Chiral Ceramic Nanoparticles and Peptide Catalysis
Chiral Ceramic Nanoparticles and Peptide Catalysis
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DOI：
10.1021/jacs.7b01445
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发表时间：
2017-10-04
影响因子：
15
通讯作者：
Kotov, Nicholas A.
中科院分区：
文献类型：
--
作者：
Jiang, Shuang;Chekini, Mahshid;Kotov, Nicholas A.
纳米粒子及其组装体的手性研究主要针对贵金属和II-VI半导体。然而，陶瓷纳米颗粒在自然界中代表了大多数纳米材料。陶瓷的坚固性和其他固有特性为催化、生物医学科学和光学提供了技术机会。本文报道了以分散在乙醇中的WO_3-x中心点H_2O为代表的手性陶瓷纳米颗粒的制备。金属氧化物核心的手性平均尺寸约为1.6 nm，由Pro和Asp配体通过生物向纳米手性转移而赋予手性。氨基酸通过解离的羧基形成的C-O-W键和弱配位的氨基连接到NP表面。令人惊讶的是，Pro和Asp包覆的NPs的主要圆二色谱带不同，尽管NPs的几何形状相似；Pro和Asp修饰的NPs的主要圆二色谱带分别位于400-700 nm和500-1100 nm。两类NPs主手性带光谱位置的差异与两种氨基酸与NP表面的分子结合有关；Asp与Pro相比增加了一个C-O-W键，导致无机晶格更强的扭曲和与无机核的手性相关的更强的Cd带强度。原子分子动力学模拟证实了WO_3-x中心点H_2O原子结构的手性。氨基酸与矿物表面的亲和性与WO_3-x中心点H_2O纳米粒子的催化能力有关。我们发现，NPs促进了多肽键的形成，导致了Asp-Asp和Asp-Pro二肽的形成。氧化钨的手性、化学反应性和生物兼容性创造了与手性光学、化学技术和生物医学相关的独特性能组合。
The chirality of nanoparticles (NPs) and their assemblies has been investigated predominantly for noble metals and II VI semiconductors. However, ceramic NPs represent the majority of nanoscale materials in nature. The robustness and other innate properties of ceramics offer technological opportunities in catalysis, biomedical sciences, and optics. Here we report the preparation of chiral ceramic NPs, as represented by tungsten oxide hydrate, WO3-x center dot H2O, dispersed in ethanol. The chirality of the metal oxide core, with an average size of ca. 1.6 nm, is imparted by proline (Pro) and aspartic acid (Asp) ligands via bio-to-nano chirality transfer. The amino acids are attached to the NP surface through C-O-W linkages formed from dissociated carboxyl groups and through amino groups weakly coordinated to the NP surface. Surprisingly, the dominant circular dichroism bands for NPs coated by Pro and Asp are different despite the similarity in the geometry of the NPs; they are positioned at 400-700 nm and 500-1100 nm for Pro- and Asp-modified NPs, respectively. The differences in the spectral positions of the main chiroptical band for the two types of NPs are associated with the molecular binding of the two amino acids to the NP surface; Asp has one additional C-O-W linkage compared to Pro, resulting in stronger distortion of the inorganic crystal lattice and greater intensity of CD bands associated with the chirality of the inorganic core. The chirality of WO3-x center dot H2O atomic structure is confirmed by atomistic molecular dynamics simulations. The proximity of the amino acids to the mineral surface is associated with the catalytic abilities of WO3-x center dot H2O NPs. We found that NPs facilitate formation of peptide bonds, leading to Asp-Asp and Asp-Pro dipeptides. The chiroptical-activity, chemical reactivity, and biocompatibility of tungsten oxide create a unique combination of properties relevant to chiral optics, chemical technologies, and biomedicine.