A dual-OECT array sensor for discriminating and detecting fluoroquinolone antibiotics using simplified electrode modification

The accurate and rapid detection of fluoroquinolone antibiotics (FQs) is crucial, yet their structural homology often leads to cross-reactivity that compromise accuracy. Herein, we designed a poly(3,4-ethylenedioxythiophene) doped with a poly(styrenesulfonate) (PEDOT:PSS)-based dual-channel organic electrochemical transistor (OECT) array on a flexible, low-cost polyimide substrate. By leveraging the synergistic catalysis of single-walled carbon nanotubes (SWCNTs) and gold nanoparticles (AuNPs), effective discrimination of three FQs was achieved using gate electrodes modified with only two Nafion/SWCNTs/AuNPs composites, differing solely in AuNP mass fraction—this significantly simplifies fabrication for an electronic tongue system (ETS). Aided by principal component analysis (PCA), the system discriminates and quantifies ofloxacin (OFL), levofloxacin (LEV), and ciprofloxacin (CIP) across a wide concentration range of 0.4–1000 μM, with limits of detection (LODs) of 0.32–0.40 μM, while exhibiting excellent selectivity, anti-interference, consistency, stability, and rapid response. The comprehensive performance of this platform establishes a practical foundation for portable FQ sensing in environmental and clinical applications. Graphical abstract