聚酰胺胺(PAMAM)树状分子的合成

介绍了聚酰胺胺(PAMAM)树状分子的三种合成方法,即发散合成法、收敛合成法以及发散收敛结合合成法的主要特点及其进展,探讨了各种方法的优缺点。发散合成法具有分子量增长迅速的优点,但是分离纯化步骤多;收敛合成法的特点是分子量分布窄,但是分子量增长慢;发散收敛结合合成法综合了发散合成法和收敛合成法的优点,很有发展前途。同时,提出了PAMAM树状分子合成研究发展方向。     

以酯端基PAMAM树形分子为模板在N，M-二甲基甲酰胺溶剂中制备金纳米粒子

用UV-vis、FT-IR光谱研究了HAuCl4和酯端基聚酰胺胺(PAMAM)树形分子在N，N-二甲基甲酰胺(DMF)溶剂中的相互作用，提出HAuCl4与树形分子之间的络合机理：[AuCl4]^-离子与质子化叔胺基团形成离子对，Au^3 离子与PAMAM树形分子上的酯基和酰胺基团形成配位作用。在DMF溶剂中酯端基PAMAM树形分子与HAuCl4配位后用柠檬酸钠还原形成金纳米粒子，UV-vis光谱和TEM图像分析表明了随树形分子代数的增加，金纳米粒子的直径减小，并提出了树形分子-金纳米复合物的结构模型：(1)较低代数的树形分子环绕在金粒子的外围；(2)在较高代数的树形分子空腔内部封装金纳米粒子。     

Study on Interaction Energy of PAMAM/Lanthanide（ Ⅲ ） by Molecular Dynamics Method

PAMAM/lanthanide （Ⅲ） nanocomposite was studied by molecular simulation method. Molecular simulation enabled study of the lanthanide tetrad effect at atomic level. However, PAMAM dendrimer exhibiting unique properties such as nanometer size and highly functionalized terminal surface provided a novel space for lanthanide （Ⅲ） to show their peculiar tetrad effect. The results showed that total energies of PAMAM/lanthanide（Ⅲ） nanocomposites presented obvious tetrad effect and special double-double effect. Nd, Gd, and Er fell to the lower point and Gd fell to the lowest point in the TE-Ln curve with four groups. In order to explain the tetrad effect, kinetic energy （KE） and potential energy （PE） were analyzed. The KE curve consisted of three W-type parts （La - Pm, Pm - Tb, Tb - Tm, and the latter two W-type part were axial symmetry） and an exception part （Yb - Lu）. It also showed that the KE of odd atomic number was higher than the even one＇s with exception of Yb and Lu. Furthermore, decomposed potential energies gave out the atomic-level subtle difference of lanthanide which present more regulations for Eu（Ⅲ） - Lu（Ⅲ） compared with La（Ⅲ） - Sm（Ⅲ）. And also Ho-valley and three platforms （Sm - Eu, Td - Dy, Er - Tm） were discovered that refect the regular change of nanocomposite structures. Additionally, there are distinct correlations between Ebond and EInversion, EAngle and EVDW, Eworsion and ECoul, respectively. Therefore, PAMAM could be used in separation of lanthanide by changing conditions.     

树形分子包覆硫化镉量子点的抗老化性能研究

以聚酰胺-胺树形分子为模板制备了平均粒径为2.5nm的CdS量子点, 采用HRTEM、EDS、UV-vis、PL等手段对样品进行表征, 研究了其在室温避光条件下的老化过程. 结果表明, CdS量子点在刚制备的前5d里UV-vis、PL谱峰半峰宽变窄, 发光效率迅速上升, 表明量子点以尺寸窄化生长为主; 5d后UV-vis、PL谱峰半峰宽逐渐宽化, 发光效率缓慢下降, 表明量子点以尺寸宽化(Ostwald 熟化)过程为主. 树形分子的配位作用和模板作用赋予CdS量子点良好的抗老化性能, 6个月后量子点粒径增量<0.3nm, PL强度约降低22%.     

Binding and conformation of dendrimer-based drug delivery systems:a molecular dynamics study

All atomistic molecular dynamics simulations were performed on poly(amidoamine)(PAMAM) dendrimers that compound non-covalently with anticancer drug molecules including DOX,MTX,CE6,and SN38.The binding energies as well as their associated interaction energies and deformation energies were combined to evaluate the relative binding strength among drug,PAMAM,and PEG chains.We find that the deformation of dendrimers due to drug loading plays a crucial role in the drug binding.It is energetically favorable for the drug molecules to bind with PAMAM while the drugs bind with PEG metastable chains via kinetic confinement.Surface PEGylation helps dendrimers to accommodate more drug molecules with greater strength without inducing too much expansion.This work indicates that tuning the functionalized terminal groups of dendrimers is critical to design efficient dendrimer-based drug delivery systems.     

Efficacy of different generations and concentrations of PAMAM–NH2 on the performance and structure of TFC membranes

In this work, several polyamide thin layer membranes were prepared and modified with polyamidoamine (PAMAM) dendrimers in different generations (G₀, G₁, and G₂) and different concentrations (0.5, 1.5 and 3 wt.%) to investigate the occurring changes in the performance and morphology of the prepared thin layers. SEM and AFM data (reinforced with SPM software) proved that the dense and compressed surfaces were fabricated by loading and increasing of the generations and concentrations of PAMAM. In addition, the MWCO of the membranes drastically decreased. The chemical properties of the surface were investigated with ATR-IR and the occurring changes were studied. The zeta potential measurements illustrated that the surface charge of the thin layers was changed with alteration in the generations and concentrations of PAMAM. Additionally, in some cases the rejection capability of NaCl increased over 90%. Furthermore, the contact angle results clearly demonstrated an enhancement in the hydrophilicity of the membranes. The flux recovery ratio of the thin layers increased from 63% (in the unmodified thin layer) to near 97% in the thin layer composed of 3 wt.% G₀.     

一种稠油原油污水处理破乳剂的合成及性能研究

通过保护与反保护的方法,合成了PAMAM稠油原油污水高效破乳剂。探讨了原油废水的pH值、温度,以及不同PAMAM代数对稠油原油污水破乳效果的影响,结果表明,在温度为20℃,pH值的范围为4.8~10.57的条件下,4代PAMAM树形分子投加20mg/L时,除油率达到96.9%。现场试验表明,PAMAM树形分子是一类性能优良的稠油原油污水破乳剂。     

Stimuli-triggered structural engineering of synthetic and biological polymeric assemblies

Response to external stimuli is a fundamental and intrinsic behavior of living systems. There has been increasing interest for designing and constructing responsive polymeric superstructures by self-assembly. Stimuli-induced self-assembly and post-assembly triggering strategies provide an alternative approach for the manipulation of self-assembled architectures of either biological or synthetic polymeric materials. Stimuli-induced structural transformations may produce ensembles with new topologies or materials with exceptionally complex features inaccessible via conventional self-assembly processes. This is in contrast to materials that simply undergo stimuli-induced degradation, or disassembly processes. Since a variety of cellular processes depend on responses to environmental stimuli that lead to more complexity and increased function, and are related to structural transitions over the nano- to microscale, insights into stimuli-triggered morphogenesis can further deepen our understanding of cellular behaviors. Indeed, an understanding of these processes will likely inspire scientists to develop materials with advanced and tailored architectures for biosensing, diagnosis and therapy as well as other biomedical applications. Herein, we highlight state-of-the-art achievements in the stimuli-triggered structural manipulation of polymer assemblies. Furthermore, future developments in this nascent and growing field are briefly discussed.     

微波法制备3．5GPAMAM树状大分子保护的金纳米粒子

以3．5GPAMAM（3．5代聚酰胺一胺型）树状大分子为保护剂，利用微波法还原HAuCl4溶液制备金纳米粒子．考察了当3．5GPAMAM与HAuCl4物质的量的比一定时，微波照射不同时间对金纳米粒子大小及形状的影响；以及同一照射条件下，3．5GPAMAM与HAuCl4不同的物质的量比值对金纳米粒子大小及形状的影响．利用紫外可见分光光度计、透射电子显微镜对其进行了表征．结果表明，当3．5GPAMAM与HauCl4物质的量的比值一定时，金纳米粒子的形状和大小受微波照射时间长短的影响不大；适当延长照射时间，制得的金纳米粒子的分散性较好．在相同照射条件下，随着3．5GPAMAM与HAu—C14物质的量比值的减小，得到的金纳米粒子粒径逐渐变大，且分散性变差．     

Preparation and application of fluorescence dendritic macromolecular nanoparticles

Abstract

In recent years, carbon dots have shown great potential in biological imaging, drug delivery, and other fields. In this study, red fluorescent carbon dots with carboxyl functional groups on the surface were designed and prepared, and the fluorescence properties were studied. At the same time, the carbon dot was combined with dendritic macromolecules, and the aggregate particle size was about 25nm. This combination has good dispersion and stability in both water and methanol, and the DOX-loaded is about 6.72%. The small particle size makes it easy to enter the cells, so as to achieve the function of tumor treatment and cell imaging.