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

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 O-2 as coreactant, and silver bismuth oxide nanocrystals (Ag3BiO3 NCs) as coreaction accelerator. Specifically, a novel co-reaction accelerator Ag3BiO3 NCs was introduced into the ABEI/dissolved O-2 system to form an ECL ternary system, which could promote the reduction of dissolved O-2 to generate great deal of superoxide anion radical (O-2(center dot-)), 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.