Highly selective recognition and ultrasensitive quantification of enantiomers

The ability to recognize and quantify the molecular chirality of enantiomers at the nanolevel in biological systems constitutes the basis of many critical areas for specific targeting in drug development and metabolite probing. Plasmonic nanoparticle dimers exhibit circular dichroism effects at visible wavelengths, amplifying the chiral signal of chiral molecules. We demonstrate the self-assembly of plasmonic chiroptical dimers through multibody attractive forces mediated by cysteine, which amplified the plasmonic chirality of enantiomers using enantiomeric cysteines (l and d), and achieved chiral recognition and a quantitative chiroptical sensing platform, with a detection limit of 20 pM level for l-cysteine. The versatility of nanoparticle dimers with customized chiroptical response opens up the avenue for adaptation of the plasmonic chiroptical platform for the drug development and proteomic profiling of metabolites.