Electrochemiluminescence Cascade Amplification Platform for Detection of Dual-microRNA and Operation of Concatenated Logic Circuit

The detection of multiple biomarkers is of great significance to the accurate diagnosis of diseases. Herein, in this work, we constructed an electrochemiluminescence (ECL) cascade amplification platform for dual acute myocardial infarction (AMI)-related microRNA detection. The Zn²⁺-dependent DNAzyme digestion reaction initiated by miR-133a and the duplex-specific nuclease (DSN) cleavage circuit initiated by miR-499 were carried out independently to form a fuel hairpin DNA and active initiator strand, respectively, to trigger a hybridization chain reaction, which constituted a two-input-regulated "AND" logic circuit based on single ECL signal output. The use of single signal probe (Ru(bpy)₃²⁺) avoided the time-consuming and costly process of multiple signal molecule labeling or modification. The independent operation of the DNAzyme digestion reaction and DSN-assisted target recycling improved the detection efficiency of the system. In addition, the detection of each miRNA had undergone a cascade amplification process, which improved the detection sensitivity for each target. Furthermore, benefitting from the strong complexation of EDTA with Zn²⁺ and the flexible design of DNA sequences, the two-input "AND" logic gate was extended to a four-input "INHIBIT-AND-INHIBIT" concatenated logic circuit, which broadens the application of the ECL method in logic gates. We anticipate that this cascading amplification strategy can be widely applied in accurate diagnosis of AMI and the construction of ECL-based logic devices.