Fig. 5

a A fluorescent detection of miRNA based on the in vitro synthesis of copper nanoparticles (CuNPs) by terminal transferase and ascorbate oxidation. The signal is enhanced by DSN-assisted target recycling. b A fluorescent detection of miRNA based on silicon or silver nanoparticles. The fluorescence of a single-stranded DNA probe is quenched by the nanoparticles, while fluorescence is recovered by target miRNA hybridization to the probe. c In this approach, the fluorescence of a single-stranded DNA probe is quenched by metal–organic frameworks (MOFs) or MoS₂ nanosheets, which is then recovered by miRNA target hybridization to the DNA probe. DSN duplex-specific nuclease