講演情報
[9a-PA4-26]Role of Au-glutathione Coordination Species in the Formation of Chiral Au Nanostructures and Enantioselective SERS Sensing
〇(D)Junhe WANG1, Tianji Zhang1, Takuya Nakanishi1, Yusuke Yamauchi2,3,4, Toru Asahi1, Kenta Nakagawa1 (1.Waseda University, 2.Nagoya University, 3.University of Queensland, 4.NIMS)
キーワード：
Chirality、Chiroptical properties、Chiral sensing
Chiral plasmonic nanostructures have attracted considerable attention owing to their unique chiroptical properties and potential applications in enantioselective sensing. Although various chiral gold nanostructures have been synthesized using chiral molecules as structure-directing agents, there has been rare research on the synthesize of chiral nanostructure via electrodeposition. In particular, the evolution of gold coordination species in electrolyte solutions prior to electrodeposition and its relationship to the resulting chiral nanostructures have not been fully clarified. In this study, the corals Au substrates were synthesized by an electrodeposition method using soft-template block copolymers, and chiral Au nanostructures were synthesized on corals Au substrates by electrodeposition using the thiol-containing peptide GSH as a chiral additive. In our previous work, chiral Au nanostructures were successfully synthesized using cysteine-assisted electrodeposition. Here, GSH, another thiol-containing chiral molecule, was employed to gain deeper insight into the formation process of chiral Au nanostructures. The evolution of Au–GSH coordination species and their role in directing the formation of chiral Au nanostructures were investigated using spectroscopic techniques. Time-dependent spectroscopic analyses reveled that the reaction between GSH and HAuCl4 produces a series of gold coordination species prior to electrodeposition. Spectroscopic analyses revealed the formation of Au-GSH complexes accompanied by the reduction of Au ions. The evolution of these coordination structures strongly influences the formation of chiral Au nanostructures, resulting in intense mirror-image plasmonic CD responses. Furthermore, chiral Au/coral-like Au substrates were constructed and exhibited enhanced SERS activity. The substrates also showed enantioselective responses toward chiral amino acid phenylalanine, demonstrating their potential for chiral molecular sensing.