Integrated amplified aptasensor with in-situ precise preparation of copper nanoclusters for ultrasensitive electrochemical detection of microRNA 21

MicroRNA 21 (MIR21) has garnered much attention in recent years as an important disease biomarker. The detection of it in human system shows great significance for the healthy evaluation and major diseases early detection. Herein, a novel approach tactfully manipulates the in-situ precise preparation of copper nanoclusters on overlapping Y-shaped ds-DNA for MIR21 analysis were developed in the proposed integrated aptasensor. In the presence of target MIR21, overlapping Y-shaped ds-DNA was constructed on electrode. Copper nanoclusters were in-situ prepared on this effective template for target detection. Taking advantage of exonuclease T7 triggered targets recycling, hybridization chain reaction (HCR) and copper nanoclusters triple amplification strategy, linear detection of MIR21 was achieved from 10 pM to 0.1 fM with a detection limit down to 10 aM (S/N > 3). This approach provides a good model for integrating both synthesis and detection into one electrochemistry component. It showed promising potential for applications in aptamer related target detection in human serum analysis.