title: Interband Absorption Enhanced Optical Activity in Discrete Au@Ag Core-Shell Nanocuboids: Probing Extended Helical Conformation of Chemisorbed Cysteine Molecules.
abstract: Detailed understanding of the interaction between a chiral molecule and a noble metal surface is essential to rationalize and advance interfacial self-assembly of amino acids and metal-mediated anchoring of proteins. Here we demonstrate that individual Au@Ag core-shell nanocuboids can serve as a plasmonic reporter of an extended helical network formed among chemisorbed cysteine molecules, through generating an interband absorption enhanced, Ag-surface-exclusive circular dichroism (CD) band in the UV region. The observed unusual, strong CD response in the hybrid Au@Ag-cysteine system can be used to probe in real time conformational evolution and structural rearrangement of biomolecules in general and also monitor the interfacial interaction between a metal surface and an adsorbed molecule, opening up the possibility of using Ag nanostructures as promising stereochemically attuned nanosensors.
authors.affiliation: Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong, China.
authors.forename: Zhi Yong
authors.initials: ZY
authors.lastname: Bao
authors.affiliation: Institute of Applied Physics and Computational Mathematics, Beijing, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong, China.
authors.forename: Yong-Liang
authors.initials: YL
authors.lastname: Zhang
authors.affiliation: Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong, China.
authors.forename: Jijun
authors.initials: J
authors.lastname: He
authors.affiliation: Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong, China.
authors.forename: Jiyan
authors.initials: J
authors.lastname: Dai
authors.affiliation: Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China.
authors.forename: Chi-Tung
authors.initials: CT
authors.lastname: Yeung
authors.affiliation: Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China.
authors.forename: Ga-Lai
authors.initials: GL
authors.lastname: Law
authors.affiliation: Department of Applied Physics, The Hong Kong Polytechnic University, Hong Kong, China.
authors.forename: Dang Yuan
authors.identifier: 0000-0002-8963-0193
authors.initials: DY
authors.lastname: Lei
keywords: circular dichroism; interband transition; metal nanostructures; optical activity; structural conformation