Biological surface science

Biological surface science (BioSS), as defined here is the broad interdisciplinary area where properties and processes at interfaces between synthetic materials and biological environments are investigated and biofunctional surfaces are fabricated. Six examples are used to introduce and discuss the subject: Medical implants in the human body, biosensors and biochips for diagnostics, tissue engineering, bioelectronics, artificial photosynthesis, and biomimetic materials. They are areas of varying maturity, together constituting a strong driving force for the current rapid development of BioSS. The second driving force is the purely scientific challenges and opportunities to explore the mutual interaction between biological components and surfaces.

Model systems range from the unique water structures at solid surfaces and water shells around proteins and biomembranes, via amino and nucleic acids, proteins, DNA, phospholipid membranes, to cells and living tissue at surfaces. At one end of the spectrum the scientific challenge is to map out the structures, bonding, dynamics and kinetics of biomolecules at surfaces in a similar way as has been done for simple molecules during the past three decades in surface science. At the other end of the complexity spectrum one addresses how biofunctional surfaces participate in and can be designed to constructively participate in the total communication system of cells and tissue.

Biofunctional surfaces call for advanced design and preparation in order to match the sophisticated (bio) recognition ability of biological systems. Specifically this requires combined topographic, chemical and visco-elastic patterns on surfaces to match proteins at the nm scale and cells at the micrometer scale. Essentially all methods of surface science are useful. High-resolution (e.g. scanning probe) microscopies, spatially resolved and high sensitivity, non-invasive optical spectroscopies, self-organizing monolayers, and nano- and microfabrication are important for BioSS. However, there is also a need to adopt or develop new methods for studies of biointerfaces in the native, liquid state.

For the future it is likely that BioSS will have an even broader definition than above and include native interfaces, and that combinations of molecular (cell) biology and BioSS will contribute to the understanding of the “living state”.     

非损伤微测技术及其在生物医学研究中的应用

“非损伤微测技术”或称“无损微测技术”是上世纪末产生的一种用非损伤性的方法获取物体表面特异性离子和分子动态信息的新技术平台。该技术平台是微电子、计算机、精密机械加工、物理、数学、高分子化学、纳米技术及光学显微技术等多学科优秀成果的集成。“非损伤微测技术”可使研究人员在被测样品上获得其他技术难以测到的生理特征和生命活动规律，从而在理论研究和应用领域方面产生实质性的突破。“非损伤微测技术”平台还可以方便地与细胞和分子生物学技术、其他电生理技术和显微荧光成像技术配合使用，从而更全面地揭示各种生命现象及其本质。目前，“非损伤微测技术”平台已被多家科研机构、医院和制药公司所采用，其应用范围涵盖了生物学、生理学、神经生物学、环境科学、药理学、材料科学等诸多领域。文章较详细地介绍了非损伤微测技术及其在生物医学中的应用，其中包括植物、动物研究领域中与生物医学相关问题研究中的应用以及与其他技术结合的应用等。     

The role of surface science in bioengineered materials

Materials employed in biomedical technology are increasingly being designed to have specific, desirable biological interactions with their surroundings, rather than the older common practice of trying to adapt traditional materials to biomedical applications. Moreover, materials scientists are also increasingly deriving new lessons from naturally occurring materials (from mollusk shells to soft animal tissue) about useful composition–structure property relationships that might be mimicked with synthetic materials. Together, these two areas of effort constitute what we may call bioengineered materials. It is possible to set down a reasonably thorough set of characteristics that bioengineered materials have in common. Among these characteristics we discuss the following: self-assembly, bioengineered materials often rely on information content built into structural molecules to determine the order and organization of the material; hierarchical structure, in most bioengineered materials several different length scales of structure are essential and are formed spontaneously and simultaneously via self-assembly; precision synthesis, fundamental to biological material structures is the idea of macromolecules constructed in a precise manner; templating, ordered structures in bioengineered materials are often propagated from one element or set of instructions, to another; specific and non-specific interactions, the forces involved in holding biomaterials structures together. In the future, a carefully selected combination of this set of characteristics will enable us to bioengineer surfaces that are capable to direct and control a desired biological response. Eventually, such bioengineered surfaces will become important tools to comprehend and analyze how materials interact in nature.     

Recognition of biological systems by mass-resolved laser spectroscopy

Molecular clusters are non-covalent aggregates widely recognized as a new state of matter, whose properties are neither those of the individual constituents nor those of their condensed phases. Tailor made molecular clusters have proved to be ideal systems for modelling molecular recognition phenomena and their applications in many scientific fields interlocking the physical and life sciences are now well assessed. In the last few years, it has become possible, through the use of advanced laser techniques, to study the interactions between individual components of a cluster, produced by laser desorption. The studies were carried out developing laser spectroscopic methodologies, capable of characterizing molecular clusters and probing the chemical bond breaking and forming on an extremely short time scale.This paper deals with chiral recognition in gas phase clusters of biological interest through the application of the mass-resolved Resonant Two Photon Ionization (1 and 2 color R2PI) laser technique.The measurement of the spectroscopic shifts and of the fragmentation thresholds of diasteromeric clusters allows the determination of the nature of the interactions which control the formation of biological material and affect their stability and reactivity.     

低温等离子体技术在生物医学上的应用

低温等离子体技术与生物医学似乎是两种风马牛不相及的事物，可是两者的结合却可以对现代科技发展产生重要的影响．许多人都认为21世纪是生物技术的世纪，可见人们对生物技术发展抱着怎样的期待．低温等离子体技术正在成为生物材料和生物医学器件的生产和研究的广阔的平台．文章简要介绍了一些用于材料表面改性的技术以及低温等离子体技术在生物医学方面的应用，并进而讨论了将低温等离子体技术与生物技术相结合的途径以及还需要解决的问题．文章还详细讨论了一种用于表面功能化的脉冲等离子体技术方法作为二者最佳结合的一个典范．文章最后指出，生物医学与等离子体技术的完美结合可能对21世纪的科技发展产生革命性的影响；而为了实现这个目标。需要多学科专家的通力合作．     

表/界面水的扫描探针技术研究进展

表面和界面水在自然界、人们的日常生活以及现代科技中无处不在.它在物理、化学、环境学、材料学、生物学、地质学等诸多基础学科和应用领域起到至关重要的作用.因此,表面和界面水的功能与特性的研究,是水基础科学的一项核心任务.然而,由于水分子之间氢键相互作用的复杂性,及其与水-固界面相互作用的竞争,使得表(界)面水对于局域环境的影响非常敏感,往往需要深入到分子层次研究其微观结构和动力学过程.近年来,新型扫描探针技术的发展使得人们可以在单分子甚至亚分子尺度上对表(界)面水展开细致的实空间研究.本文着重介绍几种代表性的扫描探针技术及其在表(界)面水体系中的应用,包括:超高真空扫描隧道显微术、单分子振动谱技术、电化学扫描隧道显微术和非接触式原子力显微术.此外,本文还将对表(界)面水扫描探针技术研究面临的挑战和未来发展方向进行了展望.     

Surface science studies of environmentally relevant iron (oxy)hydroxides ranging from the nano to the macro-regime

In this prospective, new developments in the study of the structure and reactivity of iron oxyhydroxides are reviewed. These materials are of particular interest, since their surfaces control an extraordinary amount of environmental chemistry. Understanding the environmental interfaces at a molecular level often appears to be a daunting scientific endeavor at first glance. Surfaces of interest range from the nano to micron regime and appear in the environment in varying shapes and sizes. Often the powerful suite of vacuum-based surface science tools are not applicable, since the surfaces of environmental particles can vary from amorphous to semi-crystalline and their surface reactivity is often affected by varying levels of surface hydration. However, the introduction of new and powerful surface probes and advancements in computational chemistry are allowing surface scientists to shed light on these hidden interfaces and how they control environmental chemistry.     

交叉传播构型的和频振动光谱

报道和频振动光谱在交叉传播的实验构型下的理论公式推导和实验结果. 在交叉传播的和频振动光谱实验室中,可见光和红外光通过相互垂直的入射面同时照射在界面上,从而避免了对使用同时能够透过可见和红外激光束的光学元件的要求. 这种交叉实验构型能够直接应用到封闭在真空或者压力腔体中的界面,使得在用远红外直接探测金属氧化物及其它低频界面振动模式实验的窗口材料有更多的选择. 这一交叉实验构型的潜在应用包括表面科学、材料科学、基础催化科学以及低温下的分子科学等方面.     

Real time chemical dynamics at surfaces

It is a major goal in surface science to make movies of molecules on surfaces, in which the reaction of the molecules on the surface can be followed on a femtosecond time scale, with sub-nanometer resolution. By moving the actors (the molecules) to precisely determined positions on the stage (the surface) at some well-defined moment in time, and subsequently making a space- and time-resolved documentary of what happens next, we would be able to understand the reactive interactions between molecules on surfaces in the greatest possible detail. This would enable us to set the stage and bring together the actors in such a way as to produce the chemical outcomes our society needs, by improving existing catalysts and designing novel catalysts, and by engineering novel reactions on surfaces. Any future director of such movies needs to know which techniques (i.e., which theoretical and experimental methods) hold promise for movie making, what has been done with these techniques, and what can be done with appropriate extensions. The methods we discuss are: (i) the time-dependent wave packet method, which is a theoretical method for simulating molecule–surface reactions with sub-nanometer resolution on a femtosecond time scale, (ii) molecular beam experiments, which allow detailed investigation of the molecule–surface interaction at a molecular level, and (iii) time-resolved laser pump–probe experiments, which allow reactions to be studied with femtosecond resolution. In particular, we discuss (i) theoretical studies of the dissociation reaction of hydrogen on metal surfaces, the reactive system presently understood at the greatest level of detail, (ii) the reactive and non-reactive scattering of heavy diatomics (NO,CO) from metal surfaces, and (iii) the competition between reaction of coadsorbed CO with O and desorption of CO, again on a metal surface. We examine possibilities to extend these methods to make movies at the desired level of detail. We also discuss which reactions are likely to provide good material for plots of movies that will be exciting for future generations of surface scientists.     

Biological functionality of active enzyme structures immobilized on various solid surfaces

We have investigated biological functionality of immobilized enzyme structures according to the immobilizing routes and the surface properties. Horse radish peroxidase (HRP) was immobilized on various solid surfaces such as gold, SiO₂, sapphire and anodized aluminum oxide (AAO) membrane via non-specific adsorption, avidin-mediated and biotin/avidin-mediated layer-by-layer (LBL) assembly. The catalytic activity as a measure of biological functionality, of the biotin-HRP immobilized by avidin-mediated LBL assembly was found to be better than that of the directly adsorbed HRP on the surfaces of gold, SiO₂, sapphire and AAO due to the easy accessibility of reactants to active sites as well as the retention of three dimensional native structure of enzyme for bioactive functionality. In addition, the catalytic activity of the biotin-HRP in LBL-assembled avidin/biotin-HRP on AAO membrane was found to be highly better than that on other substrates due to the increasing amount of immobilized HRP which can be attributed to the high surface area of the substrate. SEM images show that the functional avidin/biotin-HRP enzyme structures were successfully realized by a sequential process of non-specific adsorption and LBL assembly via biotin–avidin interaction.