Label-free miRNA fluorescent biosensor based on duplex-specific nucleases and silver nanoclusters

Abstract

MicroRNAs (miRNAs) are considered reliable biomarkers for a variety of diseases. However, its low abundance in organisms and high sequence similarity of homologous miRNAs make its accurate detection challenging. Here, we constructed a novel fluorescence biosensor for the detection of miRNA-155, a potential biomarker of neuroinflammation, based on duplex-specific nuclease (DSN) assisted amplification and DNA-templated silver nanoclusters (DNA-AgNCs) as a fluorescence signal probes. DSN-assisted amplification can transform unstable miRNA into stable DNA and amplify the miRNA signal at the same time. Using DNA-AgNCs as fluorescent signal probes for biosensors can avoid complex labeling processes and reduce costs. The biosensor shows excellent selectivity, reproducibility, wide linear range (1-600 nM) with detection limit of 0.86 nM, and potentiality for real sample detection. This work provided a potential universal biosensing platform for miRNA detection.