Ternary Electrochemiluminescence System Based on Rubrene Microrods as Luminophore and Pt Nanomaterials as Coreaction Accelerator for Ultrasensitive Detection of MicroRNA from Cancer Cells

As the only endogenous coreactant in the electrochemiluminescence (ECL) system, the dissolved O2 was the ideal candidate due to the mild reaction and easy operation, but compared to S2O82-, the dissolved O2 with weaker redox activity suffers from the poor enhancement effect of the luminophore, which restricted the further application in bioanalysis. Here, a high-intense ECL signal was gained by the employing of Pt nanomaterials as a coreaction accelerator to generate more of the intermediate of dissolved O2 to promote the coreaction efficiency. On the basis of a new ternary ECL system of Pt nanomaterials as the coreaction accelerator, dissolved O2 as the coreactant, and a neotype rubrene microrods as the luminophore, an efficient "on-off-on" solid-state ECL switch platfrom was designed for ultrasensitive microRNA (miRNA) detection with a background reduction strategy of ferrocene-labeled single-stranded DNA (Fc-DNA) as a quencher. In the presence of miRNA 141, the Pt nanoparticles labeled hairpin (HP1/PtNPs) was opened to produce plenty of Pt nanoparticles labeled output DNA (S1/PtNPs) and release the miRNA-141 to participate in the next cycle. Then, the S1/PtNPs were captured on the surface of the electrode by the complementary strand to obtain the super "signal on" state with extremely high ECL signal. This novel solid-state ECL platform exhibited excellent sensitivity from 10 aM to 100 pM with a detection limit of 2.1 aM, which provided a new approach for ultrasensitive ECL bioanalysis.