rGO-based porous structure modified by PPy/β-CD for 3D electrochemical chiral sensor

Chiral discrimination is crucial in medicine, food, and materials science. Herein, we report a novel electrochemical chiral sensor with a three-dimensional (3D) porous interface integrating chirality, conductivity, and porosity for efficient discrimination of tryptophan (Trp) enantiomers. The 3D porous reduced graphene oxide (p-rGO) film with enhanced nanosheet d-spacing and surface area is fabricated via a low-cost, adjustable self-assembly process, followed by electrochemical reduction. Polypyrrole (PPy) and β-cyclodextrin (β-CD) are co-deposited onto the p-rGO framework to construct the chiral sensing interface. The resulting p-rGO/PPy/β-CD electrode exhibits high enantioselectivity, enabling separate detection of D- and L-Trp and quantification of L-Trp in racemic mixtures. The superior recognition performance is attributed to the synergistic effects of the components: β-CD provides chiral cavities and hydrogen-bonding sites, PPy enhances π-π interactions and charge transfer, and p-rGO promotes electron transport and molecular adsorption. Theoretical simulations further reveal stronger hydrogen-bonding and binding energies between β-CD-PPy and L-Trp compared to D-Trp, confirming the experimentally observed selectivity. The sensor also demonstrates excellent reproducibility, stability, anti-interference ability, and applicability to real sample analysis. This work presents a general strategy for designing 3D-structured chiral sensors with high sensitivity and selectivity, highlighting the potential of integrating conductive, porous, and chiral materials for advanced electrochemical sensing platforms.