Regenerable Electrochemical Sensing Enabled by Reversible Imine-Bond Chemistry

Abstract Sustainable electrochemical interfaces should retain their functionality during repeated use while minimizing material consumption, reagent input, and waste generation. However, most chemically modified electrodes remain single-use because surface-bound species and reaction products occupy active sites, necessitating repeated cleaning and reconstruction for subsequent use. To restore interfacial functionality and enable reuse, regeneration strategies based on chemical elution, electrochemical cleaning, photoactivation, and biomolecular displacement have been developed. Nevertheless, these approaches often require strongly acidic or alkaline media, competitive eluents, additional energy input, specialized components, or auxiliary reagents, thereby increasing operational complexity and potentially compromising interfacial integrity. Here, reversibility was directly encoded into the interface through dynamic imine (Schiff-base) covalent linkages, enabling mild and selective surface renewal. An aldehyde-functionalized conductive network was constructed by coupling 4-formylbenzoic acid with amino-functionalized multiwalled carbon nanotubes. Glutathione was employed as a model amine-containing molecule and reversibly captured through this dynamic covalent linkage. Subsequent Cu2+-mediated conversion produced a distinct Cu+ oxidation response. Mild treatment with pH 5.0 buffer restored the aldehyde-functionalized surface within 6 min, enabling at least 20 consecutive sensing-regeneration cycles without electrode reconstruction. Under optimized conditions, the platform exhibited a broad linear response and achieved a nanomolar-level limit of detection. By integrating molecular capture and release within the same dynamic covalent architecture, this work provides an interface-engineering route toward reusable electrochemical systems with reduced material and reagent inputs associated with repeated interface reconstruction.