In
this study, a ternary electrochemiluminescence (ECL) sensing
platform coupled with a multiple signal amplification strategy was
proposed for ultrasensitive detection of miRNA-141. The initial signal
amplification was achieved via three-dimensional reduced graphene
oxide (3D-rGO)@Au nanoparticles (NPs) to form an excellent conductive
layer. Then, AuPd NPs as a coreaction accelerator was introduced into
the N-(4-aminobutyl)-N-(ethylisoluminol)
(ABEI)–H2O2 system to facilitate the
transformation from H2O2 to excess superoxide
anion radicals (O2
•–), which further
amplified the ECL emission of ABEI, leading to a significant increase
of the ECL signal. Meanwhile, in the presence of miRNA-141 and T7
Exonuclease (T7 Exo), the self-assembled DNA swing arm can be driven
to walk autonomously. The DNA walker reaction could result in the
release of numerous labeled luminophores, which could react to achieve
an extremely weak ECL signal. Surprisingly, the established ECL sensor
platform for the detection of miRNA-141 demonstrated excellent sensitivity
with a low detection limit of 31.9 aM in the concentration range from
100 aM to 1 nM. Consequently, the designed strategy greatly improves
the luminous efficiency of the ternary ECL system and provides a special
approach for the detection of nucleic acids and biomarkers in clinical
and biochemical analysis.