Programmable hairpin assembly circuit-cascaded DNAzyme amplification for ultrasensitive miRNA-146a detection via high-stable perovskite nanocomposite biosensor.

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.