Fabrication of tunable colloid crystals from amine-terminated polyamidoamine dendrimers

A pH-responsive colloidal crystal was assembled using core-shell composite spheres, poly(styrene-methyl methacrylate-acrylic acid) (P(St-MMA-AA)) spheres covered by generation 4 amine-terminated polyamidoamine dendrimers. The light reflection of the colloidal crystal film can be tuned at different pH due to different protonation level of the dendrimers. The method shows a facile way to fabricate diffraction-based chemical and biological sensors by exploiting the effect of photonic crystal cooperated with tunable nanoparticles.     

温度及pH敏感的树枝状高分子衍生物合成及药物控制释放研究

对合成的系列聚酰胺-胺型(PAMAM)树枝状高分子进行端基的羟基化和氯乙酰化两步修饰,使PAMAM最外层接上烷基氯.以修饰产物为引发剂,通过原子转移自由基引发甲基丙烯酸N,N-二甲氨基乙酯(DMAEMA)聚合得到树枝状PAMAM高分子衍生物,并对其结构用FTIR、1H-NMR和粒径分析进行了表征.紫外可见分光光度仪测定证实此高分子具有温度及pH敏感性.通过对小分子药物控制释放研究表明,此树枝状高分子衍生物通过环境pH值可有效地控制小分子药物的释放.     

Fundamental studies on the intermediate layer of a bipolar membrane: Part III. Effect of starburst dendrimer PAMAM on water dissociation at the interface of a bipolar membrane

Starburst dendrimer polyamidoamine (PAMAM) with ellipsoidal or spheroidal shape is structure-regular and has much more amino groups than conventional polymers. This paper investigates the possibility of these amino groups on water dissociation in a bipolar membrane interface. To do this, a bipolar membrane is prepared by casting the solution of sulfonated poly(phenylene oxide) (SPPO) in dimethyl formamide (DMF) on a commercial anion exchange membrane that is immersed in PAMAM aqueous solution in advance. The existence of PAMAM adsorbed on the membrane is proved by X-ray photoelectron spectroscopy (XPS), and the adsorption amount is evaluated by weighting method. The junction thickness of the prepared bipolar membrane is determined by electrochemical impedance spectroscopy (EIS), and the performance is evaluated by current–voltage curves. The experiments show that both the generation and concentration of PAMAM would strongly affect the characteristics of the bipolar membranes. There exists a transitional concentration for various generations PAMAMs to catalyze effectively the water dissociation, and above or below the transitional concentration the performance of bipolar membranes is decreasing. The higher the generation, the lower the concentration. Moreover, at a fixed solution concentration, there is not the simple relation of monotone decreasing or increasing between the performance of bipolar membranes and the generations of PAMAMs. All these can be explained according to the characteristics of PAMAMs combined with available water dissociation theory.     

高效液相色谱和热重分析在树形聚酰胺胺合成中的应用

优化了聚酰胺胺树形分子合成工艺条件，采用HPLC和热重分析（TG）相结合的方法对所合成的树形聚酰胺胺进行分析与表征；HPLC的分析表明，在各不同代的目标化合物中，均有反应物单体存在，在高代产物中除了含有少量反应物外，还有少量的低代数分子；TG分析表明，产物中小分子反应物占的比例很少，一般为2％－3％左右，如果将减压蒸馏后的产物重新进行真空干燥，对半代树形大分子，能进一步有效除去小分子反应物，而对于整数代树形大分子，则效果并不理想。     

Fluorophore-labeled Polyamidoamine (PAMAM) Dendritic Architectures: Synthesis and Fluorescence Sensing Properties

Novel polyamidoamine (PAMAM) dendrimers (G=0.5–2.5) with a naphthalene core unit have been prepared. They were found to display acid as well as metal ion sensitive fluorescence signal amplification, making them of potential use as chemosensing materials. PAMAM dendritic wedges as well as naphthalene-centered PAMAM dendrimers were characterized by FT-IR, ¹H and ¹³C NMR spectroscopic methods and elemental analysis.     

Low generational polyamidoamine dendrimers to enhance the solubility of folic acid:A‘‘dendritic effect’’investigation

Low generational(G0–G2,G for generation) polyamidoamine(PAMAM) dendrimers were investigated as enhancers to improve the aqueous solubility of folic acid at pH 11 and pH 5.In these two cases,the solubility of folic acid increases with both the dendrimer concentration and generation.However,the solubilization mechanism is different.The electrostatic interaction between the primary amines of dendrimers and the ionized carboxylic groups of folic acid dominates the dissolution process at pH 11 while the increase of the solubility of folic acid at pH 5 is attributed to the hydrophobic encapsulation inside the dendrimer molecules.In addition,for comparison ethylenediamine was used as a small molecule control to examine the ‘‘dendritic effect' in the dendrimer-related solubilization process.Interestingly,PAMAM dendrimers exhibit,at pH 5,a significant superiority over ethylenediamine in enhancing solubility,whereas this ‘‘dendritic effect' cannot be observed under the basic condition.     

Cu2+对联苯甲醛修饰的树状大分子聚酰胺-胺荧光性能的影响

采用小分子联苯甲醛(BPA)分别修饰第一和第二代树状大分子聚酰胺-胺(PAMAM), 合成了2种PAMAM的修饰产物G1-BPA4和G1-BPA8. 利用IR, 1H NMR及MALDI-TOF MS等手段表征了2种产物的结构, 研究了Cu2+浓度对其荧光性能的影响. 结果表明, 在一定的浓度范围内, 作为常见荧光猝灭剂的Cu2+能使2种产物的荧光均显著增强.     

生物材料聚酰胺-胺树状大分子在医学领域研究进展

聚酰胺－胺（PAMAM）树状大分子是一类新型纳米生物材料，这类分子可通过有机合成的方法精确控制分子的结构和相对分子质量，其独特的分子结构使之在许多领域获得广泛应用，本文着重介绍了PAMAM树状大分子作为基因载体，药物载体，磁共振造影剂和硼中子俘获治疗试剂等在医学领域中的研究进展。     

Synthesis and photoresponsive study of azobenzene centered polyamidoamine dendrimers

A new series of novel polyamidoamine (PAMAM) dendrimers 4, 5 and 6 possessing azobenzene units specifically at the core were prepared and their reversible trans/cis photoisomerization properties were studied. PAMAM dendritic wedges as well as azo-based PAMAM dendrimers were fully characterized by means of FT-IR, NMR (¹H and ¹³C), mass spectrometry (MALDI-MS), thermogravimetric and elemental analysis.     

树枝状高分子修饰的水溶性近红外二区荧光聚合物的合成及其在肿瘤相关抗原载运中的应用

通过在具有供体-受体-供体结构的近红外二区(NIR-Ⅱ)荧光分子(TTQ-F)的侧链上修饰聚酰胺-胺型树枝状高分子(PAMAM)合成了一种NIR-Ⅱ荧光高分子(TTQ-F-PAMAM).该树枝状修饰的高分子不仅可以实现在900～1200nm近红外二区范围的荧光成像,同时有着良好的光稳定性.PAMAM作为一种三维、高度有...