1. Ultrasensitive Nucleic Acid Assay Based on Cyclometalated Iridium(III) Complex with High Electrochemiluminescence Efficiency
- Author
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Nan Zhang, Yixiang Cheng, Zhi-Hong Xu, Hong-Yuan Chen, Jing-Juan Xu, Hang Gao, and Wei Zhao
- Subjects
chemistry.chemical_element ,Biosensing Techniques ,Iridium ,010402 general chemistry ,01 natural sciences ,Analytical Chemistry ,law.invention ,chemistry.chemical_compound ,Coordination Complexes ,law ,Humans ,Electrochemiluminescence ,Electrodes ,Detection limit ,Molecular Structure ,010401 analytical chemistry ,Electrochemical Techniques ,Combinatorial chemistry ,Cathode ,0104 chemical sciences ,Anode ,MicroRNAs ,chemistry ,Luminescent Measurements ,Electrode ,Luminophore ,Biosensor - Abstract
This work developed a sensitive electrochemiluminescence (ECL) biosensor based on a cyclometalated iridium(III) complex ((bt)2Irbza), which was synthesized for the first time. Annihilation, reductive-oxidative, and oxidative-reductive ECL behaviors of (bt)2Irbza were investigated, respectively. The oxidative-reductive ECL intensity was the strongest compared with the other two, which showed 16.7 times relative ECL efficiency compared with commercial [Ru(bpy)3]2+ under the same experimental conditions. Therefore, an ECL biosensing system with (bt)2Irbza as the anodic luminophore was established for miRNA detection based on a closed bipolar electrode (BPE). Combined with both steric hindrance and catalytic effects induced by hemin/G-quadruplex in the cathodic reservoir of BPE that changed the Faraday current of the cathode and thus mediated the ECL intensity of (bt)2Irbza in the anode of BPE, the ECL sensor stated an ultrahigh sensitivity for microRNA (miRNA-122) analysis with a detection limit of 82 aM.
- Published
- 2020