Versatile and Ultrasensitive Electrochemiluminescence Biosensor for Biomarker Detection Based on Nonenzymatic...

Electrochemiluminescence (ECL), as a sensitive and controllable assay, offers a considerable opportunity for multiple types of biomarkers detection. However, constructing such a biosensor remains a significant challenge. Herein, an ultrasensitive and versatile ECL biosensor was constructed to detect multiple types of biomarkers from breast cancer by taking the strategies of nonenzymatic catalytic hairpin assembly (CHA) and hybridization chain reaction (HCR) amplification, as well as aptamer-triggered emitter release. Concretely, with the appearance of target 1 microRNA-21 (miRNA-21), abundant double-stranded DNA (dsDNA) polymers were generated on this biosensing surface via amplification circuits of CHA and HCR, which could be intercalated into substantial ([Ru(bpy)₂dppz]Cl₂) as ECL indicators to obtain an obvious enhancement of ECL signal for target 1 detection with a detection limit (0.1 fM). Furthermore, in the presence of target 2 human mucin 1 (MUC1) protein, the ECL signal had a distinct decrease, because aptamer recognition induced the release of [Ru(bpy)₂dppz]Cl₂ from the sensing surface, thus, achieving a sensitive detection for MUC1 with a detection limit (2.4 fg·mL^-1). Simultaneously, this sensing platform was applied to monitor the biomarkers from MDA-MB-231 breast cancer cells, suggesting that this method was applicable to detect real samples. Therefore, this platform is an applicable and versatile implement for the determination of multiple types of biomarkers to improve diagnostic accuracy and efficiency.