Chemometrics-assisted spectrophotometric methods for simultaneous determination and complexation study of Fe(III), Al(III) and V(V) with morin in micellar media

Evolutionary factor analysis (EFA) and rank annihilation factor analysis (RAFA) were applied to resolve the two-way equilibrium spectrophotometric data belonging to the complexes of Fe(III), Al(III) and V(V) with morin (3,5,7,20,40-penta hydroxy flavone) as chelating agent in triton X-100 micellar media. Then, partial least square regression combined with genetic algorithm for wavelength selection (GA-PLS) was used for simultaneous determination of the metal ions. The parameters controlling behavior of the system were investigated and optimum conditions were selected. The predictive abilities of partial least squares regression (PLS) and genetic algorithm-partial least squares regression (GA-PLS) were examined in simultaneous determination of ternary mixtures of metal ions over the concentration range of 17.0-170.0ngml(-1), 25.0-180.0ngml(-1) and 40.0-325.0ngml(-1) for Fe(III), Al(III) and V(V), respectively. The relative standard errors for prediction of the ions in synthetic mixtures were lower than 5% and the mean recoveries in the tap water spiked samples were 104.2 and 101.7% for PLS and GA-PLS, respectively.     

Resorcinarene-centered Amphiphilic Star-block Copolymers: Synthesis,Micellization and Controlled Drug Release

Eight-arm star-shaped poly（■-caprolactone）-block-poly（ethylene glycol）s（SPCL-b-PEG） have been prepared by a combination of controlled ring-opening polymerization（CROP） and coupling reaction. First, eight-arm star-shaped poly（■-caprolactone）s（SPCL） with a resorcinarene core were synthesized using octamethyl tetraundecylresorcinarene octaacetate as octa-initiator and yttrium tris（2,6-di-tert-butyl-4-methylphenolate） [Y（DBMP）3] as catalyst. Then the coupling reaction was carried out between SPCLs and carboxyl-terminated methoxy poly（ethylene glycol）s（mP EG-COOH） in the presence of N,N′-dicyclohexylcarbodiimide（DCC） and 4-dimethylaminopyridine（DMAP）, resulting in eight-arm star-shaped SPCL-b-PEGs with controlled molecular weight and well-defined architecture. Furthermore, these amphiphilic eight-arm SPCL-b-PEGs could self-assemble into micelles with low critical micellar concentrations（CMC）, which was characterized by fluorescent spectroscopy. Moreover, indomethacin loaded micelles with high drug loading content and high encapsulation efficiency can be prepared, which is probably due to the highly branched architecture. The morphologies of micelles were characterized by transmission electron microscopy（TEM）, which exhibited diverse nanostructures as the drug loading contents varied. In vitro drug release of indomethacin from SPCL-b-PEG micelles was carried out in PBS, from which a sustained release behavior was observed. SPCL-b-PEG micelles did not show significant cytotoxicity at copolymer concentrations up to 1000 mg/L, making them very promising for drug delivery.     

反应性嵌段共聚物自组装制备无机纳米粒子研究进展

具有"核-壳"结构的嵌段共聚物胶束具有广泛的用途.本文介绍了反应性嵌段共聚物的自组装技术应用于制备具有独特的光、电、磁等以及催化特性的无机纳米粒子,特别是介绍了近年来在制备纳米贵金属粒子的研究进展.     

The synthesis of biodegradable graft copolymer cellulose-graft-poly(L-lactide) and the study of its controlled drug release

According to the concept of green chemistry and sustainable development, a new biodegradable copolymer comprised of hydrophobic poly(l-lactide) (PLLA) segments and hydrophilic cellulose segment (cellulose-g-PLLA) was designed and synthesized. The structure of the copolymer was characterized by (1)H NMR, FT-IR, (13)C NMR, DSC and WAXD. The cytotoxicity study shows that cellulose-g-PLLA exhibits good biocompatibility. The copolymer can self-assemble into micelles in water with the hydrophobic PLLA segments at the cores of micelles and the hydrophilic cellulose segments as the outer shells. Transmission electron microscopy (TEM) shows that the micelles exhibit nanospheric morphology within a size range of 30-80nm. The drug loaded micelles formed by the copolymer in aqueous media show sustained drug release which indicates their potential applicability in drug carrier.     

Biodegradable and thermoresponsive micelles of triblock copolymers based on 2-(N,N-dimethylamino)ethyl methacrylate and ε-caprolactone for controlled drug delivery

Amphiphilic triblock copolymers, poly(2-(N,N-dimethylamino)ethyl methacrylate)_x-block-poly(caprolactone)-block-poly(2-(N,N-dimethylamino)ethyl methacrylate)_x, PDMAEMA_Co, were synthesized. Polymerization and structural features of the polymers were analyzed by different physicochemical techniques (GPC, ¹H NMR and FTIR). Formation of hydrophobic domains as cores of the micelles was studied by ¹H NMR and further confirmed by fluorescence. Dynamic light scattering measurements showed a monodispersed size distribution only for the copolymer with the lowest degree of polymerization, while increasing the length of PDMAEMA blocks leads to a bimodal size distribution. The micelles showed reversible dispersion/aggregation in response to temperature cycles through an outer polymer shell lower critical solution temperature (LCST) for PDMAEMA at temperatures between 54 and 87 °C. The triblock copolymer micelles were loaded with the sparingly water-soluble anticancer drug, chlorambucil, by a dialysis procedure. The drug release profile monitored by fluorescence showed that the release of chlorambucil from PDMAEMA nanoparticles is controlled by a combined degradation-diffusion mechanism.     

一种两亲性嵌段共聚物胶束的制备及其对叶酸的负载和控制释放

采用可逆加成-断裂链转移(RAFT)聚合合成了以丙烯酸异丁酯(IBA)、甲基丙烯酸2-二甲氨乙酯(DMAEMA)无规共聚嵌段与聚丙烯酸-2-羟丙酯(PHPA)组成的两亲性两嵌段共聚物(P( IBA-co-DMAEMA)-b-PHPA),并用凝胶渗透色谱(GPC)、核磁共振波谱(1H-NMR)及红外光谱(FTIR)对其进...     

AB型聚乙二醇单甲醚-聚(L-丙氨酸)嵌段共聚物自组装过程的核磁共振研究

利用核磁共振方法研究了AB型双嵌段共聚物(MPEG45-b-PA32)在选择性溶剂中的自组装行为及胶束化过程.嵌段共聚物在三氟乙酸中聚氨基酸和聚乙二醇链段均处于自由运动状态,聚丙氨酸链段为无规线团结构.在向该溶液中逐渐加入氘代水的过程中,聚丙氨酸链段又重新聚集形成规整的二级结构.结合1H-NMR和COSY谱分析,结果显示这一自组装过程伴随着聚(L-丙氨酸)链段由无规线团向α-螺旋结构的构象转变,同时嵌段共聚物逐渐形成核-壳型胶束结构.利用透射电镜观察了所形成胶束的形态,嵌段共聚物主要形成粒径150 nm到220 nm的球形胶束.     

Removal of cadmium ions using micellar-enhanced ultrafiltration with mixed anionic-nonionic surfactants

Micellar-enhanced ultrafiltration (MEUF) was used to remove cadmium ions from wastewater efficiently. In this study the nonionic surfactants polyoxyethyleneglycol dodecyl ether (Brij35) and polyoxyethylene octyl phenyl ether (TritonX-100) were for micellar-enhanced ultrafiltration to lower the dosage of the anionic surfactant sodium dodecyl sulfate (SDS). The surfactant critical micelle concentration (CMC) and the degree of micelle counterion binding were investigated. The effects of nonionic surfactant addition on the efficiency of cadmium removal, the residual quantities of surfactant, the permeate flux and the secondary membrane resistance were investigated. A comparison between MEUF with SDS and MEUF with mixed anionic–nonionic surfactants was undertaken. The results show that the addition of Brij35 or TritonX-100 reduced the CMC of SDS and the degree of counterion binding for the micelles. Due to these variations the Cd²⁺ rejection efficiency was at a maximum when the Brij35:SDS and the TritonX-100:SDS molar ratio was 0.5. The Cd²⁺ rejection efficiency in MEUF with SDS is higher than for MEUF with mixed surfactants when the total dose of surfactant is constant. The permeate flux of MEUF with SDS is higher than that for MEUF with mixed surfactants while the secondary resistance of MEUF with SDS is less than that of MEUF with mixed surfactants.     

基于温敏性双亲嵌段共聚物的纳米胶束作为药物载体的研究

温度敏感性双亲嵌段共聚物由于其潜在的应用价值而引起广泛的关注。在药物控制释放领域,基于温敏性嵌段共聚物的纳米胶束作为药物载体显示了诸多特异的性能。在嵌段共聚物中引入具有温度敏感性的链段,使聚合物胶束具备天然被动靶向功能的同时,赋予了其主动靶向给药功能。本文从温度敏感性双亲嵌段共聚物的分子设计、合成、自组装性质和胶束的载药释药行为等方面进行了相关总结。重点介绍了含聚N-异丙基丙烯酰胺链段双亲嵌段共聚物的相关研究进展。     

胶束介质中丁二酮增溶位点的室温燐光碎灭法研究

采用丁二酮室温光猝灭法研究了胶束介质中丁二酮的增溶位点，通过研究4种不同荷电和不同亲水亲脂性的光猝灭剂以及盐效应等对Stern－Volmer常数的影响，表明了二酮在SDS、CTAB的胶束中是增溶在胶团的栏栅并靠近离子头基一侧和头基／水界面附近，而在CTAB胶束中更加趋向于胶团外部头基附近．