Current advances in the non‐chromatographic fractionation and characterization of PEGylated proteins

For more than 30 years, PEGylation has been used to improve the physicochemical properties of several proteins and therapeutic drugs having a major impact in the biopharmaceutical industry. The purification of PEGylated proteins usually involves two basic challenges: (1) the separation of PEG‐proteins from other reaction products; and (2) the sub‐fractionation of PEG‐proteins on the basis of their degree of PEGylation and positional isomerism. Currently, most PEGylated protein purification processes are based on chromatographic techniques, especially size exclusion chromatography (SEC) and ion exchange chromatography (IEX). Nonetheless, other less frequently used strategies based on non‐chromatographic techniques such as ultrafiltration, electrophoresis, capillary electrophoresis, and aqueous two‐phase systems have been developed in order to fractionate and analyze PEGylated derivates. This review presents current advances in some of the most widely used non‐chromatographic strategies for the fractionation and analysis of PEG‐protein conjugates. Copyright © 2010 Society of Chemical Industry     

生物活性天然产物分离技术的研究进展(英文)

Bioactive natural products are a main source of new drugs, functional foods and food additives. The separation of bioactive natural products plays an important role in transformation and use of biomass. The isolation and purification of bioactive_principle from a complex matrix is often inherent bottleneck for the utilization of natural products, so a series of extraction and separation techniques have been developed. This review covers recent advances in the separation of bioactive natural products with an emphasis on their solubility and diffusion coefficients, recent extraction techniques and isolation techniques. This overview of recent technological advances, dis- cussion of pertinent problems and prospect of current methodologies in the separation of bioactive natural products may provide a driving force for development of novel separation techniques.     

互穿网络聚合物水凝胶的制备及其吸附研究进展

互穿网络聚合物(IPN)水凝胶在分离技术领域具有广泛的应用前景,这些年受到人们广泛关注.本文介绍了聚多糖基(壳聚糖、海藻酸、淀粉和其他聚多糖)、蛋白质基(明胶、胶原蛋白、丝纤蛋白和大豆蛋白)和合成聚合物基(非离子型和离子型)IPN水凝胶的制备方法,主要包括同步-IPN、分步-IPN和半-IPN的制备方法.为了提高聚合物水凝胶的生物相容性、溶胀率和机械强度,采用天然高分子与合成高分子共混制备IPN水凝胶.与单网络水凝胶相比,IPN水凝胶对染料和重金属离子的吸附速率快、吸附容量大.为了达到选择性吸附和提高水凝胶的比表面积,制备离子印迹IPN水凝胶和多孔IPN复合冷冻凝胶,是未来研究高效吸附IPN水凝胶的发展方向之一.     

Automated affinity separation processes

This paper describes the automation of fixed-bed affinity separation techniques for the purification of proteins. The basic requirements of an automated system suitable for carrying out such a separation are detailed together with an introduction to the concept of process optimisation by interactive control. Such systems can continue to optimise separations when operating conditions are variable but require that methods for the on-line analysis of separation performance are available. Such methods require that the levels of particular proteins in the presence of other proteins can be determined and include continuous measurement of enzyme activity and the use of the new technique of rapid chromatographic analysis. The latter technique, which can also be used more generally in the process control of protein purification, is described and its use illustrated.     

Simplified preparation of low polydispersity,low molecular weight poly(D,L‐lactic acid) by liquid/liquid phase separation for drug delivery systems with discussion of molecular weight characterization

Poly(D ,L ‐lactic acid) (PLA) has been widely used in pharmaceutics and medicine. Low molecular weight (LMW) PLA is especially useful for rapidly degrading biomaterials such as those used for short‐duration drug delivery systems. There is scant information available in the literature regarding the purification and analysis of LMW PLA. In this paper we report (1) a convenient and effective polymer purification/fractionation technique to produce LMW PLA with narrow molecular weight distribution (MWD) and (2) analyses that were used to characterize the molecular weight and MWD of these polymers. A novel, convenient and effective temperature‐induced solution‐phase separation method was developed to produce narrow MWD, LMW (600–2000 g mol^?1) PLA. Molecular weights determined using gel permeation chromatography (GPC) with universal calibration, unlike those determined with the commonly used conventional calibration, showed good agreement with those obtained using several independent direct techniques. The phase separation induced by temperature reduction of a polymer in a single solvent system provided a simple and effective technique to produce narrow MWD, LMW PLA polymers. Additional advantages of this technique are: (1) only one solvent is required; (2) the risk of local complete solid polymer precipitation is eliminated; (3) it is reversible and not dependent on the rate of cooling; and (4) use of chlorinated solvents is avoided. This technology may open up a new opportunity for manufacturing LMW polymers with narrow MWD. We also found that GPC with universal calibration is a more accurate method than GPC with the commonly used conventional calibration for characterizing these polymers, and is straightforward to use especially now that on‐line viscosity detectors are widely available. Copyright © 2010 Society of Chemical Industry     

Verfahren zum Sichtbarmachen von Gasströmungen

Techniques for the visualization of gas flow . Flow processes with separation on surfaces of any shape can be calculated only in isolated cases. Thus, owing to the considerable technical and economic significance of flow processes particular importance attaches to techniques for their visualization as well as for their measurement. The complex variety of flow processes on flow past or through objects requires simple fast methods usable without any great amount of know-how. Most flow visualization techniques are based on basic process engineering processes. These techniques are surveyed, as they apply to incompressible gas flow. They can be divided into three categories, depending upon whether the entire flow field, the flow adjacent to the boundary layer, or the effects of flow processes on a solid wall (wall effects) are to be visualized. Significant advances have been made in techniques for the visualization of wall effects, which are reported here.     

General Survey of Adsorptive Bubble Separation Processes

Abstract

In this article we present a general survey of adsorptive bubble separation processes. These separation methods involve the use of selective adsorption at gas-liquid interfaces, the interfaces being generated by gas bubbles in aqueous media. A variety of processes based on this mechanism have been developed, and these methods are described in this review. The underlying concepts in this field are then explored so that the similarities between the methods can be seen. Engineering applications, as well as our own work on analytical applications, are presented. Suggestions are also made as to future potentialities for these adsorptive bubble separation processes. Finally, to place these methods in proper perspective, the techniques are compared to such widely used processes as ion exchange and liquid-liquid extraction.     

Matrimid® 5218 in preparation of membranes for gas separation: Current state-of-the-art

Over the last decades, different polymers have been used as continuous phase for preparing selective membranes for gas separation. Today, some of these materials have been consolidated commercially; however, the necessity to improve the performance (in terms of permeability/selectivity) of polymeric membranes above Robeson’s upper bound has been conducted by blending polymers, use of additives, implementation new methods, development of new materials, coating films, development of mixed matrix membranes, and so on. One of the most recent approaches is the use of polymers such as polyimides, i.e., Matrimid® 5218, which has demonstrated, to provide remarkable gas separation performance using the attempts aforementioned. The aim of this work is to present the current state-of-the-art of the use of Matrimid® 5218 in preparation of membrane for gas separation. The progress in this field is summarized and discussed chronologically in two periods, decade (from 1998 to 2008) and current (from 2009 up to now) frameworks. This contribution leads to take a complete and compelling overview of the state-of-the-art based on Matrimid. Furthermore, the main approaches, aim of study, gas separation evaluated, main techniques used for membrane characterization, main supplier of the polymer, main secondary materials for blending, fillers incorporated into the matrix, and remark of the study are summarized in detail. Finally, it denotes the prospects and future trends on use of Matrimid® 5218 for membrane applications.     

固体酸催化单糖制备5-羟甲基糠醛(5-HMF)的研究进展

固体酸近年来被广泛应用于有机合成、催化等领域,具有易于和产物分离、可回收、不腐蚀设备等优点。5-HMF是一种重要的有机中间体,可以作为合成新型高聚物、医药中间体、燃料的原材料,应用固体酸催化糖类生物质制备5-HMF是当前研究的热点之一。综述了固体酸催化单糖制备5-HMF的研究进展,并对固体酸催化单糖制备5-HMF存在的问题和未来的发展方向进行了总结和展望。     

Tuning Gas-Diffusion through Dynameric Membranes: Toward Rubbery Organic Frameworks (ROFs)

Obtaining high permeability whilst keeping a reasonable selectivity is the most important challenge in the development of membrane systems for gas separation. Satisfactory performance is usually obtained with polymeric membranes through which gas transport is controlled by gas-diffusivity in glassy polymers and by gas-solubility in rubbery polymers. During the last decade, important advances in this field have been made possible by molecular control of gas separation properties. The combination or replacement of classical glassy polymers with metal-organic crystalline frameworks (crystalline MOFs), such as zeolitic imidazolate frameworks (ZIFs) or other zeolites, provides reasonable permeability through the porous networks formed, and high selectivity, due to so-called ‘selectivity centers’, which interact specifically with the gas molecules. Despite impressive progress, difficulties in obtaining homogeneous, mechanically stable, thin layer MOFs on various supports have been encountered. Given the observed high permeabilities of rubbery polymers and their flexible casting properties, it should be very interesting to build rubbery organic frameworks (ROFs), as alternative materials for gas membrane separation systems. Here we use low macromolecular constituents and dialdehyde core connectors, in order to constitutionally generate ROFs. Distinct from rubbery polymeric membranes, the performance of the ROFs depends univocally on diffusional behaviors of gas molecules through the network. For all gases, a precise molecular composition of linear and star-type macromonomers generates an optimal free volume for a maximal diffusion through the matrix. These results should initiate new interdisciplinary discussions about highly competitive systems for gas separation, which are constitutionally controlled on a molecular scale.     

Unleashing the potential of supercritical fluids for polymer processing in tissue engineering and regenerative medicine

One of the major scientific challenges that tissue engineering and regenerative medicine (TERM) faces to move from benchtop to bedside regards biomaterials development, despite the latest advances in polymer processing technologies.A variety of scaffolds processing techniques have been developed and include solvent casting and particles leaching, compression molding and particle leaching, thermally induced phase separation, rapid prototyping, among others. Supercritical fluids appear as an interesting alternative to the conventional methods for processing biopolymers as they do not require the use of large amounts of organic solvents and the processes can be conducted at mild temperatures. However, this processing technique has only recently started to receive more attention from researchers. Different processing methods based on the use of supercritical carbon dioxide have been proposed for the creation of novel architectures based on natural and synthetic polymers and these will be unleashed in this paper.     

苯乳酸的微生物合成及分离研究进展

苯乳酸是一种高值有机酸和新型的天然防腐剂,可由乳酸菌等多种微生物代谢产生。苯乳酸有着较为宽广的抑菌谱,对大多数革兰氏阳性、阴性菌和真菌都有明显的抑菌作用,不仅作为天然抑菌剂可替代化学合成的防腐剂,而且可经聚合反应合成聚苯乳酸新型高分子材料,作为聚乳酸高分子的替代物。因此,苯乳酸在化工、制药、生物、材料和食品等领域有广阔的应用前景。本文从苯乳酸抑菌特性、微生物菌株、转化合成、代谢途径及下游分离纯化等方面,简述了其生物转化合成和分离的研究现状。微生物菌株是苯乳酸合成的关键,基因工程菌的转化能力虽然高效,但构建工程菌较复杂;从自然环境中筛选安全优良的菌株,可以简化转化合成过程,提高转化率和料液中苯乳酸的浓度;苯乳酸的分离纯化还处于实验室的规模,有待进一步探索以达到工业化的要求。     

天然产物分离新技术

对天然产物的提取方法和分离精制方法进行了综述。对天然产物的提取方法如双水相萃取、超l临界萃取、微波提取、超声波提取和液膜提取等进行了论述，并对分子精馏、大孔吸附树脂、凝胶色谱和分子印迹等技术在天然产物分离精制上的应用进行了介绍。对各种方法的特点和不足进行了比较。     

聚合物-金属有机框架材料的研究进展

金属有机框架（MOFs）因其大孔隙率、高比表面积和规则可调的孔径结构等优势受到了广泛关注,然而该材料较差的热塑性和力学性能限制了其可加工性,不利于大规模工业应用。为解决此问题,研究者们将聚合物作为多孔材料的一部分,通过直接或间接的方法合成了一种三维且高度多孔的材料——聚合物-金属有机框架（polymer-metal-organic frameworks, polyMOFs）。此材料兼具MOFs出色的性能与聚合物的可加工性,在气体分离、生物医用和催化等领域具有广阔的应用前景。本文综述了polyMOFs的三种合成方法,包括合成后聚合、单晶到单晶转换和直接合成法,介绍了三种方法的特点与不足,并展望了未来polyMOFs的发展方向。     

微生物酶分离纯化研究进展

在对常规的微生物酶分离纯化方法如沉淀法、疏水层析、凝胶过滤、离子交换层析及亲和层析等的特点、原理及应用进行介绍的基础上,概述了膜处理技术、免疫纯化技术、双水相体系萃取等新颖微生物酶分离纯化技术。指出常规方法和新颖方法的结合为微生物酶带来了高效的分离纯化效果,开发先进、灵活的蛋白质化学技术分离纯化天然酶、重组酶、人工模拟酶及杂合酶势在必行。     

Magnetic separations: From steel plants to biotechnology

Magnetic separations have for decades been essential processes in diverse industries ranging from steel production to coal desulfurization. In such settings magnetic fields are used in continuous flow processes as filters to remove magnetic impurities. High gradient magnetic separation (HGMS) has found even broader use in wastewater treatment and food processing. Batch scale magnetic separations are also relevant in industry, particularly biotechnology where fixed magnetic separators are used to purify complex mixtures for protein isolation, cell separation, drug delivery, and biocatalysis. In this review, we introduce the basic concepts behind magnetic separations and summarize a few examples of its large scale application. HGMS systems and batch systems for magnetic separations have been developed largely in parallel by different communities. However, in this work we compare and contrast each approach so that investigators can approach both key areas. Finally, we discuss how new advances in magnetic materials, particularly on the nanoscale, as well as magnetic filter design offer new opportunities for industries that have challenging separation problems.     

Separation of light hydrocarbons with ionic liquids: A review

Light hydrocarbons(C_1–C_4) are fundamental raw materials in the petroleum and chemical industry. Separation and purification of structurally similar paraffin/olefin/alkyne mixtures are important for the production of highpurity or even polymer-grade light hydrocarbons. However, traditional methods such as cryogenic distillation and solvent absorption are energy-intensive and environmentally unfriendly processes. Ionic liquids(ILs) as a new alternative to organic solvents have been proposed as promising green media for light hydrocarbon separation due to their unique tunable structures and physicochemical properties resulting from the variations of the cations and anions such as low volatility, high thermal stability, large liquidus range, good miscibility with light hydrocarbons, excellent molecular recognition ability and adjustable hydrophylicity/hydrophobicity. In this review, the recent progresses on the light hydrocarbon separation using ILs are summarized, and some parameters of ILs that influence the separation performance are discussed.     

Updates on biogas enrichment and purification methods: A review

The market for biogas production has been increasing every year all over the world. The use of biogas as an energy vector is accomplished through the most diverse applications, such as direct burning (thermal energy), internal combustion engines, and fuel cells. Besides direct applications, biogas can be used as a raw material for producing high added-value products, such as molecular hydrogen and renewable hydrocarbons, through a new enterprise concept, the biorefineries. Purity and quality control are determinant factors that enable the decision-making regarding the end use of biogas. Physical, chemical, and biological methods can be used in biogas upgrading processes as well as a combination of different techniques. This review aims to deepen the knowledge about relevant technologies for biogas purification. It also addresses the most efficient and feasible methods, challenges to be overcome, and main demands for future studies. Therefore, the presentation, in a detailed way, of the synergistic effects caused by components contained in natural biogas and the combinatorial methods for removing these contaminants, differentiates this from other works that approach only the purification techniques but do not point out their problems and causes more comprehensively. Thus, studies related to the combined effects of contaminants would be interesting in future works.     

Recent advances in molecularly imprinted polymers in food analysis

Food security as a world issue has received increasing concern, and therefore, effective analytical methods and technologies have been continuously developed. However, the matrix complexity of food samples and the trace/ultratrace presence of targeted analytes require highly efficient cleanup and enrichment materials and procedures. Molecularly imprinted polymers (MIPs) with specific recognition abilities as versatile materials are being increasingly developed for diverse species in various fields, especially in food analysis. In this review, we mainly summarize the recent advances in MIPs used for food matrices over the last 5 years. We focus on toxic and harmful substances, such as pesticide/drug residues, heavy metals, microbial toxins, and additives. Some relatively new preparation methods involving surface imprinting, composites, and stimuli responsiveness are reviewed. Different MIPs as solid‐phase adsorbents in solid‐phase extraction, solid‐phase microextraction, matrix solid‐phase dispersion, stirring bar sorptive extraction, and magnetic material extraction and as stationary phases in chromatographic separation for foodstuff have been comprehensively summarized. MIP‐based biomimetic sensing and enzymelike catalysis receive special attention. Moreover, some limitations and comparisons related to MIPs performances are also discussed. Finally, some significant attempts to further promote MIP properties and applications to ensure food safety are discussed. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40766.     

Polymers for the industrial water user

This paper deals with the roles played by synthetic polymers in industrial water treatment practice. Other contributors have covered the use of polymers in such fields as water purification, sewage treatment and mineral separation, and this contribution is mainly confined to the use of polymers in boiler feed water and cooling water treatment.