Chiral Nanozyme for Highly Enantioselective Detection of 3,4-Dihydroxy-D/L-phenylalanine

Enantioselective sensing of 3,4-dihydroxyphenylalanine (DOPA) enantiomers is highly significant in biology and pharmaceutics, yet developing sensors with high enantioselectivity and analyte-specific output signals remains challenging. In this study, we constructed an L-cysteine (Cys)-Fe 2+ nanozyme through self-assembly of L-Cys and Fe 2+ . This nanozyme exhibited efficient peroxidase-like activity, with a K cat value of 2.1 × 10 −9 M·s −1 ·µg −1 toward 3,3“,5,5”-tetramethylbenzidine (TMB). When using D/L-DOPA as a substrate, we observed higher catalytic efficiency for L-DOPA than for D-DOPA, with a selectivity factor of 1.6. Mechanistic studies revealed that this enantioselectivity originates from the preferential adsorption of D-DOPA over L-DOPA on the nanozyme surface, which impedes the oxidation kinetics by blocking substrate access to the active sites. These chirality-specific changes induced in UV–vis absorption during catalysis enabled the establishment of analyte-specific calibration curves for D-DOPA, L-DOPA, and enantiomeric compositions in D/L-DOPA mixtures, achieving highly enantioselective sensing of DOPA enantiomers. This sensing platform demonstrated high sensitivity (limit of detection: 3.6 µM), excellent selectivity, and significant potential for practical applications. These findings provide novel insights for developing superior enantioselective sensors with high accuracy. Graphical Through the self-assembly of L-cysteine (Cys) and Fe 2+ , we constructed a novel chiral L-Cys-Fe 2+ nanozyme. This nanozyme achieved high enantioselectivity in discriminating 3,4-dihydroxy-D/L-phenylalanine (D/L-DOPA) due to enantioselective adsorption. This approach constitutes a promising new platform for reliable enantiomer detection.