Label-Free SERS Fingerprinting for Chiral Discrimination Using Chiral Two-Dimensional Superlattice

Chiral discrimination is crucial in chiral synthesis, pharmaceuticals, and biology. Although surface-enhanced Raman scattering (SERS) provides highly sensitive molecule-specific vibrational data, existing approaches depend on indirect detection involving supplementary selectors, impeding clear and versatile chiral discrimination. Here, we report the direct label-free SERS sensing of different biologically prominent enantiomers with a two-dimensional transition metal dichalcogenide, such as TaS₂, based chiral superlattice to produce enantiospecific molecular fingerprints. The clear enantiodiscrimination between a model chiral pair of l- and d-glucose is achieved with a detection limit of 8 × 10^–10 M. In addition, noninvasive identification of l- and d-glucose in actual saliva samples and multiplex quantification of enantiomeric ratios with superior predictive accuracy are accomplished.