Fluorescence behavior of porphinato zinc derivative in the molecular assembly of polymerized lipid

Summary 3,8,13,17-Tetramethyl-7,12-dicarboxy-2,18-bis(octadecyloxycarbonylethyl) porphinato zinc (DCPZn) was incorporated into bilayer membrane of liposomes of 1,2-bis(2,4-octadecadienoyl)sn-glycero-3-phosphocholine (DODPC). The liposomes were polymerized by initiators like water-insoluble azobisisobutyronitrile (AIBN) or/and water-soluble azobis(amidinopropane) dihydrochloride (AAPD). DCPZn does not disturb the molecular packing of DODPC in the bilayer and after the polymerization, DCPZn is fixed monomolecularly in the network of the crosslinked bilayer membrane, while in the monomeric bilayers the dispersion state of DCPZn depends on temperature and concentration.This work was partially supported by a Grand-in Aid from the Ministry of Education, Science and Culture, Japan.     

Watersoluble polymers in medicine

Different polymeric transport systems for biologically active substances are presented. In the past, most of the reviews on polymeric drugs dealt with pharmaca, fixed to conventional water-soluble polymers. Naturally occuring transport proteins with their complex features have recently been imitated by micellar solubilized polymers. Polymerized liposomes from polymerizable lipids can be regarded as vesicular solubilized polymers and are discussed as stable models for biomembranes. By insertion of glycolipids, these liposomes are rendered susceptible to specific recognition by proteins. When natural or cleavable synthetic lipids are incorporated into polymerizable membranes, phase-separation of the different lipid fractions may occur. The unpolymerized components can then be degraded or solubilized and thereby can be removed from the polymerized matrix, allowing a selective opening of stable compartments.     

Preparation and characterisation of novel phospholipid cationic liposomes to improve the alkaline hydrolysis and dyeability of polyester fabric

Three novel cationic liposomes were prepared from commercial soybean lecithin (neutral liposome) and stearylamine (cationic liposome) as a catalyst or accelerating agent for the alkaline hydrolysis of polyester fabric. The formation of 1:1, 1:6 and 1:12 cationic liposomes was confirmed by transmission electron microscopy, nitrogen content and Fourier Transform‐infrared spectroscopy. Factors affecting the alkaline hydrolysis performance of polyester fabric in the presence and absence of cationic liposomes were investigated. Size measurements of the three cationic liposomes showed that the vesicle size was 27.88 nm for the 1:1 cationic liposome, 15.57 nm for 1:6 and 10 nm for 1:12, in comparison with 50 nm for neutral liposome. The results showed that alkaline hydrolysis in the presence of cationic liposomes improves the hydrophilicity and dyeability of polyester fabric and creates more carboxylic groups on the fabric. The silky polyester fabric was characterised by scanning electron microscopy, tensile strength, elongation at break, crease recovery angle and surface roughness to prove the success of the cationic liposomes as accelerating agents in the alkaline hydrolysis process. The results also indicate that the colour strength of hydrolysed polyester fabric in the presence of cationic liposomes dyed with disperse dye was slightly higher than that obtained in the absence of cationic liposomes and with unhydrolysed fabric. Furthermore, the fastness properties of hydrolysed polyester in the absence and presence of cationic liposomes do not vary.     

Development and Characterization of DOPEPEG2000 Coated Oleic Acid Liposomes Encapsulating Anticancer Drugs

Liposomes have been widely investigated as drug carriers for a broad range of anticancer drugs. However, their application as a drug delivery system may be challenging due to low encapsulation of active ingredient and poor stability which leads to uncontrolled delivery of bioactive ingredients. The present study aims at incorporating 1,2‐dioleoyl‐sn‐glycero‐3‐phosphoethanolamide‐N‐[methoxy(polyethylene glycol)‐2000 (DOPEPEG2000) into oleic acid (OA) liposomes in order to prolong the lifetime in blood circulation. The pH transition curve of oleic was obtained by titration of sodium oleate solution with 0.05 mol dm^?3 HCl to determine the region where liposomes were abundantly present. The critical vesicle concentration (CVC) was then determined by surface tension measurements. Dry lipid liposomes were hydrated with phosphate buffer at just over twice the CVC value. Optical polarizing microscopy (OPM) showed the presence of liposomes while transmission electron microscopy (TEM) confirmed that the liposomes prepared were spherical in shape and less than 200 nm in size. The incorporation of DOPEPEG2000 into the oleic acid liposomes reduced the average particle size and zeta potential to mimic the red blood cells. The encapsulation efficiency of various anticancer drugs was more than 60% while more than 20% of the drugs were released after 24 h. The results suggest that DOPEPEG2000: oleic acid at a molar ratio of 1:50 fulfilled the requirements for intravenous drug delivery.     

多囊泡型二氢杨梅素脂质体的制备、表征及其抑菌性能

耐药金色葡萄球菌的出现和高效抗生素的缺乏已经对食品质量与公共安全造成威胁,因此,亟需寻找一种新的治疗策略来应对日益严峻的细菌挑战。本研究采用水热提取法从藤茶提取二氢杨梅素（DMY）,并以脂质体为药物载体、聚乙二醇4000为修饰剂成功制备出多囊泡型二氢杨梅素脂质体（DMY-lips）。使用紫外分光光度计、傅里叶红外光谱仪、X射线粉末衍射仪和同步热分析仪分析确定了DMY的成功包覆,并通过透射电子显微镜和纳米粒度测试仪证实了脂质体的多囊泡结构。该脂质体粒径均一,平均粒径为155 nm,载药率为42.93%。此外,抑菌实验证实脂质体的包覆提高了DMY的抑菌活性和抑菌时间,这主要是由于脂质体提高了DMY的水解度和膜渗透度。DMY-lips对金色葡萄球菌的最小抑菌浓度为0.05 mg/ml。生物扫描电镜和电导率测试实验表明DMY-lips可以破坏金色葡萄球菌的细胞壁和细胞膜,导致菌体膜内内容物流出而死亡。因此,该多囊泡型二氢杨梅素脂质体在制药行业具有巨大潜力,并有望缓解医疗系统对化学抗生素的依赖。     

Dendritic polychelatogens: Synthesis,characterization, and metal ion binding properties

Rigid monoliths were prepared from concentrated oil in water (O/W) emulsions by a base-catalyzed polycondensation reaction of 2-nitroresorcinol with cyanuric chloride. Mercury intrusion/extrusion porosimetry confirmed that the obtained monoliths were porous with an open porosity. However, scanning electron microscopy showed that the structure of these materials was different from that of emulsion-derived materials previously described in the literature [polymerized high internal phase emulsions (polyHIPEs)]. In comparison with polystyrene/divinylbenzene-based polyHIPEs obtained by radical polymerization, these materials exhibited a higher skeletal density, and thermogravimetric analysis and differential scanning calorimetry analysis indicated that they were more thermally stable. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

自聚甲基丙烯酸甲酯的结构及性能

通过核磁共振波谱、热失重分析仪、差示扫描量热仪及凝胶渗透色谱研究了自聚甲基丙烯酸甲酯(PMMA)的分子链结构、热稳定性、相对分子质量及其分布,并对PMMA的自引发聚合机理进行了探讨。结果表明,与引发剂引发合成PMMA相比,自聚PMMA的相对分子质量更高,分布更宽;自聚PMMA分子链内均含有热不稳定的过氧键,致使其在130 ℃便开始降解,但它对PMMA的热稳定性没有影响;自聚合是由氧与甲基丙烯酸甲酯单体（MMA）反应形成低相对分子质量过氧化物引发的。     

Improvement of Interfacial Adhesion of Glass Fiber/Epoxy Composite by Using Plasma Polymerized Glass Fibers

This study intends to produce plasma polymer thin films of γ-glycidoxypropyltrimethoxysilane (γ-GPS) on glass fibers in order to improve interfacial adhesion of glass fiber-reinforced epoxy composites. A low frequency (LF) plasma generator was used for the plasma polymerization of γ-GPS on the surface of glass fibers at different plasma powers and exposure times. X-ray photoelectron spectroscopy (XPS) and SEM analyses of plasma polymerized glass fibers were conducted to obtain some information about surface properties of glass fibers. Interlaminar shear strength (ILSS) values and interfacial shear strength (IFSS) of composites reinforced with plasma polymerized glass fiber were evaluated. The ILSS and IFSS values of non-plasma polymerized glass fiber-reinforced epoxy composite were increased 110 and 53%, respectively, after plasma polymerization of γ-GPS at a plasma power of 60 W for 30 min. The improvement of interfacial adhesion was also confirmed by SEM observations of fractured surface of the composites.     

从糖精废水中提取金属铜及废水综合利用

利用废铁卷与含铜酸性废水作用制备金属铜和聚合硫酸铁,并用聚合硫酸铁作絮凝剂处理酯化废水. 实验结果表明,1 t含铜酸性废水可制得8.5 kg铜粉及230 kg Fe3+浓度为158~160 g/L的聚合硫酸铁,处理后酸性废水中的硫酸含量降低了83.5%, Cu2+含量降低了85.0%. 在优化条件下,沉降30 min,酯化废水的COD及色度去除率分别达到了86.8%和88.5%.     

双取代聚乙炔衍生物的合成与光学性能研究

用WCl6-Ph4Sn催化下聚合生成了双取代乙炔衍生物,在产物的红外光谱上,2 205 cm-1处C-C键的伸缩振动特征吸收峰消失及1 621 cm-1处C=C双键的生成,这些特征变化证明了聚合反应的发生。单体苯丙炔酸通过肉桂酸的加成消去反应制得,单体C6H5C-CCOO(C6H4)OCOCH2CH3则通过苯丙炔酸和对羟基苯甲酸乙酯酯化制得,通过红外光谱、元素分析、XRD、紫外光谱和荧光光谱对聚合物结构和性质进行了表征,结果显示,这种共轭聚合物在光激发下能发出蓝光且聚合物能溶于普通的有机溶剂。     

Synthesis and application of methoxy poly(ethylene glycol)‐bile salts conjugates in physicochemical characterization and the pharmacokinetics of the liposomal bifendate in rats

Stealth liposomes have been broadly investigated as drug delivery or diagnostic agent. However, the materials that possess the ability of stealth, such as DSPE‐PEG and Chol‐PEG, are either costly or synthetic complex. In this research with different molecular weights (2000–6000 g/mol) of methoxy poly(ethylene glycol)(MePEG), a series of MePEG‐bile (MePB) conjugates were generated by an economical and simple method and confirmed by FTIR and ¹H‐NMR spectrum. The properties in aqueous solution were studied, including viscosity and surface activity, over a wide concentration range. To elucidate the application of MePB in liposomes (MePBL), conventional liposomes (CL) were prepared, and the influence of the grafting density and the chain length of MePB in liposomes were investigated. The ability of long circulation of MePBL was evaluated by intravenous injection administration in rats. Results indicated that all the liposomes prepared, with or without MePB composition, were similar in micrograph, and the contents of MePB in MePBL were more important than the chain length of MePB for a long circulation in vivo. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Chemospecific ring-opening polymerization of α-methylenemacrolides

α-Methylenemacrolides having various groups, such as aromatic, ether, and amine, were enzymatically, anionically, and radically polymerized. The polymerization with the lipase catalyst successfully afforded polymers only through the ring-opening process, whereas the vinyl polymerizations selectively proceeded by using anionic and radical initiators. The polyesters obtained by the enzymatic polymerization have a polymerizable methacrylic methylene group in the main-chain, in addition to the aromatic and polar groups, and were further radically polymerized to quantitatively produce a cross-linked polymer gel.     

Effect of cation structure on the electrochemical and thermal properties of ion conductive polymers obtained from polymerizable ionic liquids

Several onium cations having vinyl group formed ionic liquids after coupling with bis(trifluoromethanesulfonyl)imide. These monomers were polymerized, and the relation between onium cation structure and properties of thus polymerized ionic liquids was investigated. The polymerized ionic liquid having ethylimiadzolium cation unit showed the highest ionic conductivity of around 10⁻⁴ S cm⁻¹ at 30 °C among the obtained polymers reflecting the lowest glass transition temperature of −59 °C. These polymers were thermally stable and their decomposition temperatures were about 350 °C. The ionic conductivity of the polymerized ionic liquids decreased by both the addition of lithium bis(trifluoromethanesulfonyl)imide and the polymerization in the presence of cross-linker. However, the polymerized ionic liquid having 1-methylpiperidinium cation structure showed good lithium ion transference number of 0.43 at room temperature.     

Cysteine-Encapsulated Liposome for Investigating Biomolecular Interactions at Lipid Membranes

The development of a strategy to investigate interfacial phenomena at lipid membranes is practically useful because most essential biomolecular interactions occur at cell membranes. In this study, a colorimetric method based on cysteine-encapsulated liposomes was examined using gold nanoparticles as a probe to provide a platform to report an enzymatic activity at lipid membranes. The cysteine-encapsulated liposomes were prepared with varying ratios of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and cholesterol through the hydration of lipid films and extrusions in the presence of cysteine. The size, composition, and stability of resulting liposomes were analyzed by scanning electron microscopy (SEM), dynamic light scattering (DLS), nuclear magnetic resonance (NMR) spectroscopy, and UV-vis spectrophotometry. The results showed that the increased cholesterol content improved the stability of liposomes, and the liposomes were formulated with 60 mol % cholesterol for the subsequent experiments. Triton X-100 was tested to disrupt the lipid membranes to release the encapsulated cysteine from the liposomes. Cysteine can induce the aggregation of gold nanoparticles accompanying a color change, and the colorimetric response of gold nanoparticles to the released cysteine was investigated in various media. Except in buffer solutions at around pH 5, the cysteine-encapsulated liposomes showed the color change of gold nanoparticles only after being incubated with Triton X-100. Finally, the cysteine-encapsulated liposomal platform was tested to report the enzymatic activity of phospholipase A₂ that hydrolyzes phospholipids in the membrane. The hydrolysis of phospholipids triggered the release of cysteine from the liposomes, and the released cysteine was successfully detected by monitoring the distinct red-to-blue color change of gold nanoparticles. The presence of phospholipase A₂ was also confirmed by the appearance of a peak around 690 nm in the UV-vis spectra, which is caused by the cysteine-induced aggregation of gold nanoparticles. The results demonstrated that the cysteine-encapsulated liposome has the potential to be used to investigate biological interactions occurring at lipid membranes.     

Phase separation of polymerized lipids in hybrid liposomes

Summary Hybrid liposomes were prepared from the mixture of dipalmitoyl phosphatidylcholine (DPPC) and di-2,4-octadecadiene phosphatidylcholine (DODPC), and their phase separation behaviours was analyzed. In hybrid liposome systems, two transition temperatures (18 and 41°C for DODPC and DPPC, respectively) were clearly observed by means of DSC and fluorescence techniques. These two transition temperatures were also found after polymerization of DODPC molecules in hybrid liposomes by the UV irradiation. These strongly suggest that DPPC and DODPC molecules do not dissolve well but form clusters in the membrane. This phase separation was directly confirmed by freeze-fracture TEM technique.     

Synthesis and Spectral Characterization of Cross Linked Rigid Structured Schiff Base Polymers: Effect of Substituent Position Changes on Optical,Electrical, and Thermal Properties

Three Schiff base diol monomers were oxidatively polymerized with NaOCl as an oxidant. The structures of the monomers and polymers were confirmed by various spectroscopic techniques. Conductivity of the iodine doped polymers measured was compared based on the total charges on imine nitrogen calculated by Huckel method. The polymers were having quite lower band gap than the monomers. Fluorescence spectra of monomers and polymers showed that the excitation and emission maxima centered in the region 362–400 nm and 467–513 nm with large stokes shift. High carbine residue, around 50% at 800°C confirmed that the polymers were having good thermal stability.     

国产溶聚丁苯橡胶T2000R的基本配合性能

根据丁苯橡胶的基础配方,考察了国产溶聚丁苯橡胶( SSBR)(牌号为T2000 R)的基本配合性能,并与乳聚丁苯橡胶(ESBR)(牌号为1502)进行了时比.结果表明,对于SSBR,普通硫黄体系下硫化胶具有较高的撕裂强度和耐屈挠疲劳性能,而半有效硫黄体系下硫化胶的耐磨耗性能和耐压缩疲劳性能最优,相同硫化体系下,SSBR...     

Egg phosphatidylcholine and dioleoylphosphatidylethanolamine liposomes containing acid proteinoid: Comparison of pH‐sensitivity

pH‐Sensitive liposomes were prepared by modifying the surfaces of egg phosphatidylcholine (EPC) liposomes and dioleoylphosphatidylethanolamine (DOPE) liposomes with an acidic proteinoid. The acidic proteinoid (Prot AL) was prepared by a melt‐condensation of aspartic acid and leucine (98.5:1.5 mol/mol). The maximum amount of Prot AL accommodated by EPC liposomes without loss of the fluorescence quenching of calcein occurred when the ratio of Prot AL to EPC was 1:2. The EPC liposomes exhibited pH‐dependent release but the degree of release in 5 min was less than 10% in the range of pH 6.0–8.0. A marked increase in release was observed at pH 5.5 and the degree of release was about 38%. Acidification‐induced contraction of Prot AL may impose a mechanical stress on the liposomal membrane, deforming and demaging the membrane. On the other hand, a high fluorescence quenching, more than 60%, was obtained when the ratio of Prot AL to DOPE was 5.5:10. The pH‐sensitivity of DOPE liposomes bearing the proteinoid was much higher than that of egg PC liposomes bearing the same proteinoid. Following the changes in the size with varying pH, DOPE liposomes seemed to be disintegrated.     

Liposomes of phosphatidylcholine: a biological natural surfactant as a dispersing agent

Disperse dyes are very hydrophobic molecules that in their commercial form are usually milled in the presence of large amounts of dispersing agents (synthetic surfactants). Other dispersing agents are added as auxiliaries during the dyeing process. These synthetic surfactants were substituted for liposomes prepared with phosphatidylcholine, a well-known biological surfactant of natural origin which is environmentally friendly, and liposomes were studied as a dispersing agent in polyester dyeing.
The physicochemical behaviour of dye dispersion was analysed by two experimental measurements: the aggregation process of dye particles by filtration of dispersion and the determination of the turbidity ratio. The results obtained show the usefulness of liposomes as a dispersing auxiliary in a dyeing process, avoiding aggregation of dye molecules at high temperatures. Moreover, polyester dyeing shows similar final exhaustions, approximately 90%, at different kinetics, when liposomes are used.     

手性聚苯胺改性硅藻土复合材料的制备

在樟脑磺酸的手性诱导作用下,在硅藻土表面原位聚合苯胺得到手性聚苯胺改性硅藻土复合材料,利用红外吸收光谱(FTIR)和扫描电子显微镜(SEM)对复合材料的结构进行表征,表明苯胺在硅藻土表面进行了原位聚合,聚合产物呈现纳米棒状态。通过测试复合材料的循环伏安特性曲线(CV)表征材料的电化学性能,对比了在不同手性聚苯胺/硅藻土配比以及不同时间条件下改性材料的性能差异。结果表明:随着苯胺聚合量的增大以及反应时间的增加,复合材料的电化学性能会呈现先增大后减小的趋势。