J Am Chem Soc. 2020 May 20;142(20):9158-9162. doi: 10.1021/jacs.0c03672. Epub 2020 May 11.
The plasmonic properties of silver nanoparticle (AgNP) arrays are directly controlled by AgNP size, shape, and spatial arrangement. Reported here is a strategy to prepare chiral AgNP arrays templated by two constitutionally isomeric aromatic peptide amphiphiles (APAs), and (K = -aroylthiooxime-modified lysine, = citrulline, and E = glutamic acid). In phosphate buffer, both APAs initially self-assembled into nanoribbons with a similar geometry. However, in the presence of silver ions and poly(sodium 4-styrenesulfonate) (PSSS), one of the nanoribbons () turned into nanohelices with a regular twisting pitch, while the other () remained as nanoribbons. Both were used as templates for synthesis of arrays of ∼8 nm AgNPs to understand how small changes in molecular structure affect the plasmonic properties of these chiral AgNP/APA hybrids. Both hybrids showed improved colloidal stability compared to pure AgNPs, and both showed enhanced sensitivity as surface-enhanced Raman spectroscopy (SERS) substrates for model analytes, with nanohelices showing better SERS performance compared to their nanoribbon counterparts and pure AgNPs.
银纳米颗粒（AgNP）阵列的等离子体特性可直接通过 AgNP 的尺寸、形状和空间排列来控制。本文报道了一种通过两种结构异构体芳香肽两亲物（APAs）制备手性 AgNP 阵列的策略，这两种两亲物分别是 和 （K = -酰基硫肟修饰的赖氨酸， =瓜氨酸，E = 谷氨酸）。在磷酸盐缓冲液中，两种 APA 最初都自组装成具有相似几何形状的纳米带。然而，在银离子和聚（4-苯乙烯磺酸钠）（PSSS）存在的情况下，其中一种纳米带（）转变成具有规则扭转螺距的纳米螺旋，而另一种（）仍保持纳米带状态。这两种纳米带都被用作合成约 8nm AgNP 阵列的模板，以了解分子结构的微小变化如何影响这些手性 AgNP/APA 杂化物的等离子体特性。与纯 AgNP 相比，这两种杂化物都显示出更好的胶体稳定性，并且都表现出作为表面增强拉曼光谱（SERS）基底对模型分析物的增强灵敏度，与纳米带相比，纳米螺旋显示出更好的 SERS 性能，而纯 AgNP 则没有。
