Dual-potential ratiometric electrochemiluminescence microRNA bioassay based on inner reference probe and catalytic hairpin assembly

Abstract

Dual-signal ratiometric biosensors have drawn great attention due to their good reproducibility, reliability, and anti-interference ability in sensitive biosensing. Herein, we propose a dual-potential ratiometric electrochemiluminescence (ECL) biosensor based on an internal reference probe and catalytic hairpin assembly (CHA) signal amplification strategy. The cathodic ECL signal of Au-deposited graphitic carbon nitride nanosheets (Au-g-C3N4) was selected as the inner reference, while the anodic ECL response of luminol-H2O2 in solution was used as the reporter signal. After target recognition, Pt nanocluster-labeled DNA strands were introduced onto the surface of the electrode by DNA hybridization, effectively accelerating the production of reactive oxygen species (O2•–) and greatly enhancing the reporter signal with high catalytic activity. The ratio of ECL intensity between the enhanced anodic signal and stable cathodic signal varies with a good linear relationship to the logarithm of microRNA concentration during the detection procedure. Assisted by target-induced CHA signal amplification, this ratiometric ECL biosensor displayed favorable performance for the sensitive detection of microRNA-21 with build-in correction against circumventing fluctuations. The expression level of microRNA-21 in cancer cells is evaluated with favorable reliability and reproducibility and displays great potential and priority in complex biosensing and life assays.