光敏性无规-类接枝双亲聚合物的合成与自组装行为的研究

通过ε 己内酯改性丙烯酸酯 (FAn ,n =1～ 4 )与肉桂酰氯反应合成了一系列光敏性大单体 (FAnC ,n =1～ 4 ) ,以FAnC与甲基丙烯酸 (MAA)进行自由基聚合 ,制备具有光敏性的双亲无规 类接枝共聚物 (PMFAnC) .用红外光谱、凝胶渗透色谱、核磁共振和差示扫描量热仪等对共聚产物进行了表征 .双亲性PMFAnC可以在选择性溶剂中进行自组装 ,形成以PMFAnC中PFAnC疏水链段为核 ,PMAA亲水链段为壳的高分子胶束 .核内的肉桂酰基由紫外光引发发生光交联反应 ,得到具有稳定壳 核结构的胶束 .动态激光光散射、透射电子显微镜结果表明 ,PMFAnC在水溶液中形成了一定结构的光敏性纳米胶束 ,在紫外光照射下PMFAnC胶束内核发生光聚合反应使胶束粒径减小     

双亲嵌段聚合物的合成与应用

本文介绍了双亲嵌段聚合物的合成方法，包括共溶剂法、聚合后功能化法、胶束聚合法、自由基界面聚合法等，以及双亲嵌段聚合物在乳液聚合、三次采油、医用高分子材料等方面的应用。     

光敏感双亲性梳状SMA聚合物的合成及其胶束化

以含香豆素型苯乙烯类光敏单体(coumarin-containing styrene monomer, CS)与苯乙烯(St)、马来酸酐(MA)为反应单体, 以偶氮二异丁腈(AIBN)为引发剂制备了光敏感三元苯乙烯-马来酸酐共聚物(SMA)双亲交替聚合物P(St/CS-alt-MA), 再利用羧酸酐基元与正辛胺的室温胺解反应获得光敏感双亲性梳状聚合物P(St/CS-alt-MAA8). 用傅立叶变换红外光谱(FTIR)、凝胶渗透色谱(GPC)、1H核磁共振(1H-NMR)等对该双亲梳状聚合物进行结构表征. 通过香豆素基元的光二聚作用, 使梳状聚合物溶解在DMSO中进行光照预交联; 非交联与预交联聚合物分别在选择性溶剂中自组装形成胶束; 利用羧酸基元与NaOH的离子化作用改变聚合物胶束的亲疏水性质. 动态激光光散射(DLS)与芘荧光探针实验表明预交联聚合物胶束较非交联胶束粒径大, 负载芘的能力强; 离子化作用使聚合物胶束解离重组成粒径更小的胶束, 但预交联胶束较非交联胶束小, 离子化后胶束疏水微区更加紧密, 负载芘的能力也增大.     

核-壳结构微球的制备进展

综述了近年来核-壳结构微球制备方面的研究进展,介绍了高分子胶束交联、模板逐层组装、模板微球表面原位引发聚合、动态溶胀法、种子聚合法以及溶胶-凝胶法等主要制备方法,并对各种方法所涉及的核-壳微球形成机理进行了必要阐述.     

RAFT聚合法制备聚合物胶束及其应用前景

聚合物胶束由于具有优良的组织渗透性、增容效果好、结构多样性和热稳定性等特点,成为国内外研究的热点之一。本文综述了近几年发展起来的一些具有特殊结构和特殊性能的双亲性嵌段聚合物胶束的研究进展,详细阐述了RAFT聚合法合成聚合物胶束的机理和优势,表明了RAFT聚合法可直接在水溶液中方便快捷地制备出温度和pH双响应性聚合物胶束。然而,当聚合物胶束的浓度低于其临界胶束浓度时,胶束的稀释效应大大影响了其实际应用,为提高聚合物胶束的稳定性,文章归纳总结了一系列有关壳交联聚合物胶束的制备方法及研究进展。最后,文章展望了聚合物胶束在药物可控释放、靶向、生物成像、催化剂负载及其他领域的应用前景。     

双亲性无规光敏共聚物的疏水基元对其自组装胶束乳化性能的影响

设计合成了一系列具有不同化学组成的双亲性无规光敏共聚物,聚(7-对乙烯基苄氧基-4-甲基香豆素-r-丙烯酸)(P(VM-r-AA)),通过选择性溶剂法自组装获得纳米胶束,并将纳米胶束用作大分子颗粒乳化剂,研究其在甲苯-水界面的稳定性能。研究表明:聚合物疏水基元含量的增加使自组装胶束结构由溶胀的微凝胶状向刚性颗粒状转变;同时,胶束初始乳化效率增加,但油水界面吸附稳定性显著下降。此外,通过对疏水基元PVM的摩尔分数为12%的胶束进行辐照交联,并研究其在不同pH下的乳化性能,结果表明:胶束表面溶胀的双亲性链段对其乳化性能产生了重要的影响。未交联的胶束保持着良好的乳化性能;而交联的胶束形变能力变差、刚性增强,在碱性条件下,彻底失去乳化能力。     

聚二甲基硅氧烷接枝二甲基丙烯酰胺的制备及其胶束化研究

高分子胶束具有低临界胶束浓度(CMC)、稳定性高等优点,在药物输送和药物控制缓释等诸多领域显示出很好的应用前景[1].在生物体内应用对高分子胶束的生理相容性和无毒副作用的要求是关键点.有机硅具有的生理相容性、无毒副作用,是其它纯碳骨架聚合物所不能比拟的[2].因此,合成基于聚硅氧烷的两亲性共聚物以及利用它们制备胶束的工作越来越受到人们的重视[3].本文以侧基带环氧基团的聚硅氧烷和亲水性大分子单体通过环氧基团的开环反应制得两亲性共聚物,并通过荧光光谱和激光光散射研究了两亲性共聚物的胶束化行为.     

核交联的含磺酸甜菜碱pH敏感胶束的制备与表征

制备了一种在疏水段带有侧基叠氮官能团的两亲性pH敏感的聚合物——聚己内酯-聚(甲基丙烯酸二乙氨基乙酯-磺酸甜菜碱)((PCL-ACL)-PDEAS);同时合成了两端带有炔基中间带有二硫键的交联剂,用红外、核磁表征了目标分子.通过两亲性高分子自组装形成胶束,并通过点击化学反应获得了核交联的胶束.通过动态光散射测定粒径,胶束酸碱滴定表征胶束的pH敏感性,还原条件下释放药物的速度,对比了非交联胶束和交联胶束的性质.结果表明,交联胶束在正常生理条件下的释放速度比未交联胶束更慢;而在有DTT的存在条件下,交联胶束由于二硫键断裂,释放速率明显加快.因此,核交联载药胶束有可能响应肿瘤的微环境实现靶向释放.     

高分子胶束化的新途径及胶束的结构演化

简述了嵌段共聚物和接枝共聚物在选择性溶剂中的胶束化行为，详细讨论了导致高分子胶束化的一些新途径，如利用特殊相互作用（氢键、离子相互作用 高分子／金属离子配合络合）、改变温度、介质环境和化学反应诱导等；并对高分子胶束结构的进一步演化以获得核交联和壳交联胶束作了简要的介绍。     

点击化学在生物医用高分子中的应用

点击化学的概念提出不到10年,由于其反应条件温和,反应效率高,产物后处理简单等诸多优点而备受关注。本文概述了点击化学技术应用于生物医用高分子材料的合成,主要介绍了铜催化叠氮炔环加成(copper-catalyzed azide-alkyne cycloaddition)点击化学合成和制备多功能性和智能响应性高分子用于非病毒高分子基因载体、高分子胶束药物载体和水凝胶控制释放体系等的研究和最新进展,提出了点击化学在生物医用高分子材料合成中应用的主要问题,并对其发展前景进行了展望。     

两亲嵌段共聚物胶束用作医用材料

两亲嵌段共聚物可以在水溶液中自组装形成亲水性链段为外壳、疏水性链段为内核的胶束,这种胶束能够用作药物载体而引起人们极大的关注。本文综述了两亲嵌段共聚物胶束用作医用材料的研究进展,主要内容包括医用两亲嵌段共聚物的种类,胶束化,以及用作诊断试剂载体、药物缓释载体、靶向载体等。两亲嵌段共聚物胶束用作磁共振造影剂载体有利于肿瘤的诊断,用作药物缓释载体可以有效增溶难溶性抗肿瘤药物,延长药物在体内的血液循环时间。此外,通过对胶束表面进行修饰或者施加外场,还可以实现靶向功能。因此,两亲嵌段共聚物胶束在医用材料领域有着广阔的发展前景。     

Efficient synthesis of single gold nanoparticle hybrid amphiphilic triblock copolymers and their controlled self-assembly

We report on a robust approach to the size-selective and template-free synthesis of asymmetrically functionalized ultrasmall (<4 nm) gold nanoparticles (AuNPs) stably anchored with a single amphiphilic triblock copolymer chain per NP. Directed NP self-assembly in aqueous solution can be facilely accomplished to afford organic/inorganic hybrid micelles, vesicles, rods, and large compound micelles by taking advantage of the rich microphase separation behavior of the as-synthesized AuNP hybrid amphiphilic triblock copolymers, PEO-AuNP-PS, which act as the polymer-metal-polymer analogue of conventional amphiphilic triblock copolymers. Factors affecting the size-selective fabrication and self-assembly characteristics and the time-dependent morphological evolution of NP assemblies were thoroughly explored.     

Hybrid Surfactant Systems with Inorganic Constituents

Surfactants are molecules of enormous scientific and technological importance, which are widely used as detergents, emulsifiers, and for the preparation of diverse nanostructures. Their fascinating ability to form self‐organized structures, such as micelles or liquid crystals, originate from their amphiphilic architecture—a polar head group linked to a hydrophobic chain. While almost all known surfactants are organic, a new family of surfactants is now emerging, which combines amphiphilic properties with the advanced functionality of transition‐metal building blocks, for example, redox or catalytic activity and magnetism. These hybrid surfactants exhibit novel self‐organization features because of the unique size and electronic properties of the metal‐containing entities.     

Linear‐dendritic polymeric amphiphiles as carriers of doxorubicin—In vitro evaluation of biocompatibility and drug delivery

In our recent work, we have explored the formation of chemotherapeutic delivery vehicles constructed from four different amphiphilic linear‐dendritic hybrid block copolymers. These micelles were found to form about 100‐nm‐sized structures that were capable of sequestering doxorubicin at loading efficiencies up to 22%. Here, the cellular toxicity of these biocompatible and biodegradable linear‐dendritic hybrid materials was evaluated on two breast cancer cell lines and primary human macrophages. The micelles were found not to affect the cellular viability at concentrations below 35 μg mL^?1. After drug loading, these constructs could deliver an efficient dose of drugs, resulting in significant decreases in cell viability. Kinetic studies indicated that the drug formulation in the polymer micelles slowed down the cell uptake compared with the nonformulated drug, but similar efficacy in viability reduction and cell apoptosis were found. Taken together, these linear‐dendritic hybrid materials represent an interesting novel architecture for the construction of drug delivery systems. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Controlled Self-assembly of Thermo-responsive Amphiphilic H-shaped Polymer for Adjustable Drug Release

Despite the fact that some progress has been made in the self-assembly of H-shaped polymers,the corresponding self-assemblies that respond to external stimulus and are further utilized to adjust the release of drugs are still deficient.The stimuli-responsive segments with amphiphilic H-shaped structure are generally expected to enhance the controllability of self-assembly process.The synthesis and self-assembly behavior of thermo-responsive amphiphilic H-shaped polymers with poly(ethylene glycol) (PEG),polytetrahydrofuran (PTHF) and poly(N-isopropyl acrylamide) (PNIPAM) as building blocks are reported in this paper.The inner architecture structure and size of complex micelles formed by H-shaped self-assemblies were effectively adjusted when the solution temperature was increased above the lower critical solution temperature of PNIPAM segments.Furthermore,it was found that the architecture of self-assemblies underwent a transition from the complex micelles based on primary micelles with hybrid PEG/PNIPAM shells to large complex micelles based on primary micelles with hybrid PTHF/PNIPAM cores and PEG shells during the thermal-induced self-assembly process.The adjustable release rate of doxorubicin (DOX) from the DOX-loaded complex micelles and basic cell experiments further proved the feasibility of these self-assemblies as the thermal-responsive drug delivery system.     

Conventional synthesis of amphiphilic block copolymer utilized for polymeric micelle by mechanochemical solid-state polymerization

The first example is presented here of an amiphiphilic block copolymer synthesized by mechanochemical solid-state polymerization and used to form polymeric micelles. A model amphiphilic block copolymer was synthesized first, possessing galactose as a hydrophilic side chain and theophylline as a hydrophobic side chain, by mechanochemical solid-state polymerization. The resulting copolymer had a narrow molecular weight distribution. Polymeric micelle formation was subsequently carried out with the copolymer by a dialysis method. To gain insight into the physicochemical properties of the polymeric micelle, dynamic light scattering (DLS) measurements were performed. A narrow distribution of diameters was observed in the polymeric micelle solution, and these micelles were disrupted by the addition of sodium dodecyl sulfate (SDS). It was also confirmed by DLS measurements that the polymeric micelles were spherical. These results suggested that the block copolymer synthesized by mechanochemical solid-state polymerization was as suitable for the preparation of polymeric micelles as materials obtained by living polymerization.     

Functional and site-specific macromolecular micelles as high potential drug carriers

Since several years, macromolecular micelles based on amphiphilic block copolymers have attracted much interest as drug carriers. These micelles show a long term blood circulation time resulting from their small diameter and the steric repulsion created by the poly(ethylene oxide) chains which constitute micelle corona, as well as from their high thermodynamic stability. Besides this long term blood circulation time generating a passive targeting, an active targeting, chemical or physical affinity targeting, might allow the preparation of more efficient drug carriers. In order to obtain such double targeting properties, we have prepared two kinds of macromolecular micelles. The first one is based on amphiphilic poly(ethylene oxide)/poly(β-benzyl -aspartate) ---PEO/PBLA--- block copolymers having hydroxy groups at the free end of PEO chains. As a result of their structure, such micelles have hydroxy groups on their outer-shell which can be further modified in order to introduce a targeting moiety (sugar, etc.). The characteristics (diameter, critical micellar concentration (cmc), drug loading capacity) have been determined. Moreover, doxorubicin loaded -hydroxy PEO/PBLA micelles have been shown to be slightly more cytotoxic than the corresponding -methoxy PEO/PBLA micelles. The second type of micelles is based on thermosensitive amphiphilic poly(N-isopropyl acrylamide)/polystyrene ---PIPAAm/PSt--- block copolymers. Such micelles have a small diameter and a low cmc in addition to thermosensitivity properties which are similar to those of PIPAAm.     

Synthesis of size-controlled acid-resistant hybrid calcium carbonate microparticles as templates for fabricating "micelles-enhanced" polyelectrolyte capsules by the LBL technique

Size-controlled, low-dispersed calcium carbonate microparticles were synthesized in the presence of the amphiphilic block copolymer polystyrene-b-poly(acrylic acid) (PS-b-PAA) by modulating the concentration of block copolymer in the reactive system. This type of hybrid microparticles have acid-resistant properties. By investigating the aggregation behaviors of PS-b-PAA micelles by transmission electron microscopy (TEM), the mechanism of hybrid calcium carbonate formation illustrated that the block copolymer served not only as "pseudonuclei" for the growth of calcium carbonate nanocrystals, but also forms the supramicelle congeries, a spherical framework, as templates for calcium carbonate nanocrystal growth into hybrid CaCO(3) particles. Moreover, this pilot study shows that the hybrid microparticle is a novel candidate as a template for fabricating multilayer polyelectrolyte capsules, in which the block copolymer is retained within the capsule interior after core removal under soft conditions. This not only facilitates the encapsulation of special materials, but also provides "micelles-enhanced" polyelectrolyte capsules.     

Synthesis and applications of shell cross-linked thermoresponsive hybrid micelles based on poly(N-isopropylacrylamide-co-3-(trimethoxysilyl)propyl methacrylate)-b-poly(methyl methacrylate)

Shell cross-linked (SCL) thermoresponsive hybrid micelles consisting of a cross-linked thermoresponsive hybrid hydrophilic shell and a hydrophobic core domain were synthesized from poly(N-isopropylacrylamide-co-3- (trimethoxysilyl)propyl methacrylate)-b-polymethyl methacrylate (P(NIPAAm-co-MPMA)-b-PMMA) amphiphilic block copolymers. Transmission electron microscopy (TEM) images showed that the SCL micelles formed regularly globular nanoparticles. The SCL micelles showed reversible dispersion/aggregation in response to temperature cycles through an outer polymer shell lower critical solution temperature (LCST) for PNIPAAm at around 33 degrees C, observed by turbidity measurements and dynamic light scattering (DLS). The drug loading and in vitro drug release properties of the SCL micelles bearing a silica-reinforced PNIPAAm shell were further studied, which showed that the SCL micelles exhibited a much improved entrapment efficiency (EE) as well as a slower release rate which allowed the entrapped molecules to be slowly released over a much longer period of time as compared with pure PNIPAAm-b-PMMA micelles.     

功能性两亲嵌段共聚物的研究进展

功能性两亲嵌段共聚物因自身独特的性质而在靶向输送、控制释放、分子识别等领域得到广泛的应用.本文对这类嵌段共聚物的合成方法、其胶束的形成机理、制备形式、表征手段以及一些常见的具有光学活性的两亲嵌段共聚物及其应用进行了综述.