肽自组装纳米材料的研究进展

近年来,多肽分子自组装作为合成一系列新型纳米材料的有效途径受到了广泛关注和研究.通过分子自组装,多肽分子可结合成具有不同功能的蛋白质分子,从而可进一步设计成具有特殊结构和功能的纳米材料,在仿生医学、组织工程、药物缓释及生物材料表面工程等方面有着巨大的应用潜力.本文主要综述了肽自组装纳米材料的研究现状与制备方法.     

超声后RADA16-I短肽纳米纤维支架重组装及成胶的研究

RADA16-I自组装短肽水溶液中形成纳米纤维并在盐离子作用下触发成水凝胶.RADA16-I纤维被大功率超声打断为小的原纤维片段.用AFM、CD和流变仪研究超声后纤维的重组装及其成胶性质.实验发现,超声未破坏纳米纤维二级结构,纤维仍保持β-sheet构型,超声4h后,小片段重组装为500nm的纤维,纤维虽未恢复到原长度,但仍未丧失其触发成胶的能力,只是在相同触发时间内达不到超声前的储能模量G′.还研究了超声对纳米纤维和成胶性能的影响,并提出相应的分子模型,这有助于短肽生物材料的应用,并对淀粉样蛋白病变的机理有一定的启示作用.     

中国研究亮点：新纳米生物材料

来自四川大学华西医院纳米生物医学技术与膜生物学研究所的研究人员首次设计一种“智能化”的半程电荷匹配短肽，通过调节浓度和施加超声等外部作用，能人为地控制短肽形成“渔网式”或“席状”的纳米生物材料。这一研究成果公布在《美国国家科学院院刊}（PNAS）杂志上。以往自组装纳米生物材料的形成多是自发形成，很难人为控制纳米材料的形成过程和材料特性。     

小分子硼酸肽的自组装

利用FMOC化学固相多肽合成法合成了3种含精氨酸的小分子硼酸肽(标记为BPs(1-3))。在生理pH下,含阳离子的硼酸肽可自组装形成有序超分子纳米组装体。二羟基酚染料茜素红与硼酸肽可特异性结合形成五元环硼酸酯,伴随荧光和颜色的显著变化,可进一步调控硼酸肽的自组装行为。通过扫描电镜研究茜素红调控前后硼酸肽的自组装形态,并用红外光谱和圆二色谱研究其自组装机理。结果表明,3种含精氨酸硼酸肽在生理pH下可自组装形成不同的超分子纳米组装体。通过茜素红的调控,茜素红/硼酸肽化合物,可自组装形成更有序,更精致的超分子聚集体。     

铁离子掺杂TiO2 的制备及其光催化性能

将Bola型两亲性短肽KI₃E在水溶液中组装成稳定的纤维状结构,以其自组装体作为有机模板并使用氨丙基三乙氧基硅烷为结构导向剂,利用其对TiO₂前驱体-二(2-羟基丙酸)二氢氧化二铵合钛的水解催化作用以及肽模板与铁离子之间的分子识别作用在TiO₂矿化沉积的同时引入铁离子,在温和的水溶液中制备出铁离子掺杂TiO₂纳米材料。使用TEM、BET、UV-vis DRS、XPS、XRD等手段对其结构和性能进行了表征。结果表明,铁元素以Fe²⁺/Fe³⁺的形式存在于TiO₂晶格中,抑制了晶体生长并使晶粒尺寸变小。同时,铁离子的掺杂减小了TiO₂的禁带宽度,提高了对可见光的响应和催化性质。铁离子掺杂量为0.5% TiO₂,其光催化性能最好。     

DNA纳米材料的应用研究进展

DNA作为生物遗传信息的储存分子,因其具有纳米尺寸、分子识别和可操控性等特点还可以作为一种优良的纳米材料。本文介绍了DNA的材料学性质,DNA作为纳米材料近年来在纳米自组装、分子检测和药物输送载体上的应用研究进展,并展望了DNA纳米材料未来的应用前景和发展方向。     

纳米与粉体材料

美让拟肽自我组装成纳米绳子据报道,美国科学家在最新一期的《美国化学学会会刊》上表示,他们诱导聚合物自我编织成了束状的纳米绳子,该纳米绳基本达到了生物材料所具有的复杂性和功能,且非常坚固,足以应付受热和干燥等恶劣环境,这是科学家在研制具备天然材料复杂性和功能的自组装纳米材料道路上所取得的最新进展。     

纳米与粉体材料

美让拟肽自我组装成纳米绳子据报道,美国科学家在最新一期的《美国化学学会会刊》上表示,他们"诱导"聚合物自我编织成了束状的纳米绳子,该纳米绳基本达到了生物材料所具有的复杂性和功能,且非常坚固,足以应付受热和干燥等恶劣环境,这是科学家在研制具备天然材料复杂性和功能的自组装纳米材料道路上所取得的最新进展。     

自组装制备纳米材料的研究现状

综述了纳米材料的各种制备方法，提出了应用自组装技术制备纳米材料。评述了其在制备纳米材料时的机理、优缺点，并对国内外应用自组装技术制备纳米材料(如纳米团簇、纳米管、纳朱膜等)的研究现状进行了综述。     

RADA16-I纳米短肽水凝胶力学强度的调控

研究了RADA16-I纳米短肽的二级结构和微观形态及其在不同溶液触发下形成的水凝胶的力学强度.试验结果表明,该短肽在水溶液中形成典型的β-sheet结构,这对其形成纳米纤维十分重要.此外,研究发现采用不同的溶液触发得到的水凝胶的力学强度可在一定范围内变化,符合DLVO理论.这可为组织工程提供强度可调控的纳米纤维支架材料.     

Constructing biomaterials using self-assembling peptide building blocks

Molecular self-assembly is ubiquitous in nature and has recently emerged as a new bottom-up approach in constructing biomaterials. Synthetic peptides assemble through specific molecular recognition and form diverse nanostructures. The resulting versatile peptide self-assemblies may be used in a wide range of biological and medical applications. Examples of two self-assembling peptide systems are presented and techniques for self-assembly control are discussed.     

Dynamic behaviors of lipid-like self-assembling peptide A6D and A6K nanotubes

Nanoscience and nanotechnology require development of nanomaterials that are amiable for molecular design from bottom up. Molecular designer self-assembling peptides are one of such nanomaterials that will become increasingly important for the endeavor. Peptides have not only been used in all aspects of biomedical and pharmaceutical research and medical products, but also have had enormous impact in nascent field of designed biological materials. We here report the dynamic structures of lipid-like designer peptide A6D (AAAAAAD) and A6K (AAAAAAK) that undergo self-assembly into nanotubes in water and salt solution. We not only analyzed their self-assemblies using dynamic light scattering to determine the critical aggregation concentration (CAC), but also use atomic force microscope to observe their nanostructures. We also propose a simple scheme by which these lipid-like peptides self-assemble into dynamic nanostructures. Since the knowledge of CAC is important for uses of these peptides for a variety of applications, these findings may have significant implications in the study of molecular self-assembly and for a wide range of utilities of designer self-assembling peptide materials.     

多肽自组装及其在生物医学中的应用

多肽自组装广泛存在于自然界中。自组装多肽分子成分简单,生物相容性良好,自组装过程受多方面因素的影响,在生物医学材料方面具有巨大的应用前景。介绍了多肽分子自组装技术的概念和多肽自组装过程中的影响因素(氨基酸的组成和序列、温度、pH值、离子强度、多肽浓度、超声波),综述了多肽自组装系统的种类和多肽自组装技术在创伤修复、药物释放载体以及组织工程支架方面的应用。     

Beta‐Sheet‐Forming,Self‐Assembled Peptide Nanomaterials towards Optical,Energy, and Healthcare Applications

Peptide self‐assembly is an attractive route for the synthesis of intricate organic nanostructures that possess remarkable structural variety and biocompatibility. Recent studies on peptide‐based, self‐assembled materials have expanded beyond the construction of high‐order architectures; they are now reporting new functional materials that have application in the emerging fields such as artificial photosynthesis and rechargeable batteries. Nevertheless, there have been few reviews particularly concentrating on such versatile, emerging applications. Herein, recent advances in the synthesis of self‐assembled peptide nanomaterials (e.g., cross β‐sheet‐based amyloid nanostructures, peptide amphiphiles) are selectively reviewed and their new applications in diverse, interdisciplinary fields are described, ranging from optics and energy storage/conversion to healthcare. The applications of peptide‐based self‐assembled materials in unconventional fields are also highlighted, such as photoluminescent peptide nanostructures, artificial photosynthetic peptide nanomaterials, and lithium‐ion battery components. The relation of such functional materials to the rapidly progressing biomedical applications of peptide self‐assembly, which include biosensors/chips and regenerative medicine, are discussed. The combination of strategies shown in these applications would further promote the discovery of novel, functional, small materials.     

Preparation and characterization of ZnS nanoparticles synthesized from chitosan laurate micellar solution

Synthesis of ZnS nanostructured materials has been performed in the micellar solution system, containing chitosan laurate as the surfactant. The self-assembling of the surfactant molecules in water solution can form unique architecture that can be adopted as the reaction template for the formation of nanomaterials. The synthesized nanomaterials have been characterized by energy filter transmission electron microscopy (EFTEM), Energy Dispersive X-ray Analysis (EDAX), X-ray diffractometry (XRD) and UV–Visible absorption measurement in order to determine the size, morphology, composition, crystal structure and optical behavior of the products. The spectroscopic results showed that the synthesized nanoparticles exhibited strong quantum confinement effect as the optical band gap increased significantly as compared to the bulk materials. In addition, the size of the resulting nanoparticles is greatly affected by the surfactant concentration and range from 2 to 10 nm. It was found that the nanomaterials obtained existed in face-centered cubic structure and exhibited the characteristic line broadening feature in the XRD patterns.     

自组装多肽支架材料的研究进展

多肽分子可以利用氢键、疏水性作用、π-π堆积作用等非共价键力自组装形成形态与结构特异的多肽分子聚集体,如分子积木、分子开关、分子涂料及纳米纤维等,由于多肽分子良好的生物相容性和可调控的降解性,自组装多肽在组织工程、药物缓释等方面表现出巨大的应用潜力。本文总体介绍了多肽自组装的几种结构模型及自组装的设计原则,重点叙述了自组装多肽作为组织工程支架材料的研究进展。     

Systematic studies of a self-assembling peptide nanofiber scaffold with other scaffolds

A designer self-assembling peptide nanofiber scaffold has been systematically studied with 10 commonly used scaffolds in a several week study using neural stem cells (NSC), a potential therapeutic source for cellular transplantations in nervous system injuries. These cells not only provide a good in vitro model for the development and regeneration of the nervous system, but may also be helpful in testing for cytotoxicity, cellular adhesion, and differentiation properties of biological and synthetic scaffolds used in medical practices. We tested the self-assembling peptide nanofiber scaffold with the most commonly used scaffolds for tissue engineering and regenerative medicine including PLLA, PLGA, PCLA, collagen I, collagen IV, and Matrigel. Additionally, each scaffold was coated with laminin in order to evaluate the utility of this surface treatment. Each scaffold was evaluated by measuring cell viability, differentiation and maturation of the differentiated stem cell progeny (i.e. progenitor cells, astrocytes, oligodendrocytes, and neurons) over 4 weeks. The optimal scaffold should show high numbers of living and differentiated cells. In addition, it was demonstrated that the laminin surface treatment is capable of improving the overall scaffold performance. The designer self-assembling peptide RADA16 nanofiber scaffold represents a new class of biologically inspired material. The well-defined molecular structure with considerable potential for further functionalization and slow drug delivery makes the designer peptide scaffolds a very attractive class of biological material for a number of applications. The peptide nanofiber scaffold is comparable with the clinically approved synthetic scaffolds. The peptide scaffolds are not only pure, but also have the potential to be further designed at the molecular level, thus they promise to be useful for cell adhesion and differentiation studies as well as for future biomedical and clinical studies.     

Constructing biomaterials using self-assembling peptide building blocks

Molecular self-assembly is ubiquitous in nature and has recently emerged as a new bottom-up approach in constructing biomaterials. Synthetic peptides assemble through specific molecular recognition and form diverse nanostructures. The resulting versatile peptide self-assemblies may be used in a wide range of biological and medical applications. Examples of two self-assembling peptide systems are presented and techniques for self-assembly control are discussed.     

Self-assembling peptide nanofiber hydrogels for central nervous system regeneration

Central nervous system (CNS) presents a complex regeneration problem due to the inability of central neurons to regenerate correct axonal and dendritic connections. However, recent advances in developmental neurobiology, cell signaling, cell--matrix interaction, and biomaterials technologies have forced a reconsideration of CNS regeneration potentials from the viewpoint of tissue engineering and regenerative medicine. The applications of a novel tissue regeneration-inducing biomaterial and stem cells are thought to be critical for the mission. The use of peptide nanofiber hydrogels in cell therapy and tissue engineering offers promising perspectives for CNS regeneration. Self-assembling peptide undergo a rapid transformation from liquid to gel upon addition of counterions or pH adjustment, directly integrating with the host tissue. The peptide nanofiber hydrogels have mechanical properties that closely match the native central nervous extracellular matrix, which could enhance axonal growth. Such materials can provide an optimal three dimensional microenvironment for encapsulated cells. These materials can also be tailored with bioactive motifs to modulate the wound environment and enhance regeneration. This review intends to detail the recent status of self-assembling peptide nanofiber hydrogels for CNS regeneration.     

Bio-inspired supramolecular self-assembly towards soft nanomaterials

Supramolecular self-assembly has proven to be a reliable approach towards versatile nanomaterials based on multiple weak intermolecular forces. In this review, the development of bio-inspired supramolecular self-assembly into soft materials and their applications are summarized. Molecular systems used in bio-inspired “bottom-up self-assembly” involve small organic molecules, peptides or proteins, nucleic acids, and viruses. Self-assembled soft nanomaterials have been exploited in various applications such as inorganic nanomaterial synthesis, drug or gene delivery, tissue engineering, and so on.