Programmable hairpin assembly circuit-cascaded DNAzyme amplification for ultrasensitive miRNA-146a detection via...

The development of accurate and sensitive analytical methods for tumor-associated microRNAs (miRNAs) is of great practical significance for cancer monitoring. Herein, a novel fluorescent biosensor platform for miR-146a was constructed by combining a CsPbBr₃@MSN fluorescent probe with strand triggered hairpin assembly amplification (SHA)-driven catalysis-DNAzyme cascade amplification technology. The fluorescent probe was prepared by embedding the CsPbBr₃ quantum dots into mesoporous silica nanomaterials (MSN), which provided the stable and strong fluorescence properties, as well as good water solubility. In the presence of miR-146a, SHA was initiated, subsequently activating the DNAzyme to produce fluorescence. The amplification process in this assay was enzyme-free and only requires magnetic separation, thereby reducing the experimental cost. As a result, the detection limit of miR-146a reached 3.78 fM, with a linear range of 5 fM-50 nM. In addition, the developed fluoresence sensor demonstrated outstanding selectivity, reproducibility, stability, and recoveries (96.93-112%) in real sample analysis, making it promising for biological research and early disease diagnosis.