Artemisinin: a novel chiral electrochemiluminescence luminophore-assisted enantiospecific recognition and mechanism identification

Abstract

Exploring novel electrochemiluminescence (ECL) molecules with high efficiency and good stability in aqueous solutions is crucial for achieving highly sensitive detection of analytes. However, developing chiral luminophores with efficient ECL performance is still a challenge. Herein, we first uncover that artemisinin (ART), a well-known chiral antimalarial drug, features a strong ECL emission at 726 nm with the assistance of a co-reactant potassium persulfate (K₂S₂O₈), and an ECL efficiency of 195.3%, compared to that of standard Ru(bpy)₃Cl₂/K₂S₂O₈. Mechanistic studies indicate that the strong ECL signal of ART is generated when the excited state formed by the reduction of ART peroxide bonds and combination with persulfate returns to the ground state. Significantly, we found that the ECL sensor based on chiral ART could efficiently identify and detect chiral cysteine (Cys) through ECL signals, with a lower limit of detection of 3.7 nM for L-Cys. Density functional theory calculations and scanning electrochemical microscopy technology further confirm that the disparity in the ECL signals is attributed to the different affinity between chiral ART and D/L-Cys, resulting in distinct electron transfer rates. The study demonstrates a new role of ART in ECL investigation and for the first time, achieves the development of ART for the enantioselective recognition and sensitive detection of chiral substances. This will be of vital significance for ECL and chirality research.