A newly developed chiral Ru-phe probe for highly sensitive enantioselective detection of tryptophan.

A chiral ruthenium probe (Ru-phe) for determination of amino acids was constructed by conjugating L-phenylalanine to a Ru-MOF precursor via EDC/NHS activation. The stereogenic center and aromatic side chain of L-Phe establish a chiral microenvironment that facilitates π–π stacking and hydrophobic interactions with tryptophan, thereby enabling efficient enantioselective recognition. The Ru-phe electrochemiluminescence (ECL) sensing platform achieved broad linear quantification ranges—0.1 nM – 1 mM for L-Trp and 10 nM – 1 mM for D-Trp. The detection limits were 0.06 nM for L-Trp and 13 nM for D-Trp. Moreover, the method showed strong reproducibility in human serum samples, with relative standard deviations (RSDs) of 0.9–1.8% for L-Trp. Machine-learning-assisted classification further improved enantiomer discrimination accuracy to 96%. Overall, this work introduces an efficient and highly sensitive ECL approach that enables practical enantiomeric determination of tryptophan, offering strong potential for clinical monitoring.