Enzyme-free fluorescent biosensor for miRNA-21 detection based on MnO2 nanosheets and catalytic hairpin assembly amplification

MicroRNAs (miRNAs) have attracted enormous interest due to their involvement in complex regulatory functions and for being closely linked to some cancers. Thus, qualitative and quantitative detection of miRNAs has become an urgent necessity. In this study, we report an enzyme-free fluorescent biosensor for miRNA-21 detection based on MnO2 nanosheets and catalytic hairpin assembly amplification. Results showed that the detection limit for miRNA-21 was 0.33 nM (S/N = 3) and the linearity range was from 1 to 50 nM. Compared with traditional methods, such strategy is convenient, rapid, and low-cost and it can have a promising potential for miRNA detection in cancer.