Portable dual-color bipolar electrode electrochemiluminescence biosensor array for simultaneous detection and imaging...

Rapid and sensitive detection of diverse trace bacteria in seawater faces scientific challenges. This work developed a color-potential-spatial highly-resolved bipolar electrode (BPE) electrochemiluminescence (ECL) array sensor for detection and imaging of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Herein, we introduced Agm/ATT-Au NCs and BiOI/Ru (bpy)₃²⁺ as new dual-color ECL probes, and Fe single-atom catalysts (Fe-SACs) as high-performance electrocatalysts to catalyze reduction of H₂O₂, generating an enhanced faradaic current that significantly amplifies ECL signal and improves imaging resolution. Moreover, we adopted a unique driving-voltage to control BPE-polarity change, enabling time-resolved activation of ECL materials at cathode or anode. This realized simultaneous crosstalk-free ECL detection and dual-color imaging of dual-targets. Well C emitted green light during positive potential scanning, and Well D emitted red light during negative scanning. In the presence of target bacteria, aptamer binding triggered quantitative release of l-cysteine (L-Cys) from mesoporous silica, which then bound to active sites of Fe-SACs and blocked catalytic effect, decreasing ECL signal for detection and imaging of E. coli (channel 1) and S. aureus (channel 2). This work provides a solution for simultaneous ECL analysis and multi-color imaging, opening new avenues for rapid, sensitive, and high-throughput detection of multiplex marine pathogens.