A Dual-Signal Electrochemiluminescence Sensor for Kanamycin Detection Based on Self-Enhanced Zr MOFs and Single Co-Reactant Competition Mechanism

The dual-signal output self-calibration mode reduces false positive or negative signals of electrochemiluminescence (ECL) aptamer sensors. A competitive dual-signal ECL platform was designed for ultrasensitive detection of kanamycin (KAN)using zirconium metal-organic frameworks (Zr MOFs) and Luminol as ECL emitters. To enhance the ECL efficiency, co-reactant (polyethyleneimine, PEI) was covalently bound to Zr MOFs to achieve the self-enhanced ECL. Based on the selective interaction between KAN and its aptamer, the Luminol/KAN/Zr MOFs-PEI "sandwich" structure was immobilized on the electrode surface. The competition for PEI between emitters increased the Luminol ECL signal and decreased the Zr MOFs ECL signal. The ratio in ECL signals between the two competitive emitters enabled the quantitative analysis of KAN, achieving a detection limit as low as 7.86 × 10-4 ng/mL. This study elucidated the synergistic mechanism between self-enhanceding ECL and ECL competition, offering a novel approach for constructing dual-signal ECL sensors using a single co-reactant.