Raman spectroscopic technologies for chiral discrimination: Current status and new frontiers

Chiral discrimination is crucial in drug safety, catalysis, materials science, and environmental sustainability, as enantiomers often exhibit distinct biological, chemical, and physical properties. Raman spectroscopic technologies have established efficient strategies for discriminating enantiomers through manipulating the Raman excitation and scattering light, as well as constructing chiral molecular recognition systems and chiral surface-enhanced Raman spectroscopy (SERS) substrates, which offer the advantages of non-destructive, label-free, and real-time analysis. This review systematically summarizes the principles and recent advances in Raman spectroscopic technologies for discriminating enantiomers. We begin by introducing the fundamental mechanisms and experimental progress of Raman optical activity (ROA), highlighting its importance in enantiomeric discrimination. Moving beyond the complex instruments used in ROA-based methods, we discuss critical breakthroughs in enantiomeric discrimination by combining plasmonic structures with conventional Raman spectrometers. The emerging strategies to discriminate enantiomers by both achiral and chiral plasmonic structures are summarized, with particular emphasis on the underlying mechanisms of chiral plasmonic structures in enantioselective SERS. Finally, we present the major challenges and future opportunities in this evolving field, providing insights into the future development directions.