结构仿生材料的研究进展

自然界中生物体的优异结构和特性给人类研究材料带来了灵感和启发.借鉴这些生物体的优秀结构特征是结构仿生材料的主要设计思想和方法.重点阐述了仿生增韧陶瓷材料、仿生粘附材料、仿生减阻材料、仿生减振材料和仿生系统应用在设计和制备方面的研究进展,并展望了结构仿生材料的发展前景,强调了多学科协作的重要性.     

仿生材料3D打印

自然界中的生物经过数亿年进化,已经形成了人工材料不可比拟的精妙微结构和优异性能。以生物材料的设计理念作为指导,可以有效推动材料科学和工程领域的发展。虽然自然提供了先进功能材料的设计蓝图,但仍然需要有效的工具和技术来制备实施。3D打印技术具有精密化和快速化的特点,其自下而上的原料累加过程和生物材料的形成过程具有相似性,可制备复杂结构和集成化器件。通过电脑辅助设计,3D打印可以为仿生材料和先进功能材料制造提供平台。综述了3D打印技术在仿生材料领域的应用,指出目前该领域面临的问题,并探讨了3D打印技术和仿生材料相结合的未来发展方向。     

天然和仿生柔性生物结构的设计

自然界中生物材料表现出的力学性能与其结构设计形式紧密相关。柔性生物材料多为多级结构设计,其独特的功能梯度特征使其具备优异的变形能力及良好的断裂韧性。本文借鉴工程结构设计基本单元的思想提出柔性结构仿生元素理念,根据几何形态将结构仿生元素分为：线元素、梁元素、柱元素、板壳元素、薄膜元素及组合元素。根据系统论的观点建立仿生柔性结构设计体系,归纳总结出柔性仿生结构的设计准则,并基于鱼鳞梯度结构设计新型仿生功能梯度板。通过有限元的方法对功能梯度板归一化自然频率进行分析。结果表明,类鱼鳞功能梯度板具有柔韧性及刚度软化特性。阐述了仿生柔性结构的设计方法,包括模仿设计、组合设计及选择匹配设计。     

自组装制备有机/无机层状复合材料

自然界中形成的生物材料在结构和性能上具有优异的配备性。模仿生物矿化的形成机制,利用自组装原理能够仿生合成出性能优良和具有多级结构特点的有机/无机界面层状复合材料。本文在总结近年来最新研究的成果上,简要介绍了自组装和生物矿化的机理,重点阐述了基于无机相层的自组装和以有机大分子为模板自组装制备有机／无机层状复合材料两种合成连径,并对未来的发展趋势做了展望。     

生物材料的离子束表面改性

随着表面处理技术的发展,国内我对如何改善现有的生物材料表面的各种性能,如耐蚀性,耐磨性,生物相容性等进行了研究。各种表面处理的方法受到高度重视,其中离子束表面改性技术,由于其对材料本体无负效应,已被证明是最为成功的一种。本文在综述离子束改性技术在生物材料及器械方面应用的同时,提出将梯度功能材料的新概念与离子束改性技术相结合,用以制备表面性能优异的仿生生物材料。     

生物材料细胞粘附肽仿生修饰的研究进展

RGD(Arg-G1y-Asp)短肽序列是一种细胞粘附肽,能被细胞膜上的整合素识别,参与细胞与基质间的粘附.为改善合成生物材料缺乏细胞识别信号的缺点,可将含RGD序列肽经本体或表面修饰引入材料,使材料具有良好的细胞亲和性.综述了采用含RGD肽对各种合成生物材料进行仿生修饰的研究进展.     

生物功能材料的发展与应用

生物功能材料的发展可分为两个方面，即功能生物材料和仿生功能材料。功能生物材料的研究在于开发生物材料的物理、化学、生物特性的应用。本文着重叙述了生物组织电性能的研究及生物光电材料的应用；提出从生物活性材料活动规律研究入手，由生物模型简化为数学、物理模型从而设计出仿生功能材料的方法。举例说明了生物功能材料的发展对改变传统生产方式及对高科技产业的巨大影响，并对国民经济的发展有很大的促进作用。     

生物材料的仿生构思

过去30年里,生物材料的研究取得了显著成就,但从临床效果看,其与宿主相互作用亟待改善;哪怕是有些应用于长期埋植体内的替代物,常被机体视为异物,从而启迪人们不要仅着眼于从材料的物化性能方面构思生物材料。文章从蛋白质、糖类和脱氧核糖核酸与材料的关系出发,以细胞作为仿生生物材料的蓝本,从分子和细胞水平讨论了生物特异性材料设计,人工细胞外基质的仿生化途径以及通过材料对细胞编程凋亡的调控等方面的研究思路;试图从生命科学的广度和柔性出发,提出在不同层次和水平上进行仿生,从事生物材料设计,解决生物材料与生物体复杂接口问题,使生物材料向智能化和环境友好化发展。     

超疏水表面材料的制备与应用

仿生超疏水表面材料具有特殊微纳米结构,因此表现出自清洁、防污染等一系列优异性能.在荷叶、水黾腿、蝴蝶翅膀等自然界中超疏水性组织和器官的启发下,仿生超疏水表面材料的设计和研发的目标不仅在于模仿生物的功能结构,更主要的是制备组分和结构均可调的超疏水表面,从而获得既有疏水自清洁性,同时强度、耐热、耐酸碱等性能又十分优异的新材料.该类材料在国防、工业、农业、医学和日常生活中均有广阔的应用前景.从超疏水材料纳米界面的结构出发,分析材料的疏水原理及其制备方法,介绍了近几年来该材料的研究进展以及在管道无损运输、房屋建筑和防水等应用领域的探索,展望了其未来的应用方向和前景.     

功能梯度骨质生物材料的研究进展

功能梯度骨质生物材料为根据人体自然骨的特殊结构,结合金属材料和生物陶瓷材料各自的优点而制备的一类既具有仿生孔隙分布,又具有良好力学性能的骨质生物复合材料.简要介绍了功能梯度骨质生物材料的研究背景,评述了Ti基、316L不锈钢基、Co-Cr-Mo基、Ti4Al6V基四大类功能梯度骨质生物材料的研究进展.同时指出,相比其它制备方法,粉末冶金法由于其近净成形的特点在制备功能梯度骨质生物材料时具有更大的优势.     

Bioinspired Materials: from Low to High Dimensional Structure

The surprising properties of biomaterials are the results of billions of years of evolution. Generally, biomaterials are assembled under mild conditions with very limited supply of constituents available for living organism, and their amazing properties largely result from the sophisticated hierarchical structures. Following the biomimetic principles to prepare manmade materials has drawn great research interests in materials science and engineering. In this review, we summarize the recent progress in fabricating bioinspired materials with the emphasis on mimicking the structure from one to three dimensions. Selected examples are described with a focus on the relationship between the structural characters and the corresponding functions. For one‐dimensional materials, spider fibers, polar bear hair, multichannel plant roots and so on have been involved. Natural structure color and color shifting surfaces, and the antifouling, antireflective coatings of biomaterials are chosen as the typical examples of the two‐dimensional biomimicking. The outstanding protection performance, and the stimuli responsive and self‐healing functions of biomaterials based on the sophisticated hierarchical bulk structures are the emphases of the three‐dimensional mimicking. Finally, a summary and outlook are given.     

Assemblies of biomaterials in mesoporous media

Assemblies of biomaterials onto mechanically stable inorganic structure are advantageous for the practical applications because of the potential to improve the stability and performance of biomaterials in the biocatalytic processes. Among many kinds of inorganic materials, mesoporous materials such as mesoporous silica and mesoporous carbon have attracted special attention owing to their well-defined structures and perfectly controlled pore geometries, which would lead to unique functions such as size selective adsorption of biomaterials. In the first part of this review, adsorption behaviors of proteins, enzymes, vitamins, and amino acids in aqueous solutions onto mesoporous media are systematically explained. Pore geometries (pore diameter and volume) of mesoporous materials are the crucial factors for the size selective adsorption of biomaterials, especially proteins, which often have a size comparable to pore dimension. The studies on the adsorption of biomaterials on the mesoporous carbon reveal that hydrophobic interaction between guest molecules and surface of the mesoporous materials is an important parameter which controls the amount of biomaterials adsorption. Enhanced adsorption of biomaterials was commonly observed at their isoelectric point, where electrostatic repulsion is minimized between the biomaterials. In addition, several functions such as biomolecular separation, reactor function, controlled drug release, and photochemical properties are discussed in the latter sections. Studies on assemblies of biomaterials in mesoporous media are still in initial stage, but the development of appropriately designed mesoporous materials would powerfully promote researches in these fascinating unexplored fields.     

仿生有序结构羟基磷灰石研究进展

羟基磷灰石(hydroxyapatite,HAP)与人体硬组织主要无机组分具有相同的化学组成,因而被认为具备良好的生物相容性、可降解性和生物活性,并已在生物医学领域得到广泛应用。迄今为止,形态丰富的HAP纳米材料及其合成方法已经被报道出来,但是具有仿生有序结构的HAP材料及其制备方法仍然是相关领域最具挑战性的方向。在包括牙釉质、皮质骨和松质骨在内的硬组织中,纳米尺度的HAP通常会按照人体受力分布情况呈可控有序结构排列。因此,通过仿生天然硬组织微结构实现HAP的可控有序组装,有望进一步提升传统HAP基生物材料的力学和生物学性能。近年来,包括氧化铝模板法、有机溶剂/小分子调控法、磷酸氢钙相转化法、高分子/蛋白分子诱导矿化法、冷冻铸造等在内的HAP有序结构制备方法已经被发展出来,并实现了在纳米、微米等尺度上有序结构的制备。最近,作者课题组报道了HAP纳米线的扩大化溶剂热制备方法,并进一步提出了适用于控制HAP纳米线有序排列的表面小分子介导的液相自组装策略,获得了尺寸和方向均可控的宏观尺度HAP纳米线仿生有序结构。相比于传统无序结构HAP基生物材料,具有仿生有序结构的HAP表现出了良好的力学和生物学性能,对新型无机生物材料的设计、制备及其生物医学应用研究具有重要的指导意义。综述了仿生有序结构HAP的研究进展,包括其结构组成、合成方法及调控机制,最后总结了仿生有序结构HAP研究领域当前面临的挑战以及未来的发展前景。     

Mechanical adaptation of biological materials — The examples of bone and wood

Many biological materials have the property of being responsive to their environment combined with the ability to adapt to possible changes in this environment. Two prototypical responsive biological materials are presented and confronted with each other: bone and wood. These biomaterials have attracted research interest of materials scientists mainly investigating structure–property relationships. Ageing and diseases of bone and the widespread use of wood as construction material, fuel research from a medical and technological perspective. After describing the structure of bone and wood, the mechanisms of adaptation – adaptive growth and remodelling – are introduced, which allow structural changes in these biomaterials. Four examples are presented how these mechanisms are used for adaptation on different length scales starting from the shape at the macroscopic scale to the composite structure at the nanoscopic scale. In all these examples the biomaterials respond to mechanical stimuli and try to improve their mechanical performance. While some of the embarked strategies are very similar in bone and wood, like the arrangement of fibres and the architecture of the nanocomposite, differences can be observed in other situations like growing a supportive cylindrical structure or in the reorientation of structures. At the core of these differences is the capacity of living bone to deposit material where needed, but also to remove superfluous material. In contrast, a tree can only grow by adding new material.     

Histidine as a key modulator of molecular self-assembly: Peptide-based supramolecular materials inspired by biological systems

Histidine, a versatile proteinogenic amino acid, plays a broad range of roles in all living organisms and behaves as a key mediator of the interactions of biomolecules with inorganic constituents. The self-assembly of histidine-rich peptides and proteins is critical in biology, as the histidine unit is both a multifunctional regulator and an ideal motif for the construction of complex biological structures. In particular, non-covalent interactions between the imidazole ring and other molecular building blocks and metal ions are routinely employed to generate these complexes. Therefore, this strategy can be duplicated in an artificial context to create sophisticated bioactive materials. In this review, we first highlight a clear perspective of the bio-inspired design strategies which can replicate the hierarchical structure of biological systems allowing the engineering of the supramolecular self-assembly of histidine-functionalized peptides. We further summarize advancements in the field of peptide supramolecular structures incorporating histidine residues in the peptide backbone to generate organized functional supramolecular biomaterials with customizable features. We also discuss significant advances and future prospects in supramolecular self-assembly of histidine-functionalized peptides, as well as provide an overview of advanced techniques for the fabrication of histidine-based biomaterials for bio-nanotechnology, optoelectronic engineering, and biomedicine. Overall, artificial supramolecular materials based on histidine functionalized peptides, motivated by the intriguing properties discovered in natural proteins, bear the potential to boost the creation of sustainable bio-inspired materials.     

纳米洋葱状富勒烯的研究现状及前景

通过述评纳米洋葱状富勒烯的结构、制备、生长机理、纯化、修饰及性能,指出:纳米洋葱状富勒烯具有独特的中空笼状及同心壳层结构,是富勒烯家族的一个重要成员,具有许多特殊性能,有望在能源材料、高性能、高温耐磨材料、超导材料和生物医用材料等领域得到广泛的应用.     

A review on nickel-free nitrogen containing austenitic stainless steels for biomedical applications

The field of biomaterials has become a vital area, as these materials can enhance the quality and longevity of human life. Metallic materials are often used as biomaterials to replace structural components of the human body. Stainless steels, cobalt–chromium alloys, commercially pure titanium and its alloys are typical metallic biomaterials that are being used for implant devices. Stainless steels have been widely used as biomaterials because of their very low cost as compared to other metallic materials, good mechanical and corrosion resistant properties and adequate biocompatibility. However, the adverse effects of nickel ions being released into the human body have promoted the development of “nickel-free nitrogen containing austenitic stainless steels” for medical applications. Nitrogen not only replaces nickel for austenitic structure stability but also much improves steel properties. Here we review the harmful effects associated with nickel and emphatically the advantages of nitrogen in stainless steel, as well as the development of nickel-free nitrogen containing stainless steels for medical applications. By combining the benefits of stable austenitic structure, high strength, better corrosion and wear resistance and superior biocompatibility in comparison to the currently used austenitic stainless steel (e.g. 316L), the newly developed nickel-free high nitrogen austenitic stainless steel is a reliable substitute for the conventionally used medical stainless steels.     

Metallotropic liquid crystals formed by surfactant templating of molten metal halides

Liquid crystals consist of anisotropic molecular units, and most are organic molecules. Materials incorporating metals into anisotropic molecules, described as metallomesogens, have been prepared. Anisotropic structures such as one-dimensional chains and two-dimensional layers are frequently observed in solid-state inorganic materials, however, little is understood about structural organization in melts of such materials. Achieving liquid-crystalline behaviour in inorganic fluids should be possible if the anisotropic structure can be retained or designed into the molten phase. We demonstrated the ability to engineer zeolite-type structures into metal halide glasses and liquids. In this work we have engineered lamellar, cubic and hexagonal liquid-crystalline structure in metal-halide melts by controlling the volume fraction and nature of the inorganic block (up to 80 mol%) with respect to alkylammonium surfactants. The high metal content of these liquid-crystalline systems significantly advances the field of metallomesogens, which seeks to combine magnetic, electronic, optical, redox and catalytic properties common to inorganic materials with the fluid properties of liquid crystals.     

Biomimetic Design and Test of Composite Materials

A series of superior properties will make composites the most important structural materials in thenext century.But they are difficult to design owing to the complexity of structure and processing.Biomaterials had been naturally selected and evolved for millions of years,a great variety of their ra-tional composite structures could be taken as our reference in the biomimetic design of compositematerials.There are many difficult problems in the current study on composite materials such as:brittleness of continuous fibers and difficulties in interface design;easy pull-out of short fibers frommatrix causing failure in reinforcing;being less easy in selecting the aspect ratio of whiskers and dif-ficulties in finding the way of toughening composites of ceramic matrices as well as the way of heal-ing inner damages.After describing the distinct composite features,the functional adaptability andself-healing ability of biomaterials,several examples o.f biomimetic design of composite materialshave been listed in this paper:the optimum design of composites simulating bamboo structure;thefine structure of bamboo fibers;the dumb-bell model simulating animal bone;the model on thepull-out of fiber with fractal-tree structure and some tentative works on the healing of inner damagein composite materials The methodology of biomimetic design and its future have been given at theast part of this paper.     

Biomimetic smart interface materials for biological applications

Controlling the surface chemical and physical properties of materials and modulating the interfacial behaviors of biological entities, e.g., cells and biomolecules, are central tasks in the study of biomaterials. In this context, smart polymer interface materials have recently attracted much interest in biorelated applications and have broad prospects due to the excellent controllability of their surface properties by external stimuli. Among such materials, poly(N-isopropylacrylamide) and its copolymer films are especially attractive due to their reversible hydrogen-bonding-mediated reversible phase transition, which mimics natural biological processes. This platform is promising for tuning surface properties or to introduce novel biofunctionalities via copolymerization with various functional units and/or combination with other materials. Important progress in this field in recent years is highlighted.