Spatially decoupled dual-mode array for ECL-colorimetric detection of seafood pathogens via catalytic hairpin assembly and G-quadruplex

Spatial segregation via physically isolated units eliminated signal crosstalk. • Programmable scalable strategy enables broad adaptability for multiple pathogens. • Cascaded CHA and HCR achieved dual-signal amplification for higher sensitivity. • Screen-printed electrode arrays enable portable, rapid and stable detection. Seafood is a vital component of the global diet, yet it is highly susceptible to contamination by diverse pathogenic microorganisms during production and distribution, posing significant threats to public health. Herein, we report a novel dual-mode sensing array based on screen-printed electrodes (SPEs) for the simultaneous and rapid detection of multiple pathogenic bacteria in aquatic products via synergistic electrochemiluminescence (ECL) and colorimetric readouts. The spatially separated architecture, comprising distinct recognition, ECL, and colorimetric units, effectively circumvents signal interference. A target transduction system is established to recognize different targets and release a universal transducer strand B for following reactions. Upon target binding, AuNPs-H2/GT probes initiate a catalytic hairpin assembly (CHA) cascade, results in a dual function: it sequesters AuNPs-Ru(bpy) 3 2+ -labeled H1 probes to generate ECL signal, while concurrently releasing GT strands; triggers a hybridization chain reaction with G-quadruplex (G4)-forming hairpins in the separate colorimetric zone, yielding a vivid colorimetric response. By integrating the sensitivity of ECL with the broad linear dynamic range of colorimetry, and utilizing spatial separation to ensure specificity in real samples, this work presents an integrated, cost-effective, and portable platform. It provides a powerful tool for the rapid, visualized, and reliable monitoring of microbial hazards in seafood safety control. Spatially Decoupled Dual-Mode Array for ECL-Colorimetric Detection of Seafood Pathogens via Catalytic Hairpin Assembly and G-Quadruplex. Download: Download high-res image (97KB) Download: Download full-size image