Biomimetic interfaces based on S-layer proteins,lipid membranes and functional biomolecules

Designing and utilization of biomimetic membrane systems generated by bottom-up processes is a rapidly growing scientific and engineering field. Elucidation of the supramolecular construction principle of archaeal cell envelopes composed of S-layer stabilized lipid membranes led to new strategies for generating highly stable functional lipid membranes at meso- and macroscopic scale. In this review, we provide a state-of-the-art survey of how S-layer proteins, lipids and polymers may be used as basic building blocks for the assembly of S-layer-supported lipid membranes. These biomimetic membrane systems are distinguished by a nanopatterned fluidity, enhanced stability and longevity and, thus, provide a dedicated reconstitution matrix for membrane-active peptides and transmembrane proteins. Exciting areas in the (lab-on-a-) biochip technology are combining composite S-layer membrane systems involving specific membrane functions with the silicon world. Thus, it might become possible to create artificial noses or tongues, where many receptor proteins have to be exposed and read out simultaneously. Moreover, S-layer-coated liposomes and emulsomes copying virus envelopes constitute promising nanoformulations for the production of novel targeting, delivery, encapsulation and imaging systems.     

纳米陶瓷与纳米陶瓷粉末

八十年代中期发展起来的纳米陶瓷,使材料的超塑性、强度大为提高,对材料的电学、热学、磁学、光学性质产生重要影响,为材料的利用开拓了一个崭新的领域,已成为材料科学研究的热点之一．本文对纳米陶瓷的烧结与性能、纳米陶瓷粉体的制备及性能表征作了简要的综述．     

导电聚合物修饰的柔性神经微电极的制备与界面性质

本研究提供了一种简易、低成本的工艺和方法,进行神经微电极的性能改进,来改善神经电极/神经组织的界面特性。首先采用光敏型聚酰亚胺(Durimide 7510)作为微电极基质材料制备了一种柔性神经微电极;然后电化学合成导电聚合物聚噻吩PEDOT/LiClO4,进行神经微电极位点的表面修饰;最后测试和评价了神经微电极的表面形貌、电学性能及其生物相容性。结果表明导电聚合物粗糙的菜花状表面形貌提供了更大的界面表面积,因此电极阻抗降低到原来的1/20,微电极的电荷注入能力也增加了约100倍。细胞生物学实验也表明,导电聚合物修饰的柔性微电极上,细胞生长状态良好,与未修饰的柔性微电极下相比,粘附率与存活率均有明显改善,粘附率较修饰前增加了92.5%,存活率也由69.2%提高到85.4%。     

Nano Research

AlMS ＆ SCOPE Nano Research is a peer-reviewed, international and interdisciplinary journal that focuses on all aspects of nanoscience and nanotechnology. Submissions are solicited in all topical areas, ranging from basic aspects of the science of nanoscale materials to practical applications of such materials.     

纳米粉体超细纳米研磨技术交流

纳米科技是21世纪科技发展的重要技术领域,纳米科技将创造另一波技术创新及产业革命。其应用领域非常广,遍及电子、光电、医药生化、化纤、建材、金属及各基础产业。不论其应用领域为何,所需要用的材料均为次微米或纳米级尺度材料。如何得到纳米级粉体及将纳米级材料分散到其最终产品已成为目前产业、经济及学术界共同的研究课题。文章针对如何得到纳米粉体研磨及将纳米材料分散到其最终产品等技术进行探讨。     

纳米粉体之派勒超细纳米研磨技术交流

纳米科技是本世纪科技发展的重要技术领域,纳米科技将创造另一波技术创新及产业革命。其应用领域非常广,遍及电子产业、光电产业、医药生化产业、化纤产业、建材产业、金属产业、基础产业、…等。不论其应用领域为何,所需要用的材料均为次微米或纳米级尺度之材料。如何得到纳米级粉体及如何将纳米级材料分散到其最终产品已成为目前产、经及学术界共同之研究课题。本文将针对如何得到纳米粉体研磨及如何将纳米材料分散到其最终产品技术加以详加探讨。     

Electrifying interfaces

Electrochemical processes at electrified or polarized phase boundaries and methods for charging phase boundaries are discussed. An important type of interface, the three-phase junction, is introduced and processes at three-phase junctions are compared with those occurring at two-phase junctions. Finally, pairing charged interfaces is considered as a methodology for a more efficient use of electrical energy in microscale electrochemical processes. Chemical processes triggered by currents in the ultimate type of paired electrode system, a tunnel junction, are discussed.     

纳米磁性液体

综合论述了近20年来纳米磁性液体在国内外的发展历史及概况,首先重点介绍了目前纳米磁性液体按照不同分类标准的分类、纳米磁性液体的不同制备方法、纳米磁性液体的基本特征与工作机理,最后详细介绍了纳米磁性液体依据其独有的特殊性能联系于实际中的典型应用.     

Engineering functional protein interfaces for immunologically modified field effect transistor (ImmunoFET) by molecular genetic means

The attachment and interactions of analyte receptor biomolecules at solid-liquid interfaces are critical to development of hybrid biological-synthetic sensor devices across all size regimes. We use protein engineering approaches to engineer the sensing interface of biochemically modified field effect transistor sensors (BioFET). To date, we have deposited analyte receptor proteins on FET sensing channels by direct adsorption, used self-assembled monolayers to tether receptor proteins to planar FET SiO2 sensing gates and demonstrated interface biochemical function and electrical function of the corresponding sensors. We have also used phage display to identify short peptides that recognize thermally grown SiO2. Our interest in these peptides is as affinity domains that can be inserted as translational fusions into receptor proteins (antibody fragments or other molecules) to drive oriented interaction with FET sensing surfaces. We have also identified single-chain fragment variables (scFvs, antibody fragments) that recognize an analyte of interest as potential sensor receptors. In addition, we have developed a protein engineering technology (scanning circular permutagenesis) that allows us to alter protein topography to manipulate the position of functional domains of the protein relative to the BioFET sensing surface.     

Three-layer phosphorene-metal interfaces

Phosphorene has attracted much attention recently as an alternative channel material in nanoscale electronic and optoelectronic devices due to its high carrier mobility and tunable direct bandgap. Compared with monolayer (ML) phosphorene, few-layer (FL) phosphorene is easier to prepare, is more stable in experiments, and is expected to form a smaller Schottky barrier height (SBH) at the phosphorene-metal interface. Using ab initio electronic structure calculations and quantum transport simulations, we perform a systematic study of the interfacial properties of three-layer (3L) phosphorene field effect transistors (FETs) contacted with several common metals (Al, Ag, Au, Cu, Ti, Cr, Ni, and Pd) for the first time. The SBHs obtained in the vertical direction from projecting the band structures of the 3L phosphorene-metal systems to the left bilayer (2L) phosphorenes are comparable with those obtained in the lateral direction from the quantum transport simulations for 2L phosphorene FETs. The quantum transport simulations for the 3L phosphorene FETs show that 3L phosphorene forms n-type Schottky contacts with electron SBHs of 0.16 and 0.28 eV in the lateral direction, when Ag and Cu are used as electrodes, respectively, and p-type Schottky contacts with hole SBHs of 0.05, 0.11, 0.20, 0.30, 0.30, and 0.31 eV in the lateral direction when Cr, Pd, Ni, Ti, Al, and Au are used as electrodes, respectively. The calculated polarity and SBHs of the 3L phosphorene FETs are generally in agreement with the available experiments.

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Cell biology at interfaces

A brief review is presented of the significant developments in the understanding of the processes involved in cell adhesion both to other cells and to substrates. The relationship between general cellular behaviour and cell adhesion is a result of the importance of the cytoplasmic cytoskeleton to most cellular processes. Interaction between a substrate and the cell is mediated through intramembranous proteins, such as the integrins. The intramembranous proteins, in turn, influence the assembly of the microfilamentous structures in the cytoplasm. Changes in the state of the microfilaments are accompanied by modifications in the behaviour of both microtubules and intermediate filaments. The expression of different types of cytoskeletal configuration result from differing types of cell-cell or cell-substratum encounters. This leads to significant changes in resultant cellular behaviour. It is argued that an understanding of changes that result from cell-biomaterial interactions, at the ultrastructural level, is necessary in order to assess the biocompatability of implant materials.     

Feeble interfaces in bimaterials

Summary In the present paper, the thermal and thermo-elastic response of a bi-material to temperature changes is analyzed, when its interface exhibits a simultaneous weakness in traction transferring and heat flow conducting (feeble interface). Such a pathological behavior of an interface is described by two sets of constitutive relationships relating the heat flow passing through the interface to the temperature jump and the interfacial components of the traction to those of the displacement jump. The bimaterial model considered is that of a circular inhomogeneity in an elastic matrix with linear forms of the constitutive relationships. When the solutions of both heat conduction and thermoelastic problems with a perfect interface are known, the corresponding problems with a feeble interface are reduced to the solution of two dislocation problems: a heat conduction problem with an appropriate temperature dislocation applied across the interface, and an elasticity problem with an appropriate displacement dislocation of Somigliana type acting across the interface. For both dislocation problems, general representations of their solutions in terms of two-phase potential functions of complex variables are provided. Detailed analytical results are given for a circular inhomogeneity with a feeble interface disturbing a linear distribution of the temperature change in the matrix. In this case, the stress field within the inhomogeneity has a linear distribution and it vanishes for the limiting case of a sliding interface. For a specific value of the interface parameter H, which characterizes the thermal imperfection, there are no shear stresses within the inhomogeneity. Finally, since the constitutive laws describing the thermal and mechanical interface behavior correlate tensors of different order, the resulting fields in the system are drastically affected by the inhomogeneity size.     

纳米有机光电功能材料

本文简要综述了有机纳米光电功能材料的研究进展。详细讨论了有机纳米薄膜的制备方法、结构表征、性能研究及应用前景。     

纳米氧化铜粉的合成

以Cu(NO3)2为原料,NaOH为沉淀剂,蒸馏水为溶剂,采用化学沉淀法结合超声场作用制备出了纳米氧化铜颗粒.经XRD、TEM、差热扫描分析(DSC)以及粒度分析仪检测,所获得颗粒平均粒度达到55nm.此方法制备的氧化铜颗粒形状规则、粒度分布范围窄、纯度高.同时探讨了超声场作用下的机理以及对制备工艺过程和最终产物的影响.讨论了溶液的pH值、反应物的浓度、表面活性剂、反应温度和反应时间对颗粒尺寸的影响.在探讨如何保持纳米颗粒的分散性方面,采用了多种表面活性剂进行试验,发现聚乙二醇(6000)对纳米氧化铜颗粒的保存有着显著的效果,静置20天几乎看不到任何沉降现象.