Dual-Modal Sensing of Enantiomeric Purity Using Chiral Au@Cu x S Nanoparticles

Abstract Enantiomeric discrimination is essential for a range of pharmacological and biochemical applications. Herein, we present a rational design of chiral Au@CuxS nanoparticles (NPs) that serve as a dual-modal sensing platform for determining enantiomeric purity. By synergizing the localized surface plasmon resonance (LSPR) of the Au core with the semiconducting properties of the CuxS shell, these NPs exhibit robust chiroptical activity alongside enhanced near-infrared (NIR)-responsive photocatalytic and photothermal performances. We demonstrate that enantioselective interactions between target chiral analytes with antioxidant capabilities, such as glutathione (GSH), tryptophan (Trp), aspartic acid (Asp), and cysteine (Cys), and the NP surfaces serve as mechanisms to modulate reactive oxygen species (ROS) generation and photothermal conversion. Specifically, the catalytic degradation of chromogenic substrates and the concomitant temperature increase are highly sensitive to the enantiomeric ratios of these analytes, which act as interfacial modulators. This dual-signal strategy enables rapid and accurate chiral discrimination in enantiomeric matrices, providing a versatile analytical platform and highlighting the potential of chiral plasmonic-semiconductor heterostructures in precise molecular recognition.