Ultrasensitive electrochemiluminescence biosensing platform for miRNA-21 and MUC1 detection based on dual catalytic hairpin assembly

Multi-target detection has been widely applied for the sensitive measurement of cancer-related biomarkers; however, the design and application of single platforms for diverse target detection are still challenging. Herein, a robust and sensitive electrochemiluminescence (ECL) biosensing platform was constructed for the measurement of microRNA-21 (miRNA-21) and mucin 1 (MUC1) based on dual catalytic hairpin assembly (DCHA). The catalytic hairpin assembly (CHA) process (Cycle I) was initiated by the target miRNA-21 to introduce abundant CdS:Mn quantum dots (CdS:Mn QDs) on the electrode surface, leading to a considerable ECL response and the sensitive detection of miRNA-21 with a limit of detection as low as 11 aM. Subsequently, the second CHA process (Cycle II) was triggered by the MUC1-aptamer complex, which allowed copious amounts of Au nanoparticles (AuNPs) to approach the CdS:Mn QDs. A decreased ECL signal was obtained due to the ECL resonance energy transfer (ECL-RET) effect between the CdS:Mn QDs and AuNPs; meanwhile, MUC1 was sensitively detected with a limit of detection of 0.40 fg mL−1. This single sensing platform achieved dual cancer-related biomarker detection, which could provide a rational approach for future clinical analyse.