Chiral recognition of amino acids based on cyclodextrin-capped quantum dots

A study described the synthesis of water-soluble and stable semiconductor CdSe/ZnS QDs (quantum dots) by using β-CD (cyclodextrin) and α-CD as surface-coating agents in a very simple sonochemical method. Their potential application as enantioselective fluorescent sensors for amino acids (AA) was investigated. The resulting water-soluble QD nanoparticles retain the optical properties of the original hydrophobic QDs. It was discovered that the CD-QDs allow the highly enantioselective fluorescent recognition of amino acids. Within a certain concentration range, one enantiomer of the chiral amino acid can enhance the fluorescence intensity of the CD-QDs, whereas the other enantiomer hardly affects the fluorescence. Such unusually high enantioselective responses thereby make these CD-QDs very attractive as fluorescent sensors in determining enantiometric compounds.