Ultrasound-promoted specific chiroptical sensing of cysteine in aqueous solution and cells

Abstract

The quantity and chirality of cysteine (Cys) are correlated with diseases and have crucial implications in physiology and pathology. A selective chiral sensor for Cys based on electronic circular dichroism and UV detection was developed, and the sensing reaction takes place rapidly in aqueous solution with the aid of ultrasound. This sensing approach can simultaneously determine the absolute optical purity and total concentration of Cys. The limit of detection is 0.25 μM, and the detection is not impeded by other naturally occurring amino acids or common biothiols. This method is simple to operate and has the advantages of fast detection, high sensitivity and selectivity, and the measurement error is no more than 4%, with application potential for high-throughput screening. A kit containing this sensor was prepared and successfully applied in a sensing study of cells and peptides containing N-terminal Cys residues to detect endogenous and exogenous Cys in cells and determine the absolute configuration of N-terminal Cys in polypeptides. This work has important application prospects for the study of Cys with the aim of diagnosing related diseases.