L@HOF-101-Based Two-Potential/Color-Distinguished Zero-Background Bipolar-Electrode Electrochemiluminescence Biosensor for Synchronous Imaging and Detection of Dual Targets.

A novel electrochemiluminescence (ECL) luminophore, L@HOF-101, was prepared for the first time, which generates high-intensity ECL signals and dual-color imaging under positive and negative potential scanning. By further introducing a high-performance catalytic probe, Pt/CoSAs@NC, a zero-background bipolar-electrode (BPE)-ECL sensing system was developed for synchronous potential-distinguished signal detection and two-color imaging analysis of aflatoxin B1 (AFB1) and deoxynivalenol (DON). The L@HOF-101 luminophore was pre-modified in reaction cells c and d. In the presence of the two targets, two specific DNA outputs are simultaneously generated. Through the binding of capture probes with these output strands, the catalytic probes are precisely immobilized in reaction cells a and b of the BPE; the electron transfer efficiency at the BPE is significantly enhanced, resulting in a substantial ECL signal amplification effect. During positive potential scanning, the c hole is positively polar. As large quantities of Pt/CoSAs@NC are introduced onto the electrode by the outputs, the ECL signal and green mobile phone imaging emitted by L@HOF-101 are tremendously enhanced for AFB1 detection and imaging assays. During negative potential scanning, the d hole is positively polar. Similarly, under the action of Pt/CoSAs@NC, the ECL signal and blue imaging of L@HOF-101 are much enhanced to detect DON. In the absence of the targets, due to the efficient regulation of the electron transfer process by Pt/CoSAs@NCs, the biosensor exhibits nearly zero-background signals. This work not only exploits a new dual-color, high-resolution ECL imaging sensor but also provides a reliable, highly sensitive zero-background analytical platform for the simultaneous rapid detection of multiple targets.