Self-coreaction accelerator enhanced electrochemiluminescence system-based target-induced competitive assay for...

Paraquat (PQ) has gained significant attention in the fields of agricultural analysis and clinical diagnostics due to its efficient herbicidal properties and serious toxicity in humans even at low concentrations. Obviously, the quantification of PQ in plasma is essential for therapeutic management and clinical intervention in poisoning cases. Herein, we proposed a novel electrochemiluminescence (ECL) system with bifunctional nanomaterials as ECL emitter and coreaction accelerator simultaneously with significantly enhanced ECL emission efficiency, that was employed to structure a self-coreaction accelerator enhanced ECL system-based target-induced competitive assay for ultrasensitive analysis of PQ. The target PQ will cause it to compete with the PQ-conjugated DNA strands to bind with anti-PQ antibodies, resulting in a lower catalytic hairpin assembly frequency with a lower output of ferrocene-modified DNA strands (Fc-DNA) and lower inhibition on ECL emission. As a result, this proposed ECL biosensor performed a high sensitivity with a detection limit of 0.115 pg/mL for PQ in the range from 1 pg/mL to 1 μg/mL, generating high potential for PQ analysis in clinical samples. Importantly, this strategy could be conveniently extended to other small molecules by simply replacing the antibody that enrich current toolbox of small molecules analysis technologies, offering a broad prospect for applications in fields such as agricultural residue monitoring and clinical diagnosis.