[Construction of microRNA-21 terahertz metamaterial sensing method based on duplex-specific nuclease triggered rolling circle amplification].

To construct of a terahertz metamaterial sensing method for detection of microRNA-21 (miRNA-21) based on duplex-specific nuclease triggered rolling circle amplification. First, a THz metamaterial sensing method was constructed, and verified by polyacrylamide gel electrophoresis and zeta potential; after optimizing the detection conditions of the sensor, different concentrations of miRNA-21 and other different miRNAs were detected. And this biosensor was compared with other miRNA detection methods; finally, the recovery rate of the biosensor was evaluated. Under the optimal experimental conditions, through the dual signal amplification strategy of duplex-specific nuclease (DSN) cycle recognition and rolling circle amplification (RCA), the THz metamaterial sensor has a response range of 10 fmol/L to 10 nmol/L to the target miRNA-21, with a detection limit of 8.49 fmol/L. And the biosensor has good specificity with the ability to recognize the target miRNA-21 from a variety of microRNAs. And the experiment with recovery rate from 94.33% to 115.33% has been further verified in commercial human serum samples. The terahertz biosensor can achieve highly sensitive and specific detection of the target miRNA-21, which proves the potential for label-free diagnosis and early warning of miRNA-related diseases.