Enzyme-free electrochemical biosensor based on bio-barcode amplification for ultra-sensitive detection of microRNA

The rapid and accurate detection of miRNAs is of great significance for early diagnosis and treatment of cancer. Hence, a novel enzyme-free and label-free electrochemical biosensor based on bio-barcode amplification for detecting miRNAs was presented. Sandwich structures constructed of magnetic nanoparticles modified with DNA probes, gold nanoparticles with numerous barcoded DNA strands that hybridized with target miRNAs were fabricated as the amplifier. The released barcoded DNA strands then acted as the secondary targets and triggered the electrochemical sensor with a significant electrochemical response. A highly sensitive (detection limit of 0.24 fM) and selective electrochemical miRNA detection was realized, which has great potential for application in miRNA-related clinical diagnosis and biochemical research. Graphical abstract A novel biosensor based on bio-barcode amplification for the electrochemical detection of miR-7a was successfully developed.