自组装技术及其在生物传感器中的应用研究

构造高度有序性和重复性的生物分子薄膜是提高生物传感器检测性能的关键,自组装膜以其原位自发形成、热力学稳定、制作方便简单、对基底材料形状要求低、可人为地通过合成来设计分子结构和进行分子剪裁等特点,应用于构筑电化学酶传感器,引起了广泛的关注。分析了自组装膜形成的原理,介绍了自组装技术在电极表面固定酶的方法,综述了自组装技术在生物传感器中的应用,展望了自组装技术应用的发展趋势。     

影响多步脱氢酶CrtI功能的关键结构特征探索

在生物体内存在可催化多步连续反应的通用酶,对生物代谢过程具有重要作用。八氢番茄红素脱氢酶（CrtI）作为典型代表,可以催化多步连续脱氢反应,生成番茄红素等具有重要价值的产物。本文以酿酒酵母为底盘研究CrtI的催化功能特征。首先通过组合设计与筛选番茄红素合成路径中的三种外源酶CrtE、CrtB和CrtI,发现CrtI是主要的限制因素,且三孢布拉氏霉菌来源的CrtI(BtCrtI)表现出优异的催化功能。通过生物信息学与蛋白结构分析发现BtCrtI的S311残基是连接和稳定活性中心结构的关键。随后通过分析该位点的饱和突变结果,揭示了该位点的氨基酸残基类型对活性中心结构和功能的显著作用,为酶的设计和改造提供了新的思路。同时发现CrtI的活性差异未对合成路径中的类胡萝卜素的代谢流造成扰动,表明CrtI是番茄红素的产量和纯度的决定因素。     

真核来源的抗菌肽及其在食品中的应用

抗菌肽是生物防御系统产生的一类对抗外源病原体的多肽,具有抑菌谱广,热稳定性好等特点,在"从农场到餐桌"的整个食物链中有广阔的应用前景,本文介绍了真核来源抗菌肽的生物学特性及在不同食品中的应用。     

碳纤维增强聚合物组织工程支架的制备及表征

以碳纤维（CF）作为增强材料,将CF有序排列于聚乳酸羟基乙酸（PLGA）多孔结构中,制备性能优良的CF/PLGA复合支架,并对其力学性能及细胞生物学性能进行表征.对增强体CF进行有序排列以提高支架的力学性能,扫描电子显微镜（SEM）观察CF/PLGA复合支架的微观形貌,可以看出CF在聚合物基体内部是呈有序结构并且二者结合情况良好.为了提高CF的生物相容性,利用对氨基苯甲酸对CF进行表面修饰,细胞生长在支架上的SEM照片反映了成纤维细胞对PLGA及CF/PLGA复合支架的黏附性能良好;通过细胞毒性测试,发现表面修饰的CF对细胞的生长没有负面作用,且在一定程度上促进了细胞的生长.研究结果表明,制备的CF/PLGA支架具有良好的力学性能和生物相容性,在骨组织工程支架的应用中具有一定的潜力.     

基于外源供氢沼气生物提纯微生物及反应器开发研究进展

利用外源氢气作为电子供体对沼气进行厌氧生物提纯,具有反应条件温和、副产物少等优点,是当前国内外研究的热点。气液传质效率低是该技术发展的最大阻力,厌氧生物反应器影响耗氢产甲烷菌的生长和分布、反应底物的接触方式和接触时间,进而影响运行的稳定性和处理效果,是目前提高反应效率的研究重点。本文通过介绍基于外源供氢的沼气生物提纯原理、微生物分布的基本特征和提纯系统运行操作方式,对反应过程中反应器的主要要求进行了分析;系统综述了目前基于外源氢气的沼气生物提纯工艺中连续搅拌式反应器（CSTR）、上流式污泥反应器（UASB）和生物附着式反应器的应用研究进展,总结了基于外源氢气的沼气生物提纯技术的发展现状和各类反应器的特性,并从传质研究方法和氢气来源等方面提出了建议与展望。     

合成生物学研究进展

合成生物学是以工程化设计思路,构建标准化的元器件和模块,改造已存在的天然系统或者从头合成全新的人工生命体系,实现在化学品合成(包括材料、能源和天然化合物)、医学、农业、环境等领域的应用。人们利用基本的生物学元件设计和构建了基因开关、振荡器、放大器、逻辑门、计数器等合成器件,实现对生命系统的重新编程并执行特殊功能。模块化处理生物的代谢途径,并在底盘细胞上进行组装和优化,可以实现大宗化学品和精细化学品的合成。目前人们已经在丁醇、异丁醇、青蒿素和紫杉醇等化合物的生物合成上取得了重要进展。近年来还发展了多种基因组编辑和组装技术,可精确地对基因组进行编辑,人们还成功地合成了噬菌体基因组、支原体基因组和酵母基因组。在未来的50～100年内,合成生物学将对人类的医疗、化学品制造(含药品)、军事产生渐进性的、渗透性的但颠覆性的意义。     

中煤北京煤矿机械有限责任公司采用PTC PRO／ENGINEER提高整体设计分析能力

1月10日，中煤北京煤矿机械有限责任公司（以下简称“北京煤机”）已经在液压支架产品设计和制造中采用Pro／ENGINEER技术。该技术是PTC提供的一种整合CAD／CAM／CAE解决方案，可以帮助企业实现精密、直观和逼真的数字产品展现方式。Pro／ENGINEER的全面应用使北京煤机在自顶向下的模块分析应用设计方面取得了重大的进步，保持了产品支架设计制造水平位居国内一流的领先地位。     

环境响应型共聚物自组装的研究进展

环境响应型聚合物是近年来受到广泛关注的功能材料,这种类型的共聚物可以对外部环境刺激而产生相应的结构,物理和化学变化。根据外部环境刺激反应的机理和类型的不同,分为单刺激响应与多重刺激响应。本文重点讨论关于环境响应型共聚物的设计,合成,自组装和应用的研究现状,总结说明了当受到pH,温度,光照,CO_2,氧化还原剂等外部环境刺激时各类有序聚集体所表现的变化,展望了智能嵌段共聚物在药物控释,纳米容器制备和生物功能材料中的潜在应用价值和未来的发展方向。     

基于酶和无机/金属纳米颗粒组装的生物复合催化剂

综述了具有生物兼容性的无机/金属纳米颗粒和酶组装成生物复合催化剂的最新进展,并从纳米材料的自身特性出发,分析了酶和无机/金属纳米颗粒组装的多种方法以及纳米粒子在多个方面对酶催化效率的影响,进而归纳了纳米颗粒对酶具有的多种纳米载体效应.最后探讨并展望了利用酶和无机/金属纳米颗粒的组装将天然酶改造成更高效的复合生物催化剂的研究现状与前景.     

酶/MOFs复合材料催化性能调控及应用

金属有机框架（MOFs）具有比表面积大、设计性强和生物相容性好等优良特性，可以作为固定化酶的理想载体，从而提高游离酶的稳定性和催化性能，许多酶/MOFs复合材料也显示出比游离酶更好的催化性能。因此，酶/MOFs复合材料已应用于生物传感、检测、催化等领域，已成为传统催化剂的环保替代品。综述了酶在MOFs上的3种固定化方法（表面固定、孔封装和原位包埋法），重点介绍了4种影响酶/MOFs复合材料催化性能的因素及调控方法，对酶/MOFs复合材料在催化方面的应用也进行了总结，并对酶固定化的未来进行了展望。     

Hybrid Nanoreactors: Coupling Enzymes and Small-Molecule Catalysts within Virus-Like Particles

Virus-like particles (VLPs) provide unique scaffolds for the construction of coupled catalytic systems by attachment and encapsulation of catalysts within their hollow interiors. The interior of VLPs provides an environment where catalysts of biological or synthetic origins can be confined, protected, and colocalized in close proximity with catalysts of different types. Herein, we utilize the P22VLP as a scaffold to construct a synthetic hybrid catalyst by attachment of a small organometallic catalyst to the interior colocalized with an encapsulated enzyme. This produces a complex and active coupled biomimetic catalyst system. By combining both enzymatic and synthetic catalysts together, new biological synthetic hybrid materials can be produced that incorporate the best of both catalytic systems.     

Polymers used to influence cell fate in 3D geometry: New trends

The extracellular matrix (ECM) is a hydrogel-like structure comprised of several different biopolymers, encompassing a wide range of biological, chemical, and mechanical properties. The composition, organization, and assembly of the ECM play a critical role in cell function. Cellular behavior is guided by interactions that occur between cells and their local microenvironment, and this interrelationship plays a significant role in determining physiological functions. Bioengineering approaches have been developed to mimic native tissue microenvironments by fabricating novel bioactive hydrogel scaffolds. This review explores material designs and fabrication approaches that are guiding the design of hydrogels as tissue engineered scaffolds. As the fundamental biology of the cellular microenvironment is often the inspiration for material design, the review focuses on modifications to control bioactive cues such as adhesion molecules and growth factors, and summarizes the current applications of biomimetic scaffolds that have been used in vitro as well as in vivo.     

Cells integration onto scaffolds prepared from polyester based polymers – importance of polymer thermal properties in addition to hydrophilicity

Abstract

Three-dimensional (3D) scaffolds represent valuable tools for biological studies and tissue engineering applications. They offer better biological environment that better mimic 3?D dynamic in vivo conditions compared with conventional bidimentional (2D) cell culture systems. The integration of cells within the scaffolds is, however, dependent on their properties. In the present study, porous scaffolds were prepared from poly lactide (PLA), poly lactide polyethylene glycol copolymer (PLA-PEG) and poly lactide-co-glycolide – polyethylene glycol copolymer (PLGA-PEG) using porogen leaching method with NaCl particles as porogen. The three scaffolds were prepared with identical conditions (concentration, dimensions, porogen weight fraction and particle size) in order to evaluate the impact of polymer composition and properties on scaffold characteristics (internal architecture and pores distribution), as well as fibroblasts integration and proliferation within the scaffold 3?D network. The impact of hydrophilicity, water uptake and protein adsorption are discussed. The data shows that amorphous polymers, which have glass transition temperature close to cell culture temperature, may be advantageous for scaffold construction and cell integration. This fact needs to be considered when interpreting data of cell interaction with scaffolds obtained using amorphous polymers developed for 3?D cell culture and tissue engineering applications.     

G‐Quadruplexes as Tools for Synthetic Biology

With the potential to engineer biological systems, synthetic biology is an emerging field that combines various disciplines of sciences. It encompasses combinations of DNA, RNA and protein modules for constructing desired systems and the “rewiring” of existing signalling networks. Despite recent advances, this field still lags behind in the artificial reconstruction of cellular processes, and thus demands new modules and switches to create “genetic circuits”. The widely characterised noncanonical nucleic acid secondary structures, G‐quadruplexes are promising candidates to be used as biological modules in synthetic biology. Structural plasticity and functional versatility are significant G‐quadruplex traits for its integration into a biological system and for diverse applications in synthetic circuits.     

Design of Artificial Enzymes: Insights into Protein Scaffolds

The design of artificial enzymes has emerged as a promising tool for the generation of potent biocatalysts able to promote new-to-nature reactions with improved catalytic performances, providing a powerful platform for wide-ranging applications and a better understanding of protein functions and structures. The selection of an appropriate protein scaffold plays a key role in the design process. This review aims to give a general overview of the most common protein scaffolds that can be exploited for the generation of artificial enzymes. Several examples are discussed and categorized according to the strategy used for the design of the artificial biocatalyst, namely the functionalization of natural enzymes, the creation of a new catalytic site in a protein scaffold bearing a wide hydrophobic pocket and de novo protein design. The review is concluded by a comparison of these different methods and by our perspective on the topic.     

Fabrication and properties of 3D printed zirconia scaffold coated with calcium silicate/hydroxyapatite

The scaffold of bone repair needs a variety of material combinations to meet its intended performance; a typical single material such as zirconia has excellent mechanical properties, while hydroxyapatite and calcium silicate are bioactive materials with different degradation rates. In this paper, porous zirconia scaffolds were fabricated using 3D printing technology. The surface of the scaffold was coated by dipping with different contents of calcium silicate and hydroxyapatite to improve the biological activity and mechanical properties. Mechanical tests show that the coating material can effectively fill the pores of the porous scaffold, increasing its compressive strength by an average of 55%. The simulated body fluid (SBF) test showed that the higher calcium silicate in the coating increased the degradation rate. Cell experiments showed that the coated scaffolds exhibited good cytocompatibility and were beneficial to the proliferation and differentiation of cells. In conclusion, coated scaffolds have potential applications in the field of bone repair.     

Laser‐made 3D Auxetic Metamaterial Scaffolds for Tissue Engineering Applications

Exploiting the unique properties of three‐dimensional (3D) auxetic scaffolds in tissue engineering and regenerative medicine applications provides new impetus to these fields. Herein, the results on the fabrication and characterization of 3D auxetic scaffolds for tissue engineering applications are presented. The scaffolds are based on the well‐known re‐entrant hexagonal geometry (bowtie) and they are fabricated by multiphoton lithography using the organic?inorganic photopolymer SZ2080. In situ scanning electron microscopy–microindentations and nanoindention experiments are employed to characterize the photocurable resin SZ2080 and the scaffolds fabricated with it. Despite SZ2080 being a stiff material with a positive Poisson’s ratio, the scaffolds exhibit a negative Poisson’s ratio and high elasticity due to their architecture. Next, mouse fibroblasts are used to seed the scaffolds, showing that they can readily penetrate them and proliferate in them, adapting the scaffold shape to suit the cells’ requirements. Moreover, the scaffold architecture provides the cells with a predilection to specific directions, an imperative parameter for regenerative medicine in many cell‐based applications. This research paves the way for the utility of 3D auxetic metamaterials as the next‐generation adaptable scaffolds for tissue engineering.     

Natural Voltage-Gated Sodium Channel Ligands: Biosynthesis and Biology

Natural product biosynthetic pathways are composed of enzymes that use powerful chemistry to assemble complex molecules. Small molecule neurotoxins are examples of natural products with intricate scaffolds which often have high affinities for their biological targets. The focus of this Minireview is small molecule neurotoxins targeting voltage-gated sodium channels (VGSCs) and the state of knowledge on their associated biosynthetic pathways. There are three small molecule neurotoxin receptor sites on VGSCs associated with three different classes of molecules: guanidinium toxins, alkaloid toxins, and ladder polyethers. Each of these types of toxins have unique structural features which are assembled by biosynthetic enzymes and the extent of information known about these enzymes varies among each class. The biosynthetic enzymes involved in the formation of these toxins have the potential to become useful tools in the efficient synthesis of VGSC probes.     

Chemical Biology: Here to Stay?

The term chemical biology emerged about 25 years ago and encompasses a set of research inquiries at the intersections of chemistry and biology. Before chemical biology there was biological chemistry for 100 years or more, but the traverse from one to the other has not just been a switching of noun and adjective. Over the past quarter century chemists, many from organic synthetic lineages, have become convinced that the open systems of biology have become appropriate venues to bring chemical thinking for library design, screening, and molecular scaffold optimization. Whereas biological chemistry may be described as the universe of chemistry that happens in nature, chemical biologists often bring new, unnatural molecular scaffolds to decipher the logics of biology. That seems a limiting definition and I prefer the mantra: think chemically, act biologically.