Interfacial engineering for enantioselective electrochemical sensing of tryptophan: materials, recognition...

The enantioselective detection of biologically active molecules is a vital analytical challenge, particularly for tryptophan (Trp), where the L- and D-enantiomers exhibit distinct physiological functions despite their near-identical properties. Electrochemical (EC) sensing offers a powerful solution, providing high sensitivity and miniaturization potential suitable for in situ monitoring. This review examines the state-of-the-art in EC chiral sensing of Trp, focusing on the integration of functional modifiers such as cyclodextrins (CDs), metal-organic frameworks (MOF), polymers/biopolymers, biomolecules and functional nanomaterials. We deconstruct the molecular recognition mechanisms focusing on enantioselectivity, including hydrogen bonding, π-π interactions, and steric complementarity, supported by theoretical modelling and experimental benchmarking. Furthermore, we evaluate emerging trends including microfluidic integration and AI-assisted signal processing while critically assessing current limitations in sensor stability and reproducibility. By linking interfacial mechanisms to sensing performance, this work provides comprehensive guidance for the rational design of EC platforms for point-of-care and environmental applications.