A high-efficiency electrochemical biosensor based on AuNPs@Zr-MOF and enzyme-free cascade signal amplification for microRNA detection

Herein, a novel electrochemical biosensor on the basis of MB/AuNPs@Zr-MOF signal probe and enzyme-free cascade signal amplification was fabricated for the ultrasensitive detection of colorectal cancer (CRC)-associated miR-92a-3p. Impressively, compared with the traditional electrochemical probes, MB/AuNPs@Zr-MOF not only exhibits high loading for electroactive substances, but also shows enhanced electronic conductivity, thereby generating stable and high electrochemical signal. Meanwhile, under the assistance of the target-induced enzyme-free cascade signal amplification including multicomponent nuclease (MNAzyme) recycle catalytic and catalytic hairpin assembly (CHA), the sensitivity of proposed biosensor was further improved. Additionally, the DNA tetrahedral scaffold (TDNs) was served as an electrode support interface, which could greatly reduce the non-specific adsorption and improve the analytical performance. As a result, the developed biosensor enabled the miR-92a-3p with a detection limit as low as 0.36 fM. This work provided an efficient method to increase the sensitivity and the stability of electrochemical sensing platforms, showing great potential for the detection of biomarker and disease diagnosis.