A Silver Nanocluster-Based DNA Biosensor for Dual miRNA Biomarkers Detection in Breast Cancer

Early and accurate detection of multiple microRNAs is crucial for improving breast cancer diagnosis. In this study, we developed a label-free fluorescent biosensor using DNA-templated silver nanoclusters (AgNCs) for the simultaneous and separate detection of miR-21 and miR-195. By designing specific hairpin-shaped DNA probes, the biosensor can differentiate among four possible target combinations (no target, either miR-21 or miR-195 alone, or both present) based on the presence of targets. The emission was observed in the range of 350–355 nm. The biosensor exhibits high specificity and sensitivity, achieving detection limits of 2.75 nM for miR-21 and 8.75 nM for miR-195. These results underscore the capability of specific DNA structure with hosted AgNCs as a powerful fluorescent reporter for non-invasive multiplexed microRNA detection in early breast cancer diagnosis.