Unique role of non-mercapto groups in thiol-pinning- mediated Ag growth on Au nanoparticles

• Published in: Nano research Vol. 11; no. 2; pp. 614 - 624
• Main Authors: Chen, Jiaqi, Yan, Jiao, Chen, Yuandong, Hou, Shuai, Ji, Yinglu, Wu, Xiaochun
• Format: Journal Article
• Language: English
• Published: Beijing Tsinghua University Press 01.02.2018; Springer Nature B.V
• Subjects: Amino acids; Atomic/Molecular Structure and Spectra; Biomedicine; Biotechnology; Chemistry and Materials Science; Circular dichroism; Condensed Matter Physics; Dichroism; Gold; Growth kinetics; Hybrid systems; Materials Science; Modulation; Molecular structure; Nanoparticles; Nanospheres; Nanostructure; Nanotechnology; Research Article; Silver; Thiols; 生长动力学;Ag;Au;组织;相互作用;半胱氨酸;氨基酸;调整; surface mediated; thiol modification; cysteine detection; accelerated overgrowth
• ISSN: 1998-0124; 1998-0000
• DOI: 10.1007/s12274-017-1666-4

Owing to the strong affinity of thiols to Au and Ag, they are often employed to modify the surfaces of nanoparticles （NPs）. Recently, these strong ligand-interface interactions have been employed to control NP growth, and this technique has emerged as a unique modulation strategy for creating unconventional plasmonic hybrid nanostructures. In these systems, the roles of the non-mercapto components of the thiol molecules and their structures are still unknown. Therefore, we herein present our investigation into this phenomenon. Primary amino （-NH2） groups in thiols are found to play a key role in regulating growth kinetics, i.e., in accelerating Ag deposition on Au NPs. The -NH2 groups are thought to bring Ag ions to the particle surface by coordinating to them, and thereby assist their reduction. The effect of molecular structure is non-trivial and thus provides the possibility of selective thiol detection. Based on the dependence of kinetic modulation on the non-mercapto components and molecular structures of molecules, we demonstrate the highly sensitive and specific detection of cysteine （limit of detection： 6 nM） in a mixture of 19 natural amino acids based on Ag growth on Au nanospheres. In addition, based on this modulation effect, we reveal the entrapping of chiral thiols within the growth layer through their plasmonic circular dichroism （PCD） responses. We believe that thiol-based growth regulation has great potential for creating plasmonic nanostructures with novel functionalities.