Aerosol Jet Printed Ag Micropillar Arrays Coupled with PEDOT:PSS for High-Performance Electrochemical Sensing of Niclosamide

In this study, an aerosol-jet-printed silver micropillar array was introduced onto the surface of a screen-printed carbon electrode (SPCE) and further coated with a poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) functional film, yielding a three-dimensional hierarchical electrode for high-performance electrochemical detection of niclosamide (NA). The silver micropillar arrays form a three-dimensional microelectrode network on the working electrode surface, where the pillar tops and sidewalls markedly increase the electrochemically active area and facilitate mass transport toward the electrode interface, thereby enhancing analyte flux and amplifying the Faradaic response. In addition, PEDOT:PSS as a mixed ionic-electronic conductor, establishes a continuous and stable reaction interface on the silver-pillar scaffold, which not only improves interfacial wettability and charge/ion transport but also promotes interfacial enrichment of NA via its functionalized polymer network. Benefiting from the synergistic effects of three-dimensional structural amplification and conductive-polymer-mediated interfacial regulation, the fabricated Ag@PEDOT:PSS/SPCE sensor exhibits a good linear response over 0.01-15 μM with a limit of detection as low as 1.73 nM. Meanwhile, the sensor demonstrates excellent repeatability, reproducibility, and anti-interference performance, and it was successfully applied to the quantitative determination of NA in tap water and oolong tea samples with satisfactory recoveries and accuracy, indicating strong potential for practical applications.