Chiral-Induced Surface-Enhanced Raman Optical Activity on a Single-Particle Substrate.

Abstract

Surface-enhanced Raman optical activity (SEROA) is a promising method for analyzing chiral molecules' molecular chirality and structural changes. However, conventional SEROA measurements face challenges related to substrate stability, signal uniformity, and interference from electronic circular dichroism (ECD). Therefore, in this study, we present a uniform and stable substrate for SEROA measurements by utilizing Au nanoparticles on the Au nanofilm structure to confine hotspots to the film-particle junctions and minimize ECD interference. This method also uses the induction of chirality from chiral molecules to achiral molecules to overcome the limitation of chiral molecules in SEROA measurements, specifically their lower signal efficiency. Successful chirality transfer is demonstrated through distinguishable SEROA signals when the l/d-alanine mixture is present. Enantiomeric discrimination of different l/d-alanine ratios was achieved with linear responses in the circular intensity difference (CID). Altogether, the proposed chiral-induced SEROA on the AuNP_on_AuNF substrate shows promising potential for detecting and characterizing structural changes in biomolecules, thus making it a valuable tool for various research applications.