Chiral Interface Fabricated via L-Glutamic Acid-Assisted Electrodeposition and Sodium Alginate Self-Assembly for Trp Discrimination

The development of enantioselective sensing platforms combining operational simplicity with high efficiency remains a persistent challenge in interdisciplinary fields spanning biochemical analysis, pharmaceutical development, and clinical diagnostics. In this study, we report a novel approach to construct a P-L-Glu/SA/GCE chiral sensor based on L-glutamic acid (L-Glu) electrodeposition and sodium alginate (SA) self-assembly on glassy carbon electrodes (GCE) for the electrochemical recognition of tryptophan (Trp) enantiomers. Comprehensive characterization through Fourier-transform infrared spectroscopy(FT-IR), scanning electron microscopy(SEM), and electrochemical impedance spectroscopy confirmed the successful fabrication of an interfacial architecture featuring distinctive lamellar nanostructures with micrometer-scale curvature, reminiscent of bivalve shell morphologies. The maximum peak current ratio of D-Trp to L-Trp (ID/IL) reached 3.27 at the P-L-Glu/SA/GCE interface, determined by differential pulse voltammetry (DPV) method. There was a good linear relationship between the peak current and Trp enantiomer concentration across the 5-150 μM concentration range, with detection limits of 0.13 μM for D-Trp and 0.33 μM for L-Trp. Intriguingly, the P-L-Glu/SA/GCE chiral interface also realized chiral recognition of D-Trp and L-Trp via contact angle measurements. Finally, we demonstrated the accurate detection of the ratio of L/D-Trp in non-racemic mixtures using our P-L-Glu/SA/GCE interface, showing its potential for practical applications.