Amino-acid- and peptide-directed synthesis of chiral plasmonic gold nanoparticles
Amino-acid- and peptide-directed synthesis of chiral plasmonic gold nanoparticles
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DOI：
10.1038/s41586-018-0034-1
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发表时间：
2018-04-19
期刊：
影响因子：
64.8
通讯作者：
Nam, Ki Tae
中科院分区：
文献类型：
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作者：
Lee, Hye-Eun;Ahn, Hyo-Yong;Nam, Ki Tae
了解分子中的手性或手性很重要，因为在许多生化反应中观察到的对映选择性(1)，以及具有特殊光操纵能力的手性超材料的最新发展，例如偏振控制(2-4)、负折射率(5)和手性传感(6)。利用光刻(7)和分子自组装(8-11)等纳米制造技术已经制备了手性纳米结构，但大规模和简单的三维手性结构制造方法仍然是一个挑战。在这一点上，手性转移代表了一种更简单和更有效的手性形态控制方法(12-18)。虽然一些研究(18，19)描述了分子手性向微米级螺旋陶瓷晶体的转移，但这项技术还没有应用于数百纳米级的金属纳米颗粒。在这里，我们开发了一种合成手性金纳米颗粒的策略，包括使用氨基酸和多肽来控制纳米颗粒的光学活性、手性和手性等离子体共振。获得这种手性结构的关键要求是形成高米勒指数表面({hkl}，h不等于k不等于L不等于0)，这些表面本质上是手性的，这是由于纳米颗粒在生长过程中存在‘扭结’位(20-22)。手性组分在纳米粒子的无机表面以及氨基酸和多肽中的存在导致这些元素之间的界面上的对映选择性相互作用；这些相互作用导致纳米粒子的不对称演化和由高度扭曲的手性元素组成的螺旋面形态的形成。我们生长的金纳米颗粒显示出很强的手性等离子体光学活性(不对称因子为0.2)，即使在溶液中随机分散也是如此；这一观察结果得到了理论计算和宏观颜色变化的直接可视化的支持。我们预计，我们的策略将有助于合理设计和制造用于等离子体超材料应用的三维手性纳米结构。
Understanding chirality, or handedness, in molecules is important because of the enantioselectivity that is observed in many biochemical reactions(1), and because of the recent development of chiral metamaterials with exceptional light-manipulating capabilities, such as polarization control(2-4), a negative refractive index(5) and chiral sensing(6). Chiral nanostructures have been produced using nanofabrication techniques such as lithography(7) and molecular self-assembly(8-11), but large-scale and simple fabrication methods for three-dimensional chiral structures remain a challenge. In this regard, chirality transfer represents a simpler and more efficient method for controlling chiral morphology(12-18). Although a few studies(18,19) have described the transfer of molecular chirality into micrometre-sized helical ceramic crystals, this technique has yet to be implemented for metal nanoparticles with sizes of hundreds of nanometres. Here we develop a strategy for synthesizing chiral gold nanoparticles that involves using amino acids and peptides to control the optical activity, handedness and chiral plasmonic resonance of the nanoparticles. The key requirement for achieving such chiral structures is the formation of high-Miller-index surfaces ({hkl}, h not equal k not equal l not equal 0) that are intrinsically chiral, owing to the presence of 'kink' sites(20-22) in the nanoparticles during growth. The presence of chiral components at the inorganic surface of the nanoparticles and in the amino acids and peptides results in enantioselective interactions at the interface between these elements; these interactions lead to asymmetric evolution of the nanoparticles and the formation of helicoid morphologies that consist of highly twisted chiral elements. The gold nanoparticles that we grow display strong chiral plasmonic optical activity (a dissymmetry factor of 0.2), even when dispersed randomly in solution; this observation is supported by theoretical calculations and direct visualizations of macroscopic colour transformations. We anticipate that our strategy will aid in the rational design and fabrication of three-dimensional chiral nanostructures for use in plasmonic metamaterial applications.