β-环糊精聚轮烷的合成及其细胞摄取行为的研究

以聚丙二醇-双[3,4,5-三(炔丙氧基)苯甲酰胺]为轴,以小体积的2-叠氮乙醇为封端剂通过水相炔-叠氮点击化学反应(Cu AAC)生成的多个三氮唑进行封端,合成了新型的β-环糊精聚轮烷.利用核磁氢谱和旋转坐标系欧沃豪斯增益谱对所合成的β-环糊精聚轮烷进行了结构表征.进一步通过聚轮烷上的羟基,在聚轮烷上依次共价连接了水溶性聚合物聚乙二醇和荧光分子FITC,对聚轮烷进行了亲水化改性和荧光标记,研究了改性后的聚轮烷的细胞毒性和细胞摄取行为,结果表明,改性后的聚轮烷具有良好的细胞相容性,并可通过胞吞的方式被细胞摄取.     

基于环糊精的(准)聚轮烷研究进展

环糊精聚轮烷作为超分子化学的重要成员由于可潜在应用于分子机器、组织工程支架、人体生物传感器及药物控制释放载体等智能生物材料已成为国际化学及高分子科学的一个热点.本文介绍了基于环糊精的(准)聚轮烷最新研究进展,包括(准)聚轮烷合成新方法,聚轮烷的多种类型(如嵌段型、金属软连接型、星形、pH敏感型、侧链型、聚轮烷聚集体等),以及(准)聚轮烷形成机理研究,并进一步探讨了该领域的研究前景及有待解决的问题.     

具有“滑轮”效应聚轮烷交联剂的制备及在体膨颗粒型调驱剂中的应用

通过三步反应设计构筑了一种具有双键结构的改性α-环糊精聚轮烷,由于α-环糊精可以在聚乙烯醇链上滑动,因此可以将其视作一种具有"滑轮"效应的交联剂,通过红外光谱、二维核磁共振光谱及X射线衍射等表征了其结构.将新型聚轮烷交联剂和传统交联剂N,N'-亚甲基双丙烯酰胺分别与丙烯酰胺交联共聚制备体膨颗粒,测定其溶胀性能和形变性能.吸水膨胀51 h后,聚轮烷交联剂制备的体膨颗粒吸水倍率为8.32,受到294.3 N的外力再撤消后,体膨颗粒未破碎且能恢复至原始状态,而传统交联剂制备的体膨颗粒吸水倍率为6.75,受到112.4 N的外力后,体膨颗粒发生破碎.表明由聚轮烷交联剂制备的体膨颗粒具有更大的膨胀倍率和更优异的形变性能.     

葫芦脲的研究进展

近几年葫芦脲和其衍生物由于其特殊的结构与性质已引起的密切关注。本文综述了葫芦脲的最新研究进展,包括葫芦脲分子及其衍生物的分子设计与合成,与聚电解质形成主链（准）聚轮烷和侧链（准）聚轮烷,与其他有机客体小分子相互作用形成轮烷和准轮烷,以及葫芦脲分子及其衍生物在囊泡、二维聚合物、色谱固定相、生物体以及药物缓释方面的最新应用。     

点击化学法快速合成氨基酸功能化的环糊精聚轮烷

通过叠氮-炔环加成点击反应制备了各种氨基酸功能化的生物相容性β-环糊精封端的α-环糊精聚轮烷.利用FTIR和氢核磁共振谱对产物的结构进行了表征.结果证明对于空间位阻较小的分子,点击反应能够在很短的时间(几分钟)内达到近100%的转化率.点击化学为功能化聚轮烷的制备提供了快速有效的新途径.     

α-环糊精准轮烷/N-异丙基丙烯酰胺交联共聚温敏型超分子结构水凝胶的制备与表征

采用一锅法合成了甲基丙烯酰基封端的聚乳酸-聚乙二醇-聚孔酸(PLA-PEG-PLA)三嵌段大分子单体,然后再通过与α-环糊精进行超分子自组装,得到聚准轮烷.将制备的聚准轮烷悬浮在N-异丙基丙烯酰胺水溶液中,再加入适量的光引发剂,在紫外光的照射下,溶液快速固化,得到了具有超分子结构的温敏型凝胶体.采用FTIR、TG、XRD等分析手段对所得聚准轮烷及其水凝胶进行了表征.     

具有pH-响应性的聚天冬氨酸类载药胶束的制备和释放能力研究

通过大分子引发剂ω-氨基-α-甲氧基聚乙二醇引发N-羧基-α-氨基环内酸酐开环聚合和水合肼侧基改性,制备了一系列聚乙二醇-聚氨基酸类三嵌段共聚物.其中聚氨基酸链段包括具有酰肼基的聚天冬氨酸衍生物(PAHy),以及疏水性的聚丙氨酸链段.引入具有pH响应性的腙键键合阿霉素,利用键合阿霉素与游离阿霉素之间的π-π叠合作用,在聚合物自组装形成胶束过程中通过化学键合+物理包埋的方式充分负载药物.该胶束以聚丙氨酸链段为核心,以PEG链段为冠层,以PAHy链段为包裹药物的壳层.载药胶束的粒径在170 nm左右.研究不同pH值条件下载药胶束的药物释放能力,随环境pH值的降低药物的释放速率显著增加.     

葫芦脲超分子(准)聚轮烷的研究进展

综述了一类新型超分子葫芦脲(准)聚轮烷的最新研究进展,包括一维、二维、三维金属(准)聚轮烷,主链、侧链有机(准)聚轮烷和树状大分子(准)聚轮烷的最新研究情况,并对超分子(准)聚轮烷的前景进行了展望。     

环糊精与聚1,3-二氧五环结晶内含复合物的合成与表征

合成并表征了环糊精与聚1,3-二氧五环的结晶内含复合物.聚1,3-二氧五环分子链上较高的氧原子密度使其能与3种常见的环糊精均形成结晶内含复合物.使用了红外光谱, 热重分析,X射线衍射,氢核磁共振,¹³C NMR,电子扫描显微镜对结晶内含复合物进行了研究.通过热重分析发现,结晶内含复合物比纯的环糊精更稳定.X射线衍射显示结晶内含复合物为隧道状结构.通过固体碳13交叉极化/魔角自旋核磁共振可以看出,在结晶内含复合物中环糊精的构象非常对称,而纯环糊精分子本身的构象不够对称.通过电子扫描显微镜观察了α -环糊精与聚1,3-二氧五环结晶内含复合物的表面形貌.     

基于水溶性嵌段共聚物的双动态共价键交联凝胶的构建

本文采用可逆加成-裂解链转移(RAFT)聚合制备了含酰肼基和硼酸基团的N-异丙基丙烯酰胺双嵌段聚合物和含有酮羰基和葡萄糖基团的丙烯酰胺双嵌段聚合物.在不同条件下构筑了基于酰腙键和硼酸酯键交联的双动态共价键交联水凝胶,通过对其流变行为的测试探究了凝胶的综合性能.酸性条件下,硼酸酯键不能形成,酰腙键使凝胶快速形成并实现快速...     

Synthesis of a biodegradable polymeric supramolecular assembly for drug delivery

A novel design of a biodegradable carrier for drug delivery was established by constructing a supramolecular assembly of drugs and polymer backbones without any covalent bonds. A biodegradable polyrotaxane was synthesized in which α-cyclodextrins (α-CDs) as drug carriers were threaded onto poly(ethylene glycol) chains which then were capped at each chain end by L -phenylalanine via peptide linkages. The release of α-CDs was observed only when the terminal peptide linkages were degraded.     

Thermally switchable polyrotaxane as a model of stimuli-responsive supramolecules for nano-scale devices

A polyrotaxane consisting of many β-cyclodextrins (β-CDs) and a triblock copolymer of poly(ethylene glycol) (PEG) and poly(propylene glycol) (PPG) capped with bulky end-groups was synthesized as a model of stimuli-responsive supramolecules for nanoscale devices. The polyrotaxane was reversibly soluble-insoluble in water in response to temperature. This was achieved through the assembled and dispersed states of β-CDs along the block copolymer. It is considered that intermolecular hydrogen bondings of β-CDs, as well as the PEG segment length of the copoloymer, are predominant factors for regulating such thermally switchable behavior of the polyrotaxane.     

Pseudopolyrotaxanes on inorganic nanoplatelets and their supramolecular hydrogels

In this paper, we demonstrate the first hybrid suprastructure of pseudopolyrotaxanes (PPRs) on clay nanoplatelets. Simple end-modification of poly(ethylene glycol) with pyridinium (PEG-N(+)) enabled the chains to form brushlike conformation on clay surfaces. Thus, the PEG chains were able to thread into the cavities of α-cyclodextrins (α-CDs), leading to hybrid PPR hydrogels. This was very different from the unmodified PEG chains, which were absorbed onto the clay surface and thus made the PPR formation impossible. The hydrogels made of this PPR-on-clay structure displayed a dynamic modulus 1 order of magnitude higher than those of the native PPR hydrogels. Furthermore, based on the competitive host-guest interactions, such hybrid hydrogels showed fully photoreversible sol-gel transition after a competitive guest containing azobenzene moiety was introduced.     

超临界二氧化碳中甲基-β-环糊精与聚丙二醇的包合

探索了超临界二氧化碳介质中甲基-β-环糊精和两种线型聚丙二醇间的穿合(threadinginclusion);并和相同温度下空气中的固态包合反应进行了比较。在无溶剂状态下,原处于无定形态的甲基-β-环糊精可与聚丙二醇链作用形成具有圆筒状结构的结晶态包合物,引入适量二氧化碳可明显增大包合反应的程度;将聚丙二醇链两端的羟基换为丙烯酸酯基可使反应进一步加强。     

One‐pot synthesis of polyrotaxane by clipping and cyclopolymerization of α,ω‐diethynyl isophthalamide with pyridiniumdicarboxamide chloride

The one‐pot synthesis of a main chain‐type polyrotaxane composed of axle molecules threaded through the macrocyclic units on the polymer main chain was achieved via the combination of cyclopolymerization and clipping procedures. The cyclopolymerization of an α,ω‐diethynyl monomer bearing an isophthalamide moiety ( 1 ), which clips onto an axle component bearing a pyridiniumdicarboxamide moiety ( 2·Cl ) through a chloride anion was carried out in chloroform with the monomer concentration of 0.06 mol L^?1 at 40 °C using [Rh(nbd)Cl]₂/Et₃N as a catalyst to afford a gel‐free polymer. The resulting polymer was assigned to the main chain‐type polyrotaxane with a poly(phenylacetylene) backbone (poly‐ 3·Cl ) based on size exclusion chromatography and ¹H NMR measurements. The diffusion‐order two‐dimensional NMR and circular dichroism spectra provided definitive proof of the rotaxaned architecture in the polymer. The mole fraction of the rotaxane unit in the total cyclic repeating unit was determined to be 26.3%. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Mobility Tuning of Polyrotaxane Surfaces to Stimulate Myocyte Differentiation

Polyrotaxanes, consisting of poly(ethylene glycol) and α‐cyclodextrins, are mechanically interlocked supermolecules. The structure allows α‐cyclodextrins to move along the polymer, referred to as molecular mobility. Here, polyrotaxane‐based triblock copolymers, composed of polyrotaxanes with different degrees of methylation and poly(benzyl methacrylate) at both terminals, are coated on culture surfaces to fabricate dynamic biointerfaces for myocyte differentiation. The molecular mobility increases with the degree of methylation and the contact angle hysteresis of water droplets and air bubbles. When the mouse myoblast cell line C2C12 is cultured on methylated polyrotaxane surfaces, the expression levels of myogenesis‐related genes, myogenin (Myog) and myosin heavy chain (Myhc) are altered by the degree of methylation. Polyrotaxane surfaces with intermediate degrees of methylation promote the highest expression levels among all the surfaces. The polyrotaxane surface provides an appropriate environment for myocyte differentiation by accurately adjusting the degrees of methylation.     

Control of the Optical Properties of a Star Copolymer with a Hyperbranched Conjugated Polymer Core and Poly(ethylene glycol) Arms by Self‐Assembly

A self‐assembly approach to tuning the optical properties of a star copolymer is reported herein. The star copolymer HCP‐star‐PEG with a hyperbranched conjugated polymer (HCP) core and many linear poly(ethylene glycol) (PEG) arms has been prepared successfully. The HCP core was synthesized by Wittig coupling of N‐(n‐hexyl)‐3,6‐diformylcarbazole and 1,3,5‐bis[(triphenylphosphonio)methyl]benzene tribromide. Subsequently, the linear PEG arms were grafted onto the HCP core by acylhydrazone connection. It was found that the optical properties of HCP‐star‐PEG in chloroform solution changed on addition of acid. Both ¹H NMR and UV/Vis spectroscopic investigations confirmed that the variation of the optical properties was related to the complexation of the acid and the imine bond in the acylhydrazone group. HCP‐star‐PEG self‐assembled into core–shell micelles in the mixed solvent of chloroform and acetonitrile, which affected the protonation of the imine bond. Therefore the optical properties of HCP‐star‐PEG can be readily controlled by self‐assembly.     

Synthesis and characterization of a novel hydroxypolyether blocked polydimethylsiloxane PEO-b-PDMS-b-PEO

A novel hydroxypolyether blocked polydimethylsiloxane, poly（ethylene oxide） propyl-b-polydimethylsiloxane-b-propyl poly（ethylene oxide） （PEO-b-PDMS-b-PEO） was synthesized by simple hydrosilation reaction of poly（ethylene glycol） monoallyl ether with α,ω-dihydrogen terminated PDMS （HPDMS）. Fourier transform infrared spectroscopy （FTIR） and IH NMR were used to identify the structure of PEO-b-PDMS-b-PEO and intermediate product HPDMS. Based on the effect investigations of temperature, reactant molar ratio, catalyst and time on the hydrosilation, it was found that the conversion of Si-H bond to SiC bond increased with the increase of catalyst and time, and the reaction completed when the content of catalyst was 22μg/g and the time was 5 h, respectively. Urethane reaction of OH and NCO group confirms that PEO-b-PDMS-b-PEO is more reactive toward to diisocyanate than α,ω-dihydroxylbutyl terminated PDMS.     

Supramolecular design for multivalent interaction: maltose mobility along polyrotaxane enhanced binding with concanavalin A

High molecular mobility of maltose-conjugated alpha-cyclodextrins (alpha-CDs) along a poly(ethylene glycol) (PEG) chain due to the mechanically locked structure of polyrotaxanes enhanced multivalent interactions between maltose and concanavalin A (Con A). When maltose groups are conjugated with alpha-CDs that were threaded onto a PEG capped with benzyloxycarbonyl l-tyrosine (polyrotaxane), Con A-induced hemagglutination was greatly inhibited by polyrotaxanes with a certain threading % of alpha-CDs. Such an inhibitory effect was significantly superior to the other type of conjugates, in which poly(acrylic acid) was used as a backbone for maltose conjugation. The spin-spin relaxation time (T2) of the maltose C(1) proton in the polyrotaxane at a typical alpha-CD threading % was significantly larger than that of any other conjugate, which was well related to the inhibitory effect. Therefore, we concluded that the high mobility of maltose groups along the polyrotaxane structure contributes to enhanced Con A recognition.