Novel ABEI/Dissolved O₂/Ag₃BiO₃ Nanocrystals ECL Ternary System with High Luminous Efficiency for Ultrasensitive...

Herein, a ternary electrochemiluminescence (ECL) sensing platform with high luminous efficiency was established for ultrasensitive bioanalysis of the microRNA-21 (miR-21) from cancer cell based on N-(aminobutyl)-N-(ethylisoluminol) (ABEI) as ECL emitter, dissolved O₂ as coreactant, and silver bismuth oxide nanocrystals (Ag₃BiO₃ NCs) as coreaction accelerator. Specifically, a novel coreaction accelerator Ag₃BiO₃ NCs was introduced into the ABEI/dissolved O₂ system to form an ECL ternary system, which could promote the reduction of dissolved O₂ to generate great deal of superoxide anion radical (O₂^•-), reacting with the ABEI to dramatically enhance the ECL performance. Simultaneously, a small amount of target miR-21 could trigger a one-step DNA self-assembly to form the DNA nanonet for embedding abundance ABEI with the assistance of doxorubicin hydrochloride (Dox), realizing the high-intense ECL response. Furthermore, owing to the thin-layer and porous structure, the obtained DNA nanonet could shorten the electron-transfer path of the ternary ECL system to reduce the energy loss, further improving the sensitivity of the sensing platform. As expected, the developed ECL sensing platform of miR-21 detection manifested prominent sensitivity with a low detection limit of 7.1 aM in the concentration of miR-21 range from 10 aM to 100 pM. Satisfactorily, the proposed sensing platform was triumphantly applied to detect miRNA in tumor cell lysates. Consequently, the designed strategy broadened the application of ABEI in biological analysis and hewed out a new path to establish the ECL ternary system with high luminous efficiency.