Hierarchical Structures Based on Two‐Dimensional Nanomaterials for Rechargeable Lithium Batteries

Two‐dimensional (2D) nanomaterials (i.e., graphene and its derivatives, transition metal oxides and transition metal dichalcogenides) are receiving a lot attention in energy storage application because of their unprecedented properties and great diversities. However, their re‐stacking or aggregation during the electrode fabrication process has greatly hindered their further developments and applications in rechargeable lithium batteries. Recently, rationally designed hierarchical structures based on 2D nanomaterials have emerged as promising candidates in rechargeable lithium battery applications. Numerous synthetic strategies have been developed to obtain hierarchical structures and high‐performance energy storage devices based on these hierarchical structure have been realized. This review summarizes the synthesis and characteristics of three styles of hierarchical architecture, namely three‐dimensional (3D) porous network nanostructures, hollow nanostructures and self‐supported nanoarrays, presents the representative applications of hierarchical structured nanomaterials as functional materials for lithium ion batteries, lithium‐sulfur batteries and lithium‐oxygen batteries, meanwhile sheds light particularly on the relationship between structure engineering and improved electrochemical performance; and provides the existing challenges and the perspectives for this fast emerging field.     

A phenyl-salicyliden-imine as a suitable ligand to build functional materials

The synthesis and characterization of 1,4-dicarboxy-phenyl-2-salicyliden-imine (DPSI), a new multi-functional and tridentate ligand, is presented together with the crystal structure of its copper(II) complex. DPSI chemical groups result very attractive because of the straightforward crystal engineering applications, so that we believe this is the first among a wide gamma of materials with promising features and properties.     

DNA水凝胶的制备及应用

脱氧核糖核酸(Deoxyribonucleic acid,DNA)不仅可作为生物遗传的物质基础,又以其可编程性、功能多样性、生物相容性和生物可降解性等优点,在生物材料的构建方面表现出巨大的潜力。DNA水凝胶是一种主要由DNA参与形成的三维网状聚合物材料,同时因其保留的DNA生物性能与自身骨架的机械性能的完美融合使得它成为近年来最受关注的新兴功能高分子材料之一。目前,基于各种功能核酸序列或通过结合不同的功能材料制备的单组分或多组分DNA水凝胶,已广泛用于生物医学、分子检测及环境保护的研究或应用领域中。文中主要总结了近十几年来DNA水凝胶制备方法上的研究进展,探讨了DNA水凝胶的分类策略,并进一步综述了DNA水凝胶在药物运输、生物传感、细胞培养等方面的应用研究。最后对DNA水凝胶未来的发展方向以及可能面临的挑战进行了展望。     

Luminescent magnetic particles: structures, syntheses, multimodal imaging, and analytical applications

Luminescent magnetic particles (LuMaPs) are attractive tools for life science applications such as multimodal imaging, analyte monitoring, nanotherapeutics, and combinations thereof. LuMaPs consist of at least one magnetic and one luminescent component which often are incorporated in a (polymeric) matrix. Alarge variety of materials do exist for the components that make up LuMaPs. However, a smart selection and combination is required for achieving useful tools. While the magnetic component mainly influences the response to a magnetic field, the luminophore can act as label, sensor, or therapeutic agent. The matrix fulfills tasks such as stabilizing the luminophore and magnet, carrying useful functional groups on its surface, or hosting smart drug delivery systems. Surface modifications with targeting ligands can further improve the applicability of LuMaPs, for example in biomedicine. This review provides an overview on LuMaPs with respect to the materials used and to its structures. Routes toward LuMaPs are outlined, and potential applications are discussed.     

Large-scale production of magnetosomes by chemostat culture of <Emphasis Type="Italic">Magnetospirillum gryphiswaldense</Emphasis> at high cell density

Background  

Magnetotactic bacteria have long intrigued researchers because they synthesize intracellular nano-scale (40-100 nm) magnetic particles composed of Fe₃O₄, termed magnetosomes. Current research focuses on the molecular mechanisms of bacterial magnetosome formation and its practical applications in biotechnology and medicine. Practical applications of magnetosomes are based on their ferrimagnetism, nanoscale size, narrow size distribution, dispersal ability, and membrane-bound structure. However, the applications of magnetosomes have not yet been developed commercially, mainly because magnetotactic bacteria are difficult to cultivate and consistent, high yields of magnetosomes have not yet been achieved.     

Processing silk hydrogel and its applications in biomedical materials

This review mainly introduces the types of silk hydrogels, their processing methods, and applications. There are various methods for hydrogel preparation, and many new processes are being developed for various applications. Silk hydrogels can be used in cartilage tissue engineering, drug release materials, 3D scaffolds for cells, and artificial skin, among other applications because of their porous structure and high porosity and the large surface area for growth, migration, adhesion and proliferation of cells that the hydrogels provide. All of these advantages have made silk hydrogels increasingly attractive. In addition, silk hydrogels have wide prospects for application in the field of biomedical materials. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 31:630–640, 2015     

细菌纤维素在生物医学材料中应用的研究进展

细菌纤维素是一种天然的生物高聚物,具有生物活性、生物可降解性、生物适应性,具有独特的物理、化学和机械性能,例如高的结晶度、高的持水性、超细纳米纤维网络、高抗张强度和弹性模量等,因而成为近来国际上新型生物医学材料的研究热点。本文概括了细菌纤维素的性质、研究历史以及在生物医学材料上的应用,重点阐述了细菌纤维素在组织工程支架、人工血管、人工皮肤和治疗皮肤损伤方面的应用以及当前研究现状。     

Recent Development of Quinoxaline Based Polymers/Small Molecules for Organic Photovoltaics

Among the various molecular designs developed for the synthesis of conjugated polymers and small molecules for optoelectronic applications, the donor: acceptor (D–A) approach is the most widely explored method over the past decades. Through the covalent linkage of electron‐rich and electron‐deficient units, a plethora of medium‐low band gap materials has been developed and tested in organic photovoltaic devices. In particular, the quinoxaline aromatic structure and its derivatives are among the most studied electron deficient aromatic units used in D–A structures. Quinoxaline based materials are endowed with characteristics that are useful for large scale production in real world applications, such as easy synthetic procedures and excellent stability in air. Moreover, the use of quinoxaline based polymers/small molecules in bulk heterojunction (BHJ) devices led to power conversion efficiencies over 9%. Considering the potential of quinoxaline based materials, this review gathers together quinoxaline based polymers and small molecules reported in the literature during the last 5 years, summarizing and discussing the structure‐properties relationships for this class of organic semiconductors, aiming to serve as a background and to promote efforts for the further development of new quinoxaline derivatives with improved and advanced properties for future applications.     

Carbonyls: Powerful Organic Materials for Secondary Batteries

The application of organic carbonyl compounds as high performance electrode materials in secondary batteries enables access to metal‐free, low‐cost, environmental friendly, flexible, and functional rechargeable energy storage systems. Organic compounds have so far not received much attention as potential active materials in batteries, mainly because of the success of inorganic materials in both research and commercial applications. However, new requirements in secondary batteries such as flexibility accompanied with low production costs and environmental friendliness, in particular for portable devices, reach the limit of inorganic electrode materials. Organic carbonyl compounds represent the most promising materials to satisfy these needs. Here, recent efforts of the research in the field of organic carbonyl materials for secondary batteries are summarized, and the working principle and the structural design of different groups of carbonyl material is presented. Finally, the influence of conductive additives and binders on the cell performance is closely evaluated for each class of materials.     

第三代测序技术的主要特点及其在病毒基因组研究中的应用

随着基因测序技术的创新和应用,新的高通量测序技术不断涌现,以Pacific Biosciences(PacBio)公司的单分子实时测序(single molecule real time sequencing)为代表的第三代测序(third generation sequencing,TGS)技术开始逐渐应用于基因组研究,包括大型基因组拼装、基因结构变异和表观遗传研究等方面。本文主要对TGS技术的原理、特点和应用,特别是在病毒研究中的应用进行介绍,并与第二代测序(next generation sequencing,NGS)技术进行比较,为基因组测序技术的选择及其临床应用提供一定参考。     

Immobilization of Piromyces rhizinflata β-Glucanase on Poly(Dimethylsiloxane) and Si Wafer and Prediction of Optimum Reaction for Enzyme Activity

EglA, a β-1,4-glucanase isolated from the ruminal fungus Piromyces rhizinflata, shows promise in a wide range of industrial applications because of its broad substrate specificity. In this study, EglA was immobilized on different supporting materials including poly(dimethylsiloxane) (PDMS), Si wafer, textured Si wafer, and indium tin oxide-coated (ITO-coated) glass. The binding abilities of PDMS and Si wafer toward EglA were significantly higher than those of the other supporting materials. The optimized temperature and pH conditions for EglA immobilized on PDMS and on Si wafer were further determined by a response surface methodology (RSM) combined with a central composite design (CCD). The results indicated that the optimum pH and temperature values as well as the specific β-glucanase activity of EglA on PDMS were higher than those of free-form EglA. In addition, EglA immobilized on PDMS could be reused up to six times with detectable enzyme activity, while the enzyme activity of Eg1A on Si wafer was undetectable after three cycles of enzyme reaction. The results demonstrate that PDMS is an attractive supporting material for EglA immobilization and could be developed into an enzyme chip or enzyme tube for potential industrial applications.     

Molecular blending by polymerization of intercalated solvent. Poly(gamma-benzyl-L-glutamate)/benzyl methacrylate as a model system

The aim of the present research is to obtain blending between a polymer and a (polymerized) solvent on the molecular level. Because of its rigid rod structure, poly(gamma-benzyl-L-glutamate) (PBLG) is chosen as the polymer. Benzyl methacrylate (BzMA) has been chosen as the solvent for two reasons. First, the structure of the solvent is very similar to the structure of the side chain of PBLG, favoring interactions between the two materials. Second, the solvent can be polymerized, because of the presence of a C=C bond. In cast films of PBLG and BzMA separate zones of the polymer and solvent are present. Wide-angle X-ray diffraction and Raman results show that upon heating the cast films homogenization occurs and solvent molecules intercalate between the helices of PBLG. At 150 degrees C a hexagonal packing is obtained. The dimensions of the obtained packing depend on the solvent concentration, which confirms that solvent molecules are indeed present within the crystalline lattice. DSC experiments imply that the observed changes upon heating correspond to thermodynamic processes. On cooling the homogeneous samples, disordering of the hexagonal packing occurs. Polymerization of the homogeneous samples results in a disordering of the hexagonal packing and in a contraction of the unit cell. The latter once more confirms that solvent molecules are indeed present within the crystalline lattice. The applied principle of polymerization of a solvent in a molecular homogeneous system can be favorable for many applications, for which morphology control at the molecular level is required.     

Fabrication of three-dimensional collagen scaffold using an inverse mould-leaching process

Natural biopolymers, such as collagen or chitosan, are considered ideal for biomedical scaffolds. However, low processability of the materials has hindered the fabrication of designed pore structures controlled by various solid freeform-fabrication methods. A new technique to fabricate a biomedical three-dimensional collagen scaffold, supplemented with a sacrificial poly(ethylene oxide) mould is proposed. The fabricated collagen scaffold shows a highly porous surface and a three-dimensional structure with high porosity as well as mechanically stable structure. To show its feasibility for biomedical applications, fibroblasts/keratinocytes were co-cultured on the scaffold, and the cell proliferation and cell migration of the scaffold was more favorable than that obtained with a spongy-type collagen scaffold.     

Protein purification by affinity precipitation

Developing the most efficient strategy for the purification of a (recombinant) protein especially at large scale remains a challenge. A typical problem of the downstream process of mammalian cell products is, for instance, the early capture of the highly diluted product from the complex process stream. Affinity precipitation has been suggested in this context. The technique is known for over 20 years, but has recently received more attention due to the development of new materials for its implementation, but also because it seems ideally suited to specific product capture at large scale. The present review gives a comprehensive overview over this technique. Besides an introduction to the basic principle and a brief summary of the historical development, the main focus is on the current state-of-art of the technique, the available materials, important recent applications, as well as process design strategies and operating procedures. Special consideration is given to affinity precipitation for product recovery at large scale.     

Enzyme stabilization by nano/microsized hybrid materials

Immobilization is a key technology for successful realization of enzyme‐based industrial processes, particularly for production of green and sustainable energy or chemicals from biomass‐derived catalytic conversion. Different methods to immobilize enzymes are critically reviewed. In principle, enzymes are immobilized via three major routes (i) binding to a support, (ii) encapsulation or entrapment, or (iii) cross‐linking (carrier free). As a result, immobilizing enzymes on certain supports can enhance storage and operational stability. In addition, recent breakthroughs in nano and hybrid technology have made various materials more affordable hosts for enzyme immobilization. This review discusses different approaches to improve enzyme stability in various materials such as nanoparticles, nanofibers, mesoporous materials, sol–gel silica, and alginate‐based microspheres. The advantages of stabilized enzyme systems are from its simple separation and ease recovery for reuse, while maintaining activity and selectivity. This review also considers the latest studies conducted on different enzymes immobilized on various support materials with immense potential for biosensor, antibiotic production, food industry, biodiesel production, and bioremediation, because stabilized enzyme systems are expected to be environmental friendly, inexpensive, and easy to use for enzyme‐based industrial applications.     

Jellyfish mucin (qniumucin) extracted with a modified protocol indicated its existence as a constituent of the extracellular matrix

Jellyfish (JF) mucin (precisely, a mucin-type glycoprotein named qniumucin: Q-mucin) first discovered in JF is mainly composed of highly O-glycosylated domains, and its unique structure suggests its wide applications as a smart material. In this study, the standard protocol used to date was thoroughly reinvestigated because the processing of raw JF was rather difficult and continuous production from frozen sources was also indispensable. Finally, we concluded that Q-mucin is involved not in mucus but in the mesoglea, i.e., the extracellular matrix (ECM), as a part of a very large polymer complex. We added a treatment procedure with a chelate reagent (e.g. EDTA) to inactivate endogenous proteases that induce the spontaneous decomposition of the collagens in ECM. The amino acid composition (AAC) of each precipitate formed upon EtOH addition indicated that Q-mucin dissociates from the biopolymer complex as a constituent highly soluble in deionized water. Since the remaining portion of ECM still seemed to contain a large amount of the precursor of Q-mucin even after the extraction with water is completed, the yield of Q-mucin is expected to increase markedly if an innovative method to decompose EtOH precipitates is developed. The existence of Q-mucin in ECM seems to be described in parallel with that of proteoglycans (PG) in mammalian cartilage because they resemble each other.     

An overview of the biophysical applications of atomic force microscopy

The potentialities of the atomic force microscopy (AFM) make it a tool of undeniable value for the study of biologically relevant samples. AFM is progressively becoming a usual benchtop technique. In average, more than one paper is published every day on AFM biological applications. This figure overcomes materials science applications, showing that 17 years after its invention, AFM has completely crossed the limits of its traditional areas of application. Its potential to image the structure of biomolecules or bio-surfaces with molecular or even sub-molecular resolution, study samples under physiological conditions (which allows to follow in situ the real time dynamics of some biological events), measure local chemical, physical and mechanical properties of a sample and manipulate single molecules should be emphasized.     

半乳甘露聚糖胶酶法改性研究进展

由于半乳甘露聚糖的水溶液在低浓度下仍具高黏性以及它的凝胶性质,因此在工业上具有很多重要的应用。半乳甘露聚糖聚糖的酶法改性主要包括脱去支链和切断主链两种方式。相对于化学改性来说,酶法改性具有易控制、反应条件温和等很多优点,因此成为改变半乳甘露聚糖分子结构以获得所需特性的最具潜力的改性方法。α－半乳糖苷酶和 β－甘露聚糖酶是半乳甘露聚糖改性和水解中最常用的酶。简要介绍了有关这两种酶的来源和新型制备菌株的近期研究概况。在医药和食品等工业中,酶法改性后的半乳甘露聚糖具有很广阔的应用前景。     

Recent Developments in Using Advanced Sequencing Technologies for the Genomic Studies of Lignin and Cellulose Degrading Microorganisms

Lignin is a complex polyphenyl aromatic compound which exists in tight associations with cellulose and hemicellulose to form plant primary and secondary cell wall. Lignocellulose is an abundant renewable biomaterial present on the earth. It has gained much attention in the scientific community in recent years because of its potential applications in bio-based industries. Microbial degradation of lignocellulose polymers was well studied in wood decaying fungi. Based on the plant materials they degrade these fungi were classified as white rot, brown rot and soft rot. However, some groups of bacteria belonging to the actinomycetes, α-proteobacteria and β-proteobacteria were also found to be efficient in degrading lignocellulosic biomass but not well understood unlike the fungi. In this review we focus on recent advancements deployed for finding and understanding the lignocellulose degradation by microorganisms. Conventional molecular methods like sequencing 16s rRNA and Inter Transcribed Spacer (ITS) regions were used for identification and classification of microbes. Recent progression in genomics mainly next generation sequencing technologies made the whole genome sequencing of microbes possible in a great ease. The whole genome sequence studies reveals high quality information about genes and canonical pathways involved in the lignin and other cell wall components degradation.     

Tunable Plasmon-Induced Transparency of Double Continuous Metal Films Sandwiched with a Plasmonic Array

Making a continuous metal film with near-unity transparency has received more and more attention in recent years because of its potential applications for various optoelectronic devices. Here, we theoretically show that a high tunable plasmon-induced transparency metal film structure can be performed by double continuous metal films inserted with a two-dimensional hexagonal lattice array of plasmonic nanopariticles. The proposed structure shows near-unity anti-reflection and intensively enhanced transmission via the cooperative effects of strong resonant near-field light input and output coupling by the plasmonic array and the excitation of surface electromagnetic waves of the metal films. The optical response can be efficiently mediated by varying the sizes of nanoparticles and the separated distance between the metal array and the metal films. With the merits of high transparency, sub-wavelength sizes and wholly retained metal characteristics including high conductivity via using the pure metallic materials, the structure proposed here suggests various potential applications in optoelectronic integrated circuits.