We developed a simple and versatile method to fabricate metal nanoparticle-integrated microelectrode arrays via in situ reduction on polydopamine microarrays patterned by microcontact printing. The resulting AuNPs array sensor exhibited significantly enhanced current density and a low detection limit of 2.5 µM for nitrite, with successful application to food samples. This platform features tunable geometry and broad electrochemical applicability.

Abstract

Microelectrode arrays (MEAs) offer excellent performance but are often limited by complex fabrication and high costs. Here, we present a simple, universal method for constructing metal nanoparticle (MNP) microarray electrodes—Au, Ag, and Pd—via in situ reduction on polydopamine (PDA) microarrays patterned by microcontact printing (µCP). Because each microdisk allows for nearly independent spherical diffusion, the system benefits from significantly enhanced mass transport conditions. Using AuNPs microdisk array electrodes, nitrite determination was achieved, which demonstrates a 4-fold enhancement in current density and improved sensitivity (LOD = 2.5 µM) compared to conventional randomly modified electrodes. The sensor also demonstrated successful detection of nitrite in real food samples. This versatile platform allows tunable array geometry and composition, offering broad potential for electroanalytical and electrocatalytic applications.