Selective voltammetric determination of labile copper in unpretreated wine samples using a synthetic fungal-mimicking...

The development of bioinspired sensing interfaces offers a sustainable strategy for trace metal monitoring in complex matrices. We report a synthetic, reproducible biomimetic membrane composed of chitosan, mannan, and curdlan that replicates the structural motifs and metal-binding functionalities of fungal cell walls. This interface is obtained via pH-assisted electrochemical deposition onto boron-doped diamond (BDD) electrodes, followed by stabilization with genipin vapors to ensure structural robustness in acidic environments. Morphological and compositional characterization (SEM/EDX, AFM, and EIS) confirmed the reversible and preferential coordination of copper ions within the polysaccharide framework. Using Differential Pulse Anodic Stripping Voltammetry (DPASV), the sensor achieved a limit of detection (LOD) of 0.0108 μM in aqueous media and 0.1 μM in red wine. While the platform also shows affinity for iron, the membrane exhibits a preferential response to copper in multi-metal solutions. consistent with the Irving-Williams series, acting as a protective barrier against polyphenolic fouling. When applied to unpretreated wine samples, the sensor effectively quantifies the direct speciation of labile copper fraction (135 nM), offering a sustainable and bioinspired alternative for assessing metal speciation and food quality.