Self-assembly and accurate preparation of Au nanoparticles in the aqueous solution of a peptide A6D and a zwitterionic C14DMAO
Self-assembly and accurate preparation of Au nanoparticles in the aqueous solution of a peptide A6D and a zwitterionic C14DMAO
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DOI：
10.1039/c3sm50444a
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发表时间：
2013-01-01
期刊：
影响因子：
3.4
通讯作者：
Hao, Jingcheng
中科院分区：
文献类型：
--
作者：
Dou, Yingying;Xu, Hai;Hao, Jingcheng
由于多肽分子之间的静电相互作用、氢键、疏水相互作用和/或其他弱相互作用，在水中获得了表面活性剂样肽的自组装结构，如纳米管、纳米带、纳米纤维和纳米囊泡。本文首先在室温下将肽Ac-AAAAAAD-NH2 （a (6)D）与两性离子表面活性剂十四烷基二甲氨基氧化物（C(14)DMAO）在水溶液中结合，制备了具有非常大纵横比的自组装纳米管和未展开的纳米带。采用负染色透射电子显微镜（TEM）、场发射扫描电子显微镜（FE-SEM）、原子力显微镜（AFM）和低温透射电子显微镜（cro -TEM）对自组装的纳米管和纳米带进行了详细的表征。得到纳米管形成的最佳浓度比R = c(A6D)/c（C14DMAO）为1:8。通过傅里叶变换红外（FT-IR）和圆二色性（CD）测量，证明了纳米管和纳米带中存在β -片和随机线圈结构。基于这些结果，我们提出了自组装纳米结构的形成机制。特别是在8 mmol L-1 A(6)D/32 mmol L-1 C(14)DMAO纳米带上合成了直径为6.5 +/- 1.1 nm的金纳米粒子，在8 mmol L-1 A(6)D/64 mmol L-1 C(14)DMAO纳米管上合成了直径为6.8 +/- 1.5 nm的金纳米粒子，主要在纳米带表面或纳米管壁上观察到。此外，通过紫外-可见光谱测量，在520 nm处发现了Au纳米颗粒/纳米管和Au纳米颗粒/纳米带的特征峰。
Self-assembled structures such as nanotubes, nanobelts, nanofibers, and nanovesicles of surfactant-like peptides were obtained in water because of electrostatic interactions, hydrogen bonding, hydrophobic interactions and/or other weak interactions between peptide molecules. In this paper, we firstly prepared self-assembled nanotubes with very large aspect ratio and unfolded nanobelts by combining a peptide Ac-AAAAAAD-NH2 (A(6)D) with a zwitterionic surfactant, tetradecyldimethylaminoxide (C(14)DMAO), in aqueous solution at room temperature. The self-assembled nanotubes and nanobelts were characterized by negative-stained transmission electron microscopy (TEM), field emission-scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), and cryo-TEM in detail. The optimal concentration ratio, R = c(A6D)/c(C14DMAO), of nanotube formation was obtained to be 1 : 8. beta-Sheet and random coil structures were proved to co-exist in both nanotubes and nanobelts by Fourier transform infrared (FT-IR) and circular dichroism (CD) measurements. Based on these results, we proposed the formation mechanism of the self-assembled nanostructures. Particularly, Au nanoparticles with diameter of 6.5 +/- 1.1 nm from nanobelts of 8 mmol L-1 A(6)D/32 mmol L-1 C(14)DMAO and 6.8 +/- 1.5 nm from nanotubes of 8 mmol L-1 A(6)D/64 mmol L-1 C(14)DMAO were synthesized, and mainly observed on the nanobelt surfaces or the nanotube walls. Moreover, the Au nanoparticles/nanotubes and Au nanoparticles/nanobelts were proved via UV-vis measurements by the characteristic peaks at around 520 nm.