仿生材料的研究现状

简要地介绍了贝壳珍珠层天然生物材料的结构特征，进而综述了仿生材料的研究现状。     

仿生功能化骨修复材料研究

由肿瘤、炎症及各类创伤而导致的骨组织坏死、病变、缺失及骨折是临床多发病症,自体骨移植虽然是临床治疗的“金标准”,但由于供体受限而很难满足需求。通过对天然骨本身的成分、结构特性及矿化过程的模仿,应用先进材料制备技术,特别是纳米技术,对材料的组成、结构进行设计与凋控,获得仿生型骨修复材料或者对传统材料进行仿生功能化修饰,以满足临床对痫损或缺失的骨组织进行有效修复和功能重建具有重要意义。阐述了仿生功能化骨修复材料的相关研究,主要包括类骨钙磷纳米矿物的合成,有机分子摸板对纳米矿物尺寸和形貌的调控,以及仿生多孔结构支架的构建等。     

仿生结构复合材料研究现状

综述了贝壳珍珠层、蛛丝结构、竹材外密内疏结构、植物的根部网状结构以及骨骼哑铃型结构等天然生物材料的结构特征及其相应的仿生材料近年来的研究进展,展望了结构仿生材料的应用前景.认为应对现有生物体的结构特征与其性能的相关性进行进一步的研究,从材料科学角度研究它们的规律,进行仿生设计,以推动仿生材料学的发展.     

仿生层状复合材料研究概况

从仿生的角度介绍了仿生复合材料尤其是层状复合材料的设计原理，制备方法，主要研究内容和现状。指出了仿生复合材料的应用前景和今后的发展方向。     

仿生防污材料的研究进展

船舶表面的生物污损会带来极大的危害,如何防除生物污损已成为一个世界难题。尽管氧化亚铜等有毒防污剂可以有效防止海生物的附着污损,但这类防污剂对非目标生物也具有负面作用,可能带来严重的生态问题。随着国际社会对有毒防污剂和海洋环境的日益关注,发展环境友好型防污材料已势在必行。人们经常观察到自然界许多生物并没有被其它生物种类寄生聚居,这是因为在自然界中生物自身存在着各不相同但极为有效的防污机制,包括化学性质、物理性质、机械清理、生活习性,以及各种防污机制的组合等,这为研制环境友好型仿生防污材料提供了依据。综述海洋环境中仿生防污材料的研究进展,重点介绍了基于生物防污剂、表面微结构、水凝胶、抗蛋白吸附等特性进行防污的仿生材料研究,并阐述了我国在该领域已经取得的重要技术突破和主要技术成果,展望了仿生防污技术的发展趋势。     

Water‐Rich Biomimetic Composites with Abiotic Self‐Organizing Nanofiber Network

Load‐bearing soft tissues, e.g., cartilage, ligaments, and blood vessels, are made predominantly from water (65–90%) which is essential for nutrient transport to cells. Yet, they display amazing stiffness, toughness, strength, and deformability attributed to the reconfigurable 3D network from stiff collagen nanofibers and flexible proteoglycans. Existing hydrogels and composites partially achieve some of the mechanical properties of natural soft tissues, but at the expense of water content. Concurrently, water‐rich biomedical polymers are elastic but weak. Here, biomimetic composites from aramid nanofibers interlaced with poly(vinyl alcohol), with water contents of as high as 70–92%, are reported. With tensile moduli of ≈9.1 MPa, ultimate tensile strains of ≈325%, compressive strengths of ≈26 MPa, and fracture toughness of as high as ≈9200 J m^?2, their mechanical properties match or exceed those of prototype tissues, e.g., cartilage. Furthermore, with reconfigurable, noncovalent interactions at nanomaterial interfaces, the composite nanofiber network can adapt itself under stress, enabling abiotic soft tissue with multiscale self‐organization for effective load bearing and energy dissipation.     

Bioinspired Catechol‐Terminated Self‐Assembled Monolayers with Enhanced Adhesion Properties

The role of the catechol moiety in the adhesive properties of mussel proteins and related synthetic materials has been extensively studied in the last years but still remains elusive. Here, a simplified model approach is presented based on a self‐assembled monolayer (SAM) of upward‐facing catechols thiol‐bound to epitaxial gold substrates. The orientation of the catechol moieties is confirmed by spectroscopy, which also showed lack of significant amounts of interfering o‐quinones. Local force‐distance curves on the SAM measured by atomic force microscopy (AFM) shows an average adhesion force of 45 nN, stronger than that of a reference polydopamine coating, along with higher reproducibility and less statistical dispersion. This is attributed to the superior chemical and topographical homogeneity of the SAM coating. Catechol‐terminated SAMs are also obtained on high‐roughness gold substrates that show the ability to assemble magnetic nanoparticles, despite their lack of enhanced adhesion at the molecular level. Finally, the influence of the catechol group on the formation and quality of the SAM is explored both theoretically (molecular dynamics simulations) and experimentally using direct‐write AFM lithography.     

Bacterially Produced,Nacre‐Inspired Composite Materials

The impressive mechanical properties of natural composites, such as nacre, arise from their multiscale hierarchical structures, which span from nano‐ to macroscale and lead to effective energy dissipation. While some synthetic bioinspired materials have achieved the toughness of natural nacre, current production methods are complex and typically involve toxic chemicals, extreme temperatures, and/or high pressures. Here, the exclusive use of bacteria to produce nacre‐inspired layered calcium carbonate‐polyglutamate composite materials that reach and exceed the toughness of natural nacre, while additionally exhibiting high extensibility and maintaining high stiffness, is introduced. The extensive diversity of bacterial metabolic abilities and the possibility of genetic engineering allows for the creation of a library of bacterially produced, cost‐effective, and eco‐friendly composite materials.     

SupraCells: Living Mammalian Cells Protected within Functional Modular Nanoparticle‐Based Exoskeletons

Creating a synthetic exoskeleton from abiotic materials to protect delicate mammalian cells and impart them with new functionalities could revolutionize fields like cell‐based sensing and create diverse new cellular phenotypes. Herein, the concept of “SupraCells,” which are living mammalian cells encapsulated and protected within functional modular nanoparticle‐based exoskeletons, is introduced. Exoskeletons are generated within seconds through immediate interparticle and cell/particle complexation that abolishes the macropinocytotic and endocytotic nanoparticle internalization pathways that occur without complexation. SupraCell formation is shown to be generalizable to wide classes of nanoparticles and various types of cells. It induces a spore‐like state, wherein cells do not replicate or spread on surfaces but are endowed with extremophile properties, for example, resistance to osmotic stress, reactive oxygen species, pH, and UV exposure, along with abiotic properties like magnetism, conductivity, and multifluorescence. Upon decomplexation cells return to their normal replicative states. SupraCells represent a new class of living hybrid materials with a broad range of functionalities.     

Mesoporous Silica‐Based Materials with Bactericidal Properties

Bacterial infections are the main cause of chronic infections and even mortality. In fact, due to extensive use of antibiotics and, then, emergence of antibiotic resistance, treatment of such infections by conventional antibiotics has become a major concern worldwide. One of the promising strategies to treat infection diseases is the use of nanomaterials. Among them, mesoporous silica materials (MSMs) have attracted burgeoning attention due to high surface area, tunable pore/particle size, and easy surface functionalization. This review discusses how one can exploit capacities of MSMs to design and fabricate multifunctional/controllable drug delivery systems (DDSs) to combat bacterial infections. At first, the emergency of bacterial and biofilm resistance toward conventional antimicrobials is described and then how nanoparticles exert their toxic effects upon pathogenic cells is discussed. Next, the main aspects of MSMs (e.g., physicochemical properties, multifunctionality, and biosafety) which one should consider in the design of MSM‐based DDSs against bacterial infections are introduced. Finally, a comprehensive analysis of all the papers published dealing with the use of MSMs for delivery of antibacterial chemicals (antimicrobial agents functionalized/adsorbed on mesoporous silica (MS), MS‐loaded with antimicrobial agents, gated MS‐loaded with antimicrobial agents, MS with metal‐based nanoparticles, and MS‐loaded with metal ions) is provided.