiolabeling and Biodistribution of Lung Tumor-targeting Peptide YC11 by in vivo Phage Display

LIANG Kun, CHU Tai-Wei

2013, 34(4): 870-874. doi:10.7503/cjcu20120995

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In vivo phage display was used to isolate tumor-targeting peptides. A cycloheptapeptide CSIHYPLSC(YC11) ligand targeting A549 human lung tumor was identified and radioiodinated. The labeled complex ¹³¹I-YC11 and ¹³¹I-NGR(control peptide) were isolated and purified by reverse phase high-performance liquid chromatography(RP-HPLC). The radiochemical purity was estimated to be better than 99%. The biodistribution results of ¹³¹I-YC11 and control peptide ¹³¹I-NGR in mice bearing A549 tumor demonstrated that the tumor-to-blood, tumor-to-heart, tumor-to-lung and tumor-to-liver uptake ratios of ¹³¹I-YC11 were 0.62, 2.06, 1.11 and 0.81, respectively, and slightly higher than those of ¹³¹I-NGR. The uptake of ¹³¹I-YC11 in tumor was 2.79%ID/g, more than that of ¹³¹I-NGR(1.61%ID/g). ¹³¹I-YC11 was more concentrated in A549 tumor than ¹³¹I-NGR. Conclusively, YC11 could be a potential lung cancer targeting agent.

Relationship Between Mn²⁺ in the Domain of Active Center of Chloroperoxidase and Enzyme Catalytic Performance

LI Hai-Yun, JIANG Yu-Cheng, HU Man-Cheng, LI Shu-Ni, ZHAI Quan-Guo

2013, 34(4): 875-880. doi:10.7503/cjcu20120973

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The coordination of heme propionate with Mn²⁺ in active center of chloroperoxidase(CPO) was confirmed by means of removing the metal ions using ethylene diamine tetraacetic acid(EDTA) ligand competition reaction and determining Mn²⁺ by graphite furnace atomic absorption and inductively coupled plasmas atomic emissive spectrometry assay. The presence of Mn²⁺ was found playing a role in holding the active domain and maintaining preferential conformation of CPO based on the UV-Vis absorption spectroscopy, circular dichroism(CD) analysis as well as chlorination activity and peroxidation activity measurement before and after Mn²⁺ being removed from CPO. The maximum absorption at 398 nm of CPO, which displayed by iron(Ⅲ) porphyrin and named Soret band, decreased with a concomitant decrease of catalytic activity after Mn²⁺ in CPO being removed(MCPO). The analysis of CD spectra indicated that α-helix structure was uncoiling in MCPO. Furthermore, it was found that the changing of micro-environment around heme in CPO active site was a reversible process, and the catalytic activity may be recovered when Mn²⁺ was reintroduced, but it was a slow dynamic process that needed nearly 100 h. Moreover, the chlorination activity and peroxidation activity of CPO was enhanced compared with that of native CPO when exogenous Ag⁺ and Cr³⁺ are introduced instead of Mn²⁺. Especially, the introduction of Cr³⁺ could not only recover the peroxidation activity of MCPO but also elevate the relative activity to 106%. The chlorination activity of MCPO was also recovered and even enhanced by the introduing of Ag⁺. This process was related to the electron transfer involved in the enzymatic catalytic cycle.

Structural Characterization of an Immunoactive Polysaccharide DNP-W1B from Dendrobium nobile Lindl.

WANG Jun-Hui, ZHA Xue-Qiang, PAN Li-Hua, LUO Jian-Ping

2013, 34(4): 881-885. doi:10.7503/cjcu20120883

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Dendrobium nobile Lindl.(Chinese name "Jin-Chai-Shi-Hu") is a species of Orchidaceae with distribution in Southeast Asia, southwest and south of China. In this work, a water-soluble heteropolysaccharide DNP-W1B with a molecular mass of 7.7×10⁵ and specific rotation of ²⁰_D=+81.3°(c 0.3, H₂O) was isolated from the stems of D. nobile Lindl. Monosaccharide composition analysis showed that DNP-W1B contained glucose, arabinose and galactose in a molar ratio of 6.2: 3.1: 0.9. The structural features of DNP-W1B were revealed by the combination of chemical and instrumental analysis, including IR, GC, methylation analysis and NMR. The results showed that DNP-W1B possessed a backbone of a disaccharide unit of with 33% branches at O-4 of (1→6)-linked β-D-glucopyranosyl residues. The side chains contained arabinosyl and galactosyl chains. Primary immunological tests in vitro indicated that it could stimulate LPS-induced B lymphocyte and Con A-induced T lymphocyte proliferation. Survey showed that DNP-W1B was a novel immunoactive polysaccharide compound from Dendrobium Sw.

Correlation of Enolase and the Maturation of SpeB in Streptococcus pyogenes

HU Shan, MA Chao, LI Xue-Ru, LI Ming, LIU Yan-Hong, JIANG Nan-Ping, GUO Tai-Lin, YAO Ning

2013, 34(4): 886-892. doi:10.7503/cjcu20120794

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Group A Streptococci(GAS) is an important Gram-positive human pathogen, which causes mild to severe diseases. The ability of GAS to cause infection is associated with the production of an array of secreted and cell-wall associated virulence factors. One key secreted virulence factor is a cysteine protease called streptococcal pyrogenic exotoxin B(SpeB). This protein is initially secreted as a 40000 precursor zymogen, and is subsequently cleaved to a 28000 mature form. The conversion of the zymogen form of SpeB is extremely complex and unclear. In this paper we reported a protein involved in the maturation of SpeB in the supernatant of Group A Streptococci. This protein was the streptococcus host plasminogen receptor, enolase(Eno) identified by MS/MS analysis. We constructed the eno in-deletion mutants by the method of gene knock out and investigated the correlation of enolase and maturation of SpeB in GAS. Western blot analysis and protease assays revealed a delay in the maturation of SpeB in supernatant of the eno in-deletion mutants comparing with the wild type strains. Far-Western blot analysis showed that SpeB can bind to Eno, which interact with each other. These data imply that the function of Eno, as like HtrA and RopA, is a chaperone, the regulation of protease activity and the mechanism of secretion in GAS.

Colloidal Route Preparation and Photoluminescent Properties of ZnO and ZnS/ZnO Nanoarrays on Zn Substrates

ZHUO Yu-Jiang, MEN Ying-Qian, XU Yan-Yan, SUN Wen-Dong, CHU Ying

2013, 34(4): 893-899. doi:10.7503/cjcu20120931

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Single crystal state ZnO nanorod and nanosheet arrays, as well as double-layered ZnS/ZnO composite nanorod arrays, were prepared on Zn substrates via colloidal route. X-ray diffraction(XRD), scanning electron microscopy(SEM), high-resolution transmission electron microscopy(HRTEM), and X-ray photoelectron spectroscopy were used to characterize the composition, structure and morphology of the product. The effects of reaction temperature and time on the morphology of the product were discussed and the control of surfactant on the morphology of the products in liquid phase synthesis was investigated. The luminescent properties of the synthesized nanoarray material were studied via photoluminescence technology.

Preparation of Porous Copper-based Catalysts and Their Selective Catalytic Oxidation of Benzyl Alcohol

ZHANG Gong-Shang, XING Xin-Feng, GUAN Yu, ZHOU Ai-Qiu, ZHANG Xiao-Mei

2013, 34(4): 900-905. doi:10.7503/cjcu20120900

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We fabricated porous copper(PC) by dealloying Al from Cu-Al alloy and obtained M/PC(M=Ag, Au, Pt, Pd) through galvanic replacement of Cu with noble metals using PC as reductant and template. The structural and chemical properties of the samples were characterized by X-ray diffraction(XRD) and scanning electron microscopy(SEM) with energy-dispersive X-ray spectroscopy(EDS). The catalytic performance of PC and M/PC for gas-phase selective oxidation of benzyl alcohol was investigated. PC-based M/PC catalysts showed relatively high catalytic activity in oxidation of benzyl alcohol at high temperature, among which 1% Ag/PC had the best catalytic properties.

Physical Absorption of CO₂ Using Polyvinylidene Fluoride Membrane Contactor at High Pressure and Mathematical Simulation

HUA Cong-Gui, KANG Guo-Dong, JIA Jing-Xuan, LI Meng, CAO Yi-Ming, YUAN Quan

2013, 34(4): 906-912. doi:10.7503/cjcu20120881

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The removal of CO₂ from natural gas using polyvinylidene fluoride(PVDF) hollow fiber membrane contactor was studied at high pressure. The distilled water was used as absorbent. The effects of operating pressure, inlet gas flow rate and liquid flow rate on removal efficiency of CO₂ were investigated. Based on the physical mass transfer process, the mass transfer equation of gas phase, membrane phase and liquid phase were established. The outlet CO₂ content could be predicted using Multiphysics(COMSOL) combined with 2-D mathematical model and corresponding boundary conditions. The results showed that the removal efficiency of CO₂ was affected significantly by the partial wetting of membrane. The predicted results were in good agreement with the experimental data if the wetting ratio of membrane was considered in the mathematical model.

Synthesis and Characterization of 10-Hydroxyl Camptothecin-Sebacate-LDH Nanohybrid

MA Xiu-Ming, PANG Xiu-Jiang, QUAN Zhen-Lan, HOU Wan-Guo

2013, 34(4): 913-918. doi:10.7503/cjcu20120878

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The nanohybrid of 10-hydroxyl camptothecin(HCPT)-sebacate(SC)-intercalated layered double hydroxide(LDH), HCPT-SC-LDH, was prepared by a secondary intercalation method. First, the nanohybrid of SC intercalated Mg₂Al-NO₃ LDH was prepared by a co-precipitation method; second, HCPT was intercalated into the LDH's gallery in ethanol medium. According to the gallery height of the SC-LDH sample and the size of SC molecule, a probably morphology of the SC molecules in the gallery of LDH was suggested that the SC molecules arranged as a bilayer structure in which two carboxylate groups of SC molecule combined onto one LDH layer surface. And HCPT was intercalated into the LDH's gallery via hydrophobic interaction. The encapsulated HCPT could keep biologically active lactone structure, and the nanohybrid could improve the HCPT solubility. Moreover, the obtained HCPT-SC-LDH nanocomposites showed obvious controlled release and the release in vitro of HCPT could be fitted with the pseudo-second-order model.

Different Superhydrophobic Copper Surfaces Fabricated by Wet Chemical Oxidation Method and Their Anti-condensation Property

PANG Yi-Chuan, ZHAO Ying, FENG Jie

2013, 34(4): 919-924. doi:10.7503/cjcu20120864

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Surface wet chemical oxidation is an efficient method to prepare nanostructure on copper foils toward realizing surface superhydrophobic property. However, the current studies mainly focus on the oxidation results but not on the process of oxidation reaction. Moreover, the characterization for superhydrophobicity is only by contact angle measurement. In this paper, three types of oxidants including K₂S₂O₈, (NH₄)₂S₂O₈ and ammonia were separately applied to nano roughen copper surfaces. After been treated with fluorin containing silane, all as-prepared surfaces appeared superhydrophobic property but some showed strong resistance to vapor condensation while some did not. The influence of oxidant types on the resulting morphology was compared. The nanostructure growth was believed complying with the following procedure: copper oxidation, CuO hydrolysis, Cu(OH)₂ complexation/dissolution, Cu(OH)₂ re-deposition and crystal directional growth. The vapor condensation resistances of as-prepared superhydrophobic surfaces with different nanostructures, e.g., microscopic mechanism of spontaneous motion of condensate droplets on them, were analyzed. It shows that only nanostructures with narrow space and high perpendicularity cause the obvious spontaneous motion of condensate droplets on them.

Molecular Dynamics Simulation of Carbon Nanotube Membrane Separating Li⁺/Mg²⁺

LI Hong-Man, YANG Deng-Feng, LIU Qing-Zhi, HU Yang-Dong

2013, 34(4): 925-930. doi:10.7503/cjcu20120760

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Armchair-type carbon nanotubes(CNTs) were used to construct a continuous nanotube membrane model. The conductivity behaviors of Li⁺and Mg²⁺ in the nanotubes were examined via molecular dynamics simulation. In the simulation, the permeability of Li⁺and Mg²⁺ in CNTs (7,7),(8,8),(9,9),(10,10), (11,11) with different diameters were investigated. The potentials of mean force(PMF) for ions entering the nanotubes, radial and axial ions density distributions, and the trajectories of individual ions transporting in tubes were explored. The results indicate that CNTs (9,9) is effective in separating Li⁺ and Mg²⁺ in the simulation. With different nanotube diameters, the conductance, PMF difference, trajectories, radial and axial density distributions of Li⁺and Mg²⁺ are different. In short, the carbon nanotube is a potential material for separating Li⁺and Mg²⁺.

Molecular Simulation of Interaction Mechanisms of Neuraminidase and Trihydroxy-methoxyflavone Derivatives

WU Fei, YANG Zhi-Wei, YUAN Xiao-Hui

2013, 34(4): 931-938. doi:10.7503/cjcu20120725

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A series of trihydroxy-methoxyflavone(MF) analogues was designed starting from MF, contracts that reference structural characters of the existing neuraminidase inhibitors. The docking and molecular dyna-mics simulations were carried out, aiming to discover the novel antiviral agents and contribute to the understanding on the interacting mechanisms. It is found that the binding locations of derivatives at the neuraminidase active site will not be influenced much with the addition of functional groups(carboxyl and guanidino/N-acetylamino), and there are some connections between the structures of derivatives and their interaction energies. Compound 9, with the replacements of carboxyl and guanidino groups at C7 and C5 of MF, demonstrates the highest interaction energy among the covered derivatives, equals-1172.52 kJ/mol, and is larger than the values of available lead drugs BA and MF(-672.12 and-347.44 kJ/mol). The space orientations of carboxyl and guanidino groups within the compound 9 at the neuraminidase active site are in good agreement with the current drugs. In addition, compound 9 has strong interactions with the conserved active-site residues Asp151 and Glu227, which is similar to the situation of MF. Therefore, compound 9 is a novel neuraminidase inhibitor with potential applications. We hope that these results will arouse the interest of experimental aspects to design novel anti-influenza drugs.

Self-assembly of Amphiphilic Graft Copolymer in Selective Solvent

ZHANG Jing, ZHU You-Liang, PEI Han-Wen, LIU Hong

2013, 34(4): 939-945. doi:10.7503/cjcu20120716

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The self-assembly of amphiphilic graft copolymer in different selective solvent was studied by coarse-grained molecular dynamics(CGMD) simulations. Influence of the rigidity of the backbone chain is mainly focused on. The results show that, when the solvent is good for the backbone while bad for the branches, flower micelle, flower-bridge micelle and bridge micelle can be obtained by increasing the rigidity of the backbone, when the solvent is bad for the backbone while good for the branches, core-shell structure with spherical or ellipsoidal shape, as well as the bunch structure, can be observed. Only the single core-shell structure can be obtained even for long chains in this selective solvent.

First-principles Study on NO Adsorption and Dissociation on O-Predosed Ir(100)

HE Chao-Zheng, WANG Hui, HUAI Li-Yuan, LIU Jing-Yao

2013, 34(4): 946-951. doi:10.7503/cjcu20120704

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Adsorption and dissociation of NO on O-predosed Ir(100) and the effect of co-adsorbed oxygen on the selectivity of possible products N₂, N₂O and NO₂ were investigated via first-principles density functional theory(DFT) and periodic slab model. The adsorption structures of the initial, transition and final states involved in the NO dissociation process were optimized, and the potential energy profile for each step was obtained. The results show that the most stable site for NO adsorption on O-predosed Ir(100) is the bridge site, while the top site is less stable. There are two dissociation paths for NO adsorbed on the bridge and top sites, one is direct dissociation, and the other is that NO firstly diffuses from bridge site to horizontal hollow site, followed by dissociation into N and O atoms. Similar as the decomposition mechanism on clean Ir(100), the latter is favored over the former and is the primary path for NO dissociation. The predosed O atoms inhibit the dissociation of NO at the bridge and top sites in different degrees, leading to the competition of NO dissociation on both sites. N₂ is still the predominant product, and N₂O and NO₂ are unlikely to be produced on O-predosed Ir(100), well consistent with the experimental observation. Compared with clean Ir(100), the predosed O atoms on the surface have almost no impact on the formation of N₂ at low N/O coverage, while promote the N₂ formation at high N/O coverage.

Synthesis, Crystal Structure and Quantum-chemical Calculation of Novel π-Extended Tetrathiafulvalene Derivatives

ZHU Yu-Lan, CAO Li, MA Kui-Rong, TIAN Li-Bin, WANG Xin-Long, SU Zhong-Min

2013, 34(4): 952-958. doi:10.7503/cjcu20120694

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Two novel π-extended tetrathiafulvalene derivatives, N,N'-bisbenzene-1,4-diamine(5a) and N,N'-bisbenzene-\{1,4-diamine(5b) were synthesized with p-phenylenediamine as starting material. The molecular structures were identified and characterized by ¹H NMR, mass spectrometry(MS), Fourier transform infrared(FTIR) and single-crystal X-ray diffraction(XRD). Crystal structure analysis shows that compounds 5a and 5b belong to triclinic and monoclinic system, with space group P1 and P2₁/n, respectively. The planes of the bis(imino)benzene in compounds 5a and 5b twisted from the plane of the two dithiole rings with a dihedral angle of 87.61° for compound 5a, and 43.77° for compound 5b, respectively. Moreover, the density functional theory(DFT) calculations are also carried out with Gaussian 09 program at the B3LYP/6-31+G(d,p) level to investigate the frontier orbital, electrostatic potential and spectroscopy. The experimental results are generally in good agreement with those obtained from DFT calculations.

Preparation and Capacitive Performance of the Anion Intercalation Graphite Materials as Positive Electrode Materials

LI Ran, ZHANG Hao, ZHANG Xiang-Lan, CAO Gao-Ping

2013, 34(4): 959-963. doi:10.7503/cjcu20120634

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Microstructure and energy storage performance of the needle coke heated at 1500 and 2800 ℃ were investigated by scanning electron micrograph(SEM), cyclic voltammetry(CV) and charge-discharge methods, and the influence of the degree of graphitization to the performance of graphite was studied. The specific discharge capacity of needle coke sintered at 1500 and 2800 ℃ were 70.1 and 90.6 mA·h/g in organic electrolyte when the current density was controlled at 50 mA/g. The specific capacity was 55 mA·h/g when the current density was raised to 5 A/g. However, the specific capacity of commercialization active carbon was only 35.9 mA·h/g when the current density was controlled at 50 mA/g. The retention of the capacitance after 1000 charge-discharge cycles were 95.7% and 89.2%, respectively, when the current density was controlled at 1 A/g.

Kinetics and Functional Bacteria Analysis of Dichlorophenol Degradation by Electro-biological Reduction

CAO Zhan-Ping, ZHANG Jing-Li, ZHANG Hong-Wei

2013, 34(4): 964-969. doi:10.7503/cjcu20120632

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The reductive degradation of dichlorophenol(2,4-DCP) was studied in an electro-biological system(electric-assisted microbial system). The colony structure was analyzed by polymerase chain reaction-single strand conformational polymorphism(PCR-SSCP) and a phylogenetic tree was constructed by 16S rRNA gene clone library. The results show that the dichlorophenol degradation in the electro-biological system conforms to the kinetics characteristics of zero-order reaction. Enterococcus, Pseudomonas and Bacteroidales are the dominant bacteria and play a major role in the electron transfer for the electro-biological system. The reverse electron transfer exists between the electrode, cytochrome c, NAD and the pollutants. A long-range electron transfer process of the multiphase interfaces is achieved between the electrode, bacteria and pollutants.

Thermodynamic Analysis of cBN Transformation in the Li₃N-hBN System at High Pressure and High Temperature

YANG Hong-Mei, XU Bin, GUO Xiao-Fei, WEN Zhen-Xing, FAN Xiao-Hong, TIAN Bin

2013, 34(4): 970-974. doi:10.7503/cjcu20120630

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The possibility of several reactions at high pressure and high temperature was analyzed by the determinant method of ΔG<0 in second law of thermodynamics in the process of synthesizing cubic boron nitride(BN). The ΔG of reactions Li₃N+hBNLi₃BN₂, hBNcBN and Li₃BN₂Li₃N+cBN in the Li₃N-hBN system, was calculated in considering of the change of volume with temperature and pressure, under the synthetic condition of cubic BN. It was confirmed that Li₃BN₂ was synthesized with Li₃N and hexagonal BN in certain condition of high pressure and high temperature(T>1300 K and P>3.0 GPa). When temperature and pressure raise to the area of cubic BN(T=1600—1800 K and P=4.6—6.0 GPa), it was possible for two reactions Li₃BN₂Li₃N+cBN and hBNcBN in subregion of the P-T area in thermodynamics. However, the ΔG of hBNcBN was more negative than that of the former, and it was easier for the latter reaction. A preliminary discussion about the transition mechanism of cubic BN was made with the result of calculation.

Application of Biofilm Electrode in Microbial Fuel Cell with Phenol as the Fuel

WANG Jing-Yu, HUANG Wei-Min, WANG Xuan, LIN Hai-Bo, LU Hai-Yan

2013, 34(4): 975-979. doi:10.7503/cjcu20120622

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A dual-chamber microbial fuel cell(MFC) which used phenol as the fuel, biofilm electrode as the negative electrode, Ti/SnO₂-Sb₂O₅/PbO₂ electrode as the positive electrode was set up. The biofilm electrodes were prepared by micro-current culture and natural culture methods, respectively. Effects of the microbial culture methods, biofilm formation time and substrate materials on the electricity generation ability of the MFC were investigated. The experimental results showed that the micro-current culture method was better than natural culture method, the biofilm electrodes which were prepared by micro-current culture method had higher electricity generation ability than those prepared by natural culture method. When the biofilm formation time was 8 d, the MFC had the best electricity generation ability, and its maximum power density was 39 mW/m². The order of the substrate materials of which the MFC with higher to lower electricity generation ability was carbon felt>graphite>titanium mesh>foam titanium.

Photo-electrooxidiation of I^- and Photo-assistant Rechargeable Secondary Li-ion Battery

WU Feng, XIE Xiao-Yi, ZHANG Cun-Zhong, MU Dao-Bin, WU Bo-Rong

2013, 34(4): 980-983. doi:10.7503/cjcu20120572

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The structure, micro-morphology, particle size and photo-electrochemical behavior of TiO₂ powder in I^- contained PC electrolyte were investigated by XRD, SEM and micro-cavity electrode. The results indicate that the size of used TiO₂ sample is from 100 nm to 200 nm. The results indicate that the potential of oxidation of I^- on anatase-TiO₂ is 1 V at irradiation condition, lower than that of oxidation of I^- at dark condition. Furthermore, a type of photo-assistant rechargeable Li-ion battery was composed by anatase-TiO₂/ITO semi-conductor photo-anode, poly(vinylidene fluoride)(PVDF) membrane and Li₄Ti₅O₁₂ negative electrode. The charging voltage of such battery is 0.9 V at irradiation condition lower than that of the battery at dark condition. The results of UV-Vis spectroscopy indicate that the charging product of anode half-cell is I₂. At the same time, the Li-ion insertion reaction happens on Li₄Ti₅O₁₂ negative electrode. The total photo-assistant charging reaction of battery is listed as follows: 3LiI+Li₄Ti₅O₁₂+3hν(3/2)I₂+Li₇Ti₅O₁₂. The results suggest that such batteries can be used as model for the development of next generation photo-assistant rechargeable Li-ion battery.

Preparation of Controlled-release PLA Microspheres Loading Methylsulfonylmethane and Its Biological Activity

WANG Xin-Zhong, LIU Jian-Guo, TANG Yu-Feng, WANG Yu, ZHANG Pei-Biao, CHEN Xue-Si

2013, 34(4): 984-991. doi:10.7503/cjcu20121108

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Polylactic acid(PLA) microspheres carrying methylsulfonylmethane(MSM) were prepared by membrane emulsification. The effects of membrane pore size, stirring speed and MSM concentration on microspheres morphology, size, drug loading and in vitro release, as well as cell biological activity were studied using environmental scanning electron microscope(ESEM), inductively coupled plasma atomic emission spectrometer(ICP-AES), in vitro culture of MC3T3-E1 cell and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenylte-trazolium bromide(MTT) method. The study will provide references for the study of the long-acting release agent of MSM. The results showed that the drug-loaded microspheres prepared with membrane emulsification were typical spherical with smooth surface and the internal porous structure. The size and morphology of the microspheres could be affected by membrane pore size, stirring speed and MSM concentration. The drug-loaded microspheres prepared with the membrane pore size of 5.1 μm and a stirring speed of 500 r/min were more uniform in size than others. When the mass fraction of MSM solution was 8.6%, the drug loading of microspheres could be up to 77.43%. The in vitro release rate of MSM could be sped up when the membrane pore size was reduced and the MSM concentration was increased, but the initial burst release for all samples was not obvious, and it reached up to 89.2% after 10 d. The cell experiments showed that cell proliferation of MC3T3-E1 was improved at 7 d cell culture using MSM-loaded microspheres with the membrane pore size of 5.1 μm and MSM mass fraction of 8.6%. The research indicates that the PLA/MSM drug-loaded microspheres has good controlled release characteristics and biological activity, which can be used as a long-acting release formulation of MSM for the treatment of osteoarthritis and application in bone and cartilage tissue engineering.

One Step Synthesis of Porous Polyurea and Its Application to Dye Adsorption in Water

LI Shu-Sheng, JIANG Xu-Bao, KONG Xiang-Zheng

2013, 34(4): 992-999. doi:10.7503/cjcu20121003

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A novel one-step protocol for facile preparation of porous polyurea material(PPU) through precipitation step polymerization of toluene diisocynate(TDI) as the sole monomer with water in water-acetone mixed solvent was presented, in which neither any porogen during the polymerization, nor chemical modification on the outcome polymer was need. The surface morphology and pore parameters of PPU as prepared were characterized by scanning electron microscope(SEM) and Brunauer-Emmett-Teller(BET) nitrogen adsorption, respectively. Presence of abundant amine groups on PPU surface was confirmed by infrared measurement. Using acid fuchsine(AF) in aqueous solution as an example for dyes in wastewaters, the effects of AF adsorption pH, adsorption time, AF concentration and amount of PPU on the adsorption process were studied. AF adsorption was more effective with pH located between 2—4; adsorption equilibrium was usually reached with 4 h. AF was nearly full adsorbed at low concentration or with high PPU loading. The maximum adsorption capacity of AF on PPU was 44.60 mg/g under optimized conditions. Analysis of the adsorption results demonstrated that the adsorption was better fit by Langmuir adsorption equation compared to Freundlich adsorption. In addition, Congo red(CR) was also used and its adsorption on PPU also studied. The maximal adsorption of CR on PPU was of 90.48 mg/g. Desorption test demonstrated that over 92% of the adsorbed dye molecules on PPU were desorbed when PPU with adsorbed dyes was immersed into NaOH solution(1 mol/L) or H₂O/ethanol mixture(1: 1, volume ratio) for 2 h. The following reuse of PPU demonstrated that dye adsorption was higher than 90% of the initial adsorption in the re-adsorption, and it was higher than 80% of the initial adsorption in the third adsorption. The results indicate that PPU is an effective absorbent to remove AF and CR in aqueous medium, and an attractive candidate for removal of anionic dyes from the wastewaters.

Adsorption Character of Polyvinyl Alcohol-grafted Particles for Flavonoids by Driving of Hydrogen Bond Interaction

ZHANG Yan-Yan, GAO Bao-Jiao, MEN Ji-Ying

2013, 34(4): 1000-1006. doi:10.7503/cjcu20120841

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The adsorption characters of two kinds of flavonoids, quercetin and rutin, were conducted by polyvinyl alcohol(PVA)-grafted silica gel particles PVA/SiO₂ as solid adsorbent. The research results show that the conventional hydrogen bond with multiple sites and π type hydrogen bond can be formed between the hydroxyl groups with high density on the surfaces of the functional composite particles PVA/SiO₂ and the hydroxyl groups and the conjugated aromatic rings in the molecules of flavonoid compounds. The competing adsorption of the solvent will produce great negative effects on the adsorption capacity of the flavonoids. In 1,2-dichloroethane(DCE) as a weak polarity solvent, the competing adsorption of the solvent barely exists. Therefore, when DCE is used as solvent, quercetin and rutin have very high adsorption capacities, and they are 0.32 mmol/g(96 mg/g) and 0.23 mmol/g(140 mg/g), respectively. While in ethanol as a protic solvent, the adsorption capacities of quercetin and rutin decline greatly as a result of the strong competing adsorption of the solvent, and they are 0.22 mmol/g(65 mg/g) and 0.14 mmol/g(87 mg/g), respectively. Rising temperature will weaken the hydrogen bond interaction between the functional composite particles PVA/SiO₂ and quercetin or rutin, and even makes the hydrogen bond rupture, leading to the decrease of the adsorption capacity. The existence of electrolytes in the protic solvent will influence the adsorption negatively. The adsorption process of the functional composite particles PVA/SiO₂ for flavonoids is exothermic and driven by enthalpy.

Preparation and Film Properties of SiO₂@P(MMA/BA/3FMA) Composite Nanoparticles

PAN Ai-Zhao, HE Ling, ZHANG Wen-Wei

2013, 34(4): 1007-1013. doi:10.7503/cjcu20120829

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Nano-SiO₂@P(MMA/BA/3FMA) core-shell composite nanoparticles were synthesized by emulsion polymerization with the modified nano-SiO₂ from tetraethyl orthosilicate(TEOS) hydrolysis as the core and the fluorinated copolymer of methyl methacrylate(MMA), n-butyl acrylate(BA) and 2,2,2-trifluoroethyl methacrylate(3FMA) as the shell. In order to overcome the agglomeration of nano-SiO₂ particles and to improve the chemical integration to the shell copolymer, vinyltrimethoxysilane(VTMS) was used as the surface modifier for nano-SiO₂ particles. Fourier transforms infrared spectroscopy(FTIR), transmission electron microscope(TEM), dynamic light scattering(DLS), static contact angles(SCA), X-ray photoelectron spectroscopy(XPS) and thermogravimetric analysis(TGA) were employed to characterize the structures of the composite nano-particles and the film properties. The results indicated that SiO₂@P(MMA/BA/3FMA) composite presented the uniform spherical core-shell partials with 40—50 nm in diameter. 25%(Mass fraction) 3FMA gave the lowest surface energy due to the migration of fluorine to the surface during the film formation. The thermal behavior of SiO₂@P(MMA/BA/3FMA) was improved with the increase of 3FMA content.

Synthesis, Characterization and Micellization of Star-shaped Amphiphilic Block Copolymer 6-s-PLGA_x-PEG-NH₂

CHEN Yong-Xia, YANG Zi-Ying, WANG Liang, ZHANG Zheng-Pu, KONG De-Ling, YANG Jing, SUN Hong-Fan, SONG Cun-Xian

2013, 34(4): 1014-1020. doi:10.7503/cjcu20120730

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The star-shaped poly(lactide-co-glycolide)(PLGA) was synthesized via the ring-opening polymerization of D,L-lactide and glycolide, with inositol as a multifunctional initiator and stannous 2-ethylhexanoate as a catalyst. Amine-terminated poly(ethylene glycol)(NH₂-PEG-NH₂) was synthesized using improved Gabriel method, in which the end hydroxyl groups were converted to amino groups. A series of 6-s-PLGA_x-PEG-NH₂ was prepared using classical DCC condensation reaction in the mild condition. The structures of these polymers were characterized by ¹H NMR spectroscopy, while the molecular weight and polydispersity index(PDI) were determined by gel permeation chromatography(GPC). The glass transition temperature(T_g) of copolymer was determined by differential scanning calorimetry(DSC). The NH₂-PEG-NH₂ was characterized using IR and element analyses, the result of element analysis proved that the hydroxyl conversion was up to 90%. Nanoparticles(NPs) were prepared by solvent evaporation method, ¹H NMR was used to analysis the structure of the NPs, dynamic light scatering(DLS) for the size and size distribution, transition electron microscope(TEM) for the morphology of the NPs. The biocompatibility was detected with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltertrazolium bromide(MTT) assay. The results showed success of synthesis of star-shaped amphiphilic block copolymer 6-PLGA_x-PEG-NH₂. The new polymer has good biocompatibility and can formulate micelles easily. It may be used as a new drug carrier for drug controlled system.

Surface Acetylation of Cellulose Nanowhiskers and Its Reinforcing Function in Cellulose Acetate

YANG Zhen-Yu, WANG Wen-Jun, SHAO Zi-Qiang, LI Yong-Hong

2013, 34(4): 1021-1026. doi:10.7503/cjcu20120691

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Cellulose nanowhiskers were prepared by sulfuric acid hydrolysis, then they were chemically modified by acetylation to obtain acetylated cellulose nanowhiskers(ACNW). The chemical and morphology structure of the ACNW were examined with Fourier transform infrared spectroscopy(FTIR), X-ray diffraction(XRD), transmission electron microscopy(TEM) and X-ray photoelectron spectroscopy(XPS). ACNW with too low or too high degree substitute(DS) were not suitable for fillers in nanocomposites. When the DS of ACNW was 0.05, the acetylation modification limited only on the surface of the cellulose nanowhiskers, and the modified cellulose nanowhiskers preserved their original rod-like structure and high degree of crystallization. Cellulose acetate(CA) nanocomposites were prepared using ACNW as fillers by a casting/evaporation technique, and the effect of ACNW contents on the tensile properties of the CA matrix was studied. The tensile strength, Young's modulus, and strain at break of all CA nanocomposites exhibited simultaneous increase in comparison with neat CA matrix. The storage modulus of CA nanocomposites after temperature of glass transition(T_g) was higher than the neat CA matrix.

Characterization and Molecular Simulation of HNBR with Different Hydrogenation Degree

WU Si-Zhu, HU Tao, ZHOU Hao, GAO Yue-Kai, YUE Dong-Mei

2013, 34(4): 1027-1032. doi:10.7503/cjcu20120591

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By combining hydrogen nuclear magnetic resonance(¹H NMR), infrared(IR) spectroscopy and thermal analysis, the microstructures of hydrogenated nitrile rubber(HNBR) with different hydrogenation degree(HD) were investigated. The result indicated that the rates of hydrogenation reactions of different functional groups were different in the sequence of the highest rate of vinyl group in polybutadiene, the second rate of trans-1,4-unit group and the lowest rate of cis-1,4-unit group. The nitrile groups were almost stable during the hydrogenation process. By ¹H NMR experiment, the contents of various groups in HNBR with different HD were quantitatively analyzed. These results were introduced to construct proper polymer chains in molecular dynamics simulation(MD) which contributed to calculate various parameters such as density, cohesion energy density(CED), and glass-transition temperature(T_g), etc, agreed well with experimental results. The results showed that the improvement of thermal stability of HNBR with the increase of HD was due to the decrease of double bonds content and increase of CED. The good agreement between experimental and theoretical simulation results indicated that the MD can effectively calculate the structure parameters, provided fundamental data and theoretical direction for the preparation and processing of copolymerized rubber materials.

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