Self‐Assembly of Peptide‐Inorganic Hybrid Spheres for Adaptive Encapsulation of Guests
Self‐Assembly of Peptide‐Inorganic Hybrid Spheres for Adaptive Encapsulation of Guests
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DOI：
10.1002/adma.200901889
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发表时间：
2010-03
影响因子：
29.4
通讯作者：
Xuehai Yan;Pengli Zhu;J. Fei;Junbai Li
中科院分区：
文献类型：
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作者：
Xuehai Yan;Pengli Zhu;J. Fei;Junbai Li
Adv本质上是无处不在的。生物启发的纳米结构材料。许多生物活性构建块是从致病过程中得出的。多肽作为分子自组装的核心识别型。他们的合成，易于体现的化学和生物相容性，需要改善这种纳米生物材料的特性和新功能，以使纳米技术的潜在应用基于杂种，超分子系统的构造。构建块和无机组件是实现功能集成的有效策略。过渡金属的阴离子氧化物纳米簇，由于它们在催化，电子，光学，磁性材料，药物和生物学中的潜在应用，因此使用了这种杂种材料的结构的无机成分。酸（PTA）作为多氧化氨基化模型分子，并将其与阳离子二肽（CDP），H-PHE-PHE-NH2 HCl结合起来，该H-PHE-NH2 HCl从FF肽中得出组装预期的杂种。 ，基于生物活性肽和多氧化的共同组合。在自组装过程中，从小分子到纳米级材料的各种各样的自适应封装。在室温下，CDP的1,1,1,3,3,3-HEXAFLUORO-2-丙醇（HFIP）溶液（以1：5的电荷比）。红云悬浮液（在支持信息中的图S1a），表明系统中有一些组装，这些组件与笨重的溶液分开。图2a）表明，组件是胶体球，直径约为100至250 nm。 2a）表明，这种杂化胶体球由PTA和CDP组成，如整个组件中存在钨和碳元素所证明的那样。平均直径为150 nm的球形结构。许多黑暗物体的大小约为1 nm（可归因于单个PTA簇），被肽壳包围，具有较低的电子对比度（图2D）在动态光散射（DLS）测量中，每个POM分子的直径约为1 nm。
Adv. Mater. 2010, 22, 1283–1287 2010 WILEY-VCH Verlag G T IO N Self-assembly, a common process at all scales, is emerging as a powerful, bottom-up approach for the fabrication of novel functional nanoor biomaterials. It is ubiquitous in nature. By learning from nature or imitating the self-assembly process in biological systems, one can delicately design or extract molecular building blocks for the creation of biomimetic or bioinspired nanostructural materials. Many bioactive building blocks for self-assembly are derived with inspiration from a pathogenic process. A known example is that of the diphenylalanine peptide (L-Phe-L-Phe) (FF) which is extracted from Alzheimer’s b-amyloid polypeptide as the core recognitionmotif for molecular self-assembly. Such peptides are a sort of versatile, selfassembling building block in the construction of defined supramolecular structures, owing to their ease of synthesis, facile chemical and biological modification, and biocompatibility. However, improved properties and novel functions for such nanoor biomaterials are needed to arrive at potential applications in nanotechnology. The fabrication of hybrid, supramolecular systems based on the combination of peptide or protein building blocks and inorganic components is an effective strategy to achieve the integration of functions. Herein, polyoxometalates (POMs), a well-known class of anionic oxide nanoclusters of transition metals, are used as possible inorganic components for the fabrication of such hybrid materials, owing to their potential applications in catalysis, electronics, optics, magnetic materials, medicine, and biology. We selected a Keggin-type POM, phosphotungstic acid (PTA) as a polyoxoanion model molecule, and combined it with the cationic dipeptide (CDP), H-Phe-Phe-NH2 HCl, which is derived from the FF peptide to assemble the expected hybrids. Figure 1 shows the suggested process of the formation of such functional hybrid colloidal spheres from the coassembly of PTA and CDP in water. To our knowledge, this is the first time that a stable, spherical structure has been obtained in water, based on the coassembly of a bioactive peptide and a polyoxoanion. The as-prepared colloidal spheres not only display stimuli-responsive properties to pH or temperature, but also lead to a novel function: enabling adaptive encapsulation for a wide variety of guest materials ranging from small molecules to nanoscale materials during self-assembly. The supramolecular assembly in the form of colloidal spheres based on PTA and CDP was initially investigated and prepared by the addition of an aqueous solution of PTA to a 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) solution of CDP (in a 1:5 charge ratio) at room temperature. Such a mixing resulted in an immediate, opalescent, cloudy suspension (Fig. S1a in the Supporting Information), indicating there was some assembly taking place in the system. The precipitates, which were separated from the bulky solution, were imaged using scanning electron microscopy (SEM). An SEM image (Fig. 2a) shows that the assemblies are colloidal spheres with diameters ranging from about 100 to 250 nm. Energy dispersive X-ray (EDX) spectroscopy attached to the SEM (inset in Fig. 2a) indicates that such hybrid colloidal spheres are composed of both PTA and CDP, as evidenced by the presence of tungsten and carbon elements throughout the assemblies. Transmission electron microscopy (TEM) images (Fig. 2b–c) also demonstrate the formation of regular spherical structures with average diameters of 150 nm. The high-resolution TEM (HR-TEM) studies indicate that the hybrid colloidal spheres contain basic structural units consisting of many dark objects approximately 1 nm in size (attributable to single PTA clusters) surrounded by a peptide shell with lower electron contrast (Fig. 2d). The average size of the peptide-encapsulated clusters (PECs) is about 1.4 nm. It is noted that the diameter of each POM molecule with a Keggin structure is around 1 nm. In a dynamic light scattering (DLS) measurement