Specific and simultaneous detection of micro RNA 21 and let-7a by rolling circle amplification combined with lateral flow strip

Highlights: • Simultaneous detection of miRNA 21 and miRNA let-7a was realized based on rolling circle amplification coupled with LFS-RCA. • The designed padlock probes for miRNAs were specific, and were able to simultaneous amplification in a same sample solution. • Only one capturing probe was needed to bind with AuNps which was then able to be linked with two RCA products. • The strategy was fast, sensitive, and selective for miRNA let-7a and miRNA 21, with the LOD of 20 pM and 40 pM, respectively. -- Abstract: Owing to the pivotal function in post transcriptional gene modification, miRNA biomarkers are playing crucial role in tracking and diagnosing various forms of tumors in a short time period. Hence, the need to develop simple, sensitive and specific detection of miRNAs for precise diagnosis arises. This current study is aimed to develop a detecting platform by combining rolling circle amplification with AuNps-based lateral flow strip (LFS-RCA) for simultaneous detection of miRNA 21 and miRNA let-7a. The current methodology is simple, sensitive, specific and selective for miRNA let-7a and miRNA 21 with the limits of detection (LOD) as low as 20 pM and 40 pM, respectively. In this technique, rolling circle amplification is playing an essential role in increasing sensitivity and reducing experimental cost. Moreover, the padlock probe with high specificity can immediately identify the simultaneous amplification of multiple miRNAs targets, which may contribute in saving sample volume and detection time. Hopefully, in future with further development, this developed technique can be chosen as a potential tool for detection of miRNAs in clinical diagnosis.