Complex macromolecular architecture design via cyclodextrin host/guest complexes

The design of complex macromolecular architectures has driven macromolecular engineering over the past decades. The introduction of supramolecular chemistry into polymer chemistry provides novel opportunities for the generation of macromolecular architecture with specific functions. Cyclodextrins are attractive design elements as they form supramolecular inclusion complexes with hydrophobic guest molecules in aqueous solution affording the possibility to combine a large variety of building blocks to form novel macromolecular architectures. In the present critical review, the design of a broad range of macromolecular architectures driven by cyclodextrin host/guest chemistry is discussed, including supramolecular block copolymers, polymer brushes, star and branched polymers.     

Developing macromolecular therapeutics: the future drug-of-choice

Macromolecular drugs including peptides, proteins, antibodies, polysaccharides and nucleic acids have been widely used for therapy of major diseases such as carcinoma and AIDS as well as cardiovascular and neurodegenerative disorders among other medical conditions. Due to their unmatched properties of high selectivity and efficiency, macromolecular drugs have been recognized as the drug-of-choice of the future. Since worldwide progress on macromolecular therapeutics still remains in the infant stage and is therefore wide open for equal-ground competition, R&D related to macromolecular drugs should be considered as the main point of focus in China in setting up its strategic plans in pharmaceutical development. In this article, research strategies and drug delivery approaches that should be adopted to enhance the therapeutic effects of macromolecular drugs are reviewed. In addition, comments concerning how to implement such strategies to excel from competition in this challenging research field, such as the design of innovative and highly effective delivery systems of macromolecular drugs with self-owned intellectual property rights, are provided.     

Developing macromolecular therapeutics: the future drug-of-choice

Macromolecular drugs including peptides, proteins, antibodies, polysaccharides and nucleic acids have been widely used for therapy of major diseases such as carcinoma and AIDS as well as cardiovascular and neurodegenerative disorders among other medical conditions. Due to their unmatched properties of high selectivity and efficiency, macromolecular drugs have been recognized as the drug-of-choice of the future. Since worldwide progress on macromolecular therapeutics still remains in the infant stage and is therefore wide open for equal-ground competition, R&;D related to macromolecular drugs should be considered as the main point of focus in China in setting up its strategic plans in pharmaceutical development. In this article, research strategies and drug delivery approaches that should be adopted to enhance the therapeutic effects of macromolecular drugs are reviewed. In addition, comments concerning how to implement such strategies to excel from competition in this challenging research field, such as the design of innovative and highly effective delivery systems of macromolecular drugs with self-owned intellectual property rights, are provided.     

Different composition poly(methyl methacrylate-co-butyl methacrylate) copolymers through seeded semi-batch emulsion polymerization

In the present work the synthesis and the chemical and thermal characterization of poly(methyl methacrylate-co-butyl methacrylate) copolymer, in three different macromolecular compositions, are reported. The aim of the present work was the identification of a standard method to obtain copolymers with controlled macromolecular composition, molecular weights and particle size distribution, together with the identification of the effect of the macromolecular composition on the material properties. A monomer-starved seeded semi-batch emulsion reaction was carried out and optimized, monitoring the kinetic of the copolymerization through the evaluation of residual monomer amounts. Then, an evaluation of the macromolecular composition was performed by Fourier transform infrared spectroscopy analysis. Molecular weight, molecular weight distribution, latex characteristics and thermal behaviour were also investigated.     

The Role of Crowded Physiological Environments in Prion and Prion-like Protein Aggregation

Prion diseases and prion- like protein misfolding diseases are related to the accumulation of abnormal aggregates of the normal host proteins including prion proteins and Tau protein. These proteins possess self-templating and transmissible characteristics. The crowded physiological environments where the aggregation of these amyloidogenic proteins takes place can be imitated in vitro by the addition of macromolecular crowding agents such as inert polysaccharides. In this review, we summarize the aggregation of prion proteins in crowded physiological environments and discuss the role of macromolecular crowding in prion protein aggregation. We also summarize the aggregation of prion- like proteins including human Tau protein, human α-synuclein, and human copper, zinc superoxide dismutase under macromolecular crowding environments and discuss the role of macromolecular crowding in prion- like protein aggregation. The excluded-volume effects caused by macromolecular crowding could accelerate the aggregation of neurodegenerative disease-associated proteins while inhibiting the aggregation of the proteins that are not neurodegenerative disease-associated.     

固定化技术在含酚废水处理中的应用研究进展

本文在汇总国内利用生物固定化技术处理含酚废水研究进展的基础上，认为国内该项技术主要使用物理分隔法中的包埋法。其中采用的包埋材料以天然高分子（如海藻酸钠）和合成高分子（如聚乙烯醇和聚丙烯酰胺）为主，但以用天然高分子改性合成高分子为包埋材料时效果最好。工艺流程多采用三相生物流化床技术，除酚效率可达90％以上，但目前尚未工业化应用。文中分析了各种方法的优缺点，认为目前主要的研究工作应是解决固定化条件对生物活性的影响，提出了今后重点研究的方向是使用光固化技术和新的改性聚合物做包埋材料。     

认识“环境敏感型”生物大分子

生物技术在现代生活中扮演着越来越重要的角色。本文着重分析了＂环境敏感型＂大分子及大分子体系在特定环境条件下发生的一些特定的物理和化学性质的变化机理以及利用控制大分子构象得到对特定外界因素敏感的大分子或大分子体系。目的是认识＂环境敏感型＂大分子或大分子体系在生物技术产品的分离纯化上的具体应用。     

Ultrafiltration of macromolecular solutions with high-flux membranes

Batch and flow recirculation cells were used to study the properties of high-flux ultrafiltration membranes with different macromolecular solutions. At low pressures, solutions of completely retained macromolecular solutes have a flux which is approximately the same as the flux of pure solvent. At higher pressures, the solution flux levels off. The flux, at the leveling-off period, is approximately inversely proportional to the solution concentration. In this plateau region the flux increases with temperature and agitation of the solution but decreases with time. These results are explained by the formation of a gel layer on the membrane surface during the filtration of macromolecular solutions. In ultrafiltration, in contrast to dialysis and GPC, a linear polymer penetrates the selective barrier more readily than does a globular protein of the same molecular weight. The difference may arise from the liquid shear stresses within the barrier medium due to the movement of fluid relative to the pore walls, which is large only in ultrafiltration. Also, retention of polymers was found to decrease with pressure and to increase with agitation of the solution.     

糖蜜酒精废液中大分子焦糖色素模拟物浸出软锰矿的动力学

用收缩芯模型研究了糖蜜酒精废液中大分子焦糖色素在硫酸介质中还原浸出软锰矿的动力学,考察了软锰矿粒度、反应温度、浸出时间、硫酸浓度和焦糖色素浓度对锰浸出速率的影响.结果表明锰浸出速率随反应温度、硫酸浓度、焦糖色素浓度的增加和软锰矿粒径的减小而增加.糖蜜酒精废液中大分子焦糖色素还原浸出软锰矿属固体产物层扩散控制,表观活化能...     

Macromolecular stabilizers for polymers

Inherent chemical activity, physical persistence and good compatibility are factors determining the efficiency of a stabilizer observed during the degradation of amorphous and crystalline synthetic polymers. Synthesis of macromolecular stabilizers is one of the ways used to solve the problem of physical persistency of stabilizers under severe aggressive environmental attacks on polymers. General types of macromolecular stabilizers, routes to their synthesis and characteristic examples of macromolecular antioxidants, UV absorbers, hindered amine light stabilizers, flame retarders and biostabilizers, as well as of polyfunctional systems are given. Problems connected with the use of macromolecular stabilizers are mentioned.     

纳米级CaCO3填充LDPE复合材料的研究

研究了高分子表面处理剂处理纳米CaCO3填充LDPE复合膜的力学性能。结果表明，由于纳米粒子的表面效应以及高分子表面处理剂的作用，加入少量的纳米粒子，复合体系的拉伸强度、断裂伸长率和直角撕裂强度均有不同程度的增加。     

大分子表面改性剂在聚合物表面的富集行为

简述了大分子表面改性剂添加到聚烯烃基体中时接触介质的诱导作用和聚烯烃基体结晶的异质排斥作用及其相对分子质量、链节的柔顺性和与基体的相容性对其表面富集的影响。提出大分子表面改性剂设计合成的基本原则:化学结构和使用环境相匹配、憎水基功能团和亲水基功能团相适应、使用效率和功能持久性相平衡。介绍了大分子表面改性剂合成的主要方法。     

Accounting for Large Amplitude Protein Deformation during in Silico Macromolecular Docking

Rapid progress of theoretical methods and computer calculation resources has turned in silico methods into a conceivable tool to predict the 3D structure of macromolecular assemblages, starting from the structure of their separate elements. Still, some classes of complexes represent a real challenge for macromolecular docking methods. In these complexes, protein parts like loops or domains undergo large amplitude deformations upon association, thus remodeling the surface accessible to the partner protein or DNA. We discuss the problems linked with managing such rearrangements in docking methods and we review strategies that are presently being explored, as well as their limitations and success.     

Liquid–Liquid Phase Separation in the Presence of Macromolecular Crowding and State-dependent Kinetics

Biomolecular condensates formed via liquid–liquid phase separation (LLPS) are increasingly being shown to play major roles in cellular self-organization dynamics in health and disease. It is well established that macromolecular crowding has a profound impact on protein interactions, particularly those that lead to LLPS. Although synthetic crowding agents are used during in vitro LLPS experiments, they are considerably different from the highly crowded nucleo-/cytoplasm and the effects of in vivo crowding remain poorly understood. In this work, we applied computational modeling to investigate the effects of macromolecular crowding on LLPS. To include biologically relevant LLPS dynamics, we extended the conventional Cahn–Hilliard model for phase separation by coupling it to experimentally derived macromolecular crowding dynamics and state-dependent reaction kinetics. Through extensive field-theoretic computer simulations, we show that the inclusion of macromolecular crowding results in late-stage coarsening and the stabilization of relatively smaller condensates. At a high crowding concentration, there is an accelerated growth and late-stage arrest of droplet formation, effectively resulting in anomalous labyrinthine morphologies akin to protein gelation observed in experiments. These results not only elucidate the crowder effects observed in experiments, but also highlight the importance of including state-dependent kinetics in LLPS models, and may help in designing further experiments to probe the intricate roles played by LLPS in self-organization dynamics of cells.     

Mesogen-jacketed liquid crystalline polymers substituted with oligo(oxyethylene) as peripheral chain

Mesogen-jacketed liquid crystalline polymer (MJLCP) is a typical rod-shaped macromolecule. Its unique molecular architecture allows one to tune the geometric parameters of the macromolecular rod. Moreover, the rod surface chemistry can be controlled by designing the peripheral groups of the lateral mesogens. In previous work in this system, short alkyl chains have been used and the resultant macromolecular rods therefore have a hydrophobic surface. In this paper, we report using oligo(oxyethylene) groups as the peripheral groups of the lateral mesogens. Poly{{2,5-bis[4-methoxyoligo(oxyethylene)phenyl]oxycarbonyl}styene} (PnEOPCS) with different oligo(oxyethylene) chain length has been synthesized. These oligo(oxyethylene) groups led to macromolecular rods with hydrophilic surface. Differential scanning calorimetry, polarized light microscopy, and one-/two-dimensional wide-angle X-ray diffraction experiments were carried out to study the phase structures and phase behaviors of this series of polymer. The existence of flexible polar groups lowered the glass transition temperatures of PnEOPCS. All polymers studied showed supramolecular columnar nematic or hexatic columnar nematic phase, which arose from the parallel alignment of the polymer supramolecular rods. The diameter of the cylindrical building block increased with increasing the length of the oligo(oxyethylene) groups. The macromolecular rod surface can be further tuned by complexation the oligo(oxyethylene) with lithium salts. Detailed study showed that this complexation also tremendously affected the liquid crystalline phase of the polymer.     

微波脱硫橡胶的再硫化

考察了微波脱硫橡胶的再硫化历程,并分析了其硫化机理。结果表明,与普通橡胶的硫化不同,微波脱硫橡胶的再硫化历程分为脱硫橡胶中的大分子多硫自由基及大分子环状多硫化物的自交联和添加交联剂对大分子的再交联两个阶段。微波脱硫橡胶的再硫化历程显示了另一个突出的特点即焦烧时间很短,甚至没有焦烧期。     

What Macromolecular Crowding Can Do to a Protein

The intracellular environment represents an extremely crowded milieu, with a limited amount of free water and an almost complete lack of unoccupied space. Obviously, slightly salted aqueous solutions containing low concentrations of a biomolecule of interest are too simplistic to mimic the “real life” situation, where the biomolecule of interest scrambles and wades through the tightly packed crowd. In laboratory practice, such macromolecular crowding is typically mimicked by concentrated solutions of various polymers that serve as model “crowding agents”. Studies under these conditions revealed that macromolecular crowding might affect protein structure, folding, shape, conformational stability, binding of small molecules, enzymatic activity, protein-protein interactions, protein-nucleic acid interactions, and pathological aggregation. The goal of this review is to systematically analyze currently available experimental data on the variety of effects of macromolecular crowding on a protein molecule. The review covers more than 320 papers and therefore represents one of the most comprehensive compendia of the current knowledge in this exciting area.     

Synthesis of poly(vinyl alcohol) combs via MADIX/RAFT polymerization

Poly(vinyl acetate) combs have been prepared via macromolecular design via interchange of xanthate (MADIX)/reversible addition-fragmentation chain-transfer (RAFT) polymerization using xanthate functionalized polymer cores. The comb backbones were prepared using well-defined poly(vinyl alcohol) PVA polymers with a degree of polymerization of 20, 100 and 170, respectively. Functionalization with xanthates via R-group or a Z-group approach resulted in the formation of macromolecular MADIX agents. While Z group designed macromolecular xanthate agents appeared to inhibit the polymerization of vinyl acetate (VAc), R group designed macromolecular xanthate agents achieved to mediate efficiently the bulk polymerization of VAc affording PVAc combs. However, the growth of the combs was accompanied at low conversions by the formation of linear polymer chains as a result of the constant initiation (AIBN) and shoulders, which can be attributed to intermolecular coupling reactions. The proportions of single chains and termination products were observed to increase with the degree of polymerization of the macromolecular MADIX agents broadening the molecular weight distribution. As a result of a stable ester link between the branches and the PVA backbone, the branched PVAc architectures were finally hydrolyzed to afford poly(vinyl alcohol) combs.     

Polymer branching and first normal stress differences in small-amplitude oscillatory shear flow

General rigid bead-rod theory explains polymer viscoelasticity from macromolecular orientation. By means of general rigid bead-rod theory, we relate the normal stress differences of polymeric liquids to the branch position on a backbone branched macromolecule. In this work, we explore the first normal stress differences coefficients of different axisymmetric polymer configurations. When non-dimensionalized with the zero-shear first normal stress difference coefficient, the normal stress differences depend solely on the dimensionless frequency. In this work, in this way, we compare and contrast the normal stress differences of macromolecular chains that are branched. We explore the effects of branch position, length, functionality, spacing, and multiplicity, along a straight chain, in addition to rings and star-shaped macromolecules in small-amplitude oscillatory shear flow.     

中国高分子絮凝剂的研究现状与展望

介绍了无机高分子絮凝剂、有机高分子絮凝剂、微生物絮凝剂、天然高分子絮凝剂和复合高分子絮凝剂的特征及其絮凝机理.认为微生物絮凝剂和天然的高分子絮凝剂是未来高分子絮凝剂的发展方向,同时对我国高分子絮凝剂的市场前景进行了展望.