Amino Acid-Intercalated LDH as a Chiral Nanozyme for Dual-Mode Enantioselective Catalysis and Recognition

Designing a nanozyme with high enantioselectivity and efficient catalytic activity is of great significance in enantioselective analysis and asymmetric catalysis. In this work, chiral cysteine-inserted iron/cobalt layered double hydroxide nanozymes (Cys-LDH) were synthesized. The l-configuration LDH nanozyme (l-Cys-LDH) displayed stronger catalytic ability for the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) by H₂O₂, and exhibited higher recognition ability toward tryptophan (Trp) isomers than d-configuration LDH. The identification of l-Cys-LDH toward Trp enantiomers was achieved according to the absorbance ratio (2.75) in the colorimetric mode and the peak potential deviation (44 mV) and impedance change (647 Ω) in the electrochemical mode. This dual-mode sensor can effectively detect the Trp enantiomer with a detection limit of 24 μM for the colorimetric mode and 0.63 μM for the electrochemical mode. This work provides references for further application of nanozymes in enantioselective recognition and catalysis.