Dysregulation of
microRNAs (
miRNAs) is correlated with
cancer progression. In vitro detection methods using extracts from cell lysis cannot provide information about the spatial distribution of
miRNAs. Due to the development of
miRNA fluorescence in situ hybridization (FISH), increasing amounts of intracellular expression information are being obtained. However,
miRNA FISH suffers from weak signals and complex steps and thus remains very challenging. Herein, a strategy based on
DNA-templated
silver nanoclusters (AgNCs/DNAs) and their G-rich fluorescence enhancement effect was developed for FISH detection of
miRNAs in
gastric cancer cells. The method combines hybridization and signal amplification into one step, which allows imaging of intracellular
miRNAs immediately after hybridization. Most importantly, using the method based on our design, miR-101-3p, miR-16-5p and miR-19b-3p were found to be located in the nuclei of MGC803 cells with granulated shapes, indicating an unanticipated distribution pattern. In addition, before the final
miRNA FISH, we performed an optimization of AgNCs/DNAs and their G-rich fluorescence enhancement effect; we found that the effect occurred at shorter wavelengths emitting green fluorescence, with weakened red fluorescence at longer wavelengths. However, the components involved in the FISH process impacted the fluorescence properties so greatly that the probes finally exhibited slightly strengthened red fluorescence signals. Our method enables facile visualization of
miRNAs at the subcellular level, which may benefit the precise localization of
miRNAs in single cells in the future.