Sensitive, Low-Background-Signal miRNA Analysis via the Self-Priming-Initiated Color Reaction Loaded on a Rolling Circle Amplification Product.

MicroRNAs (miRNAs) have been regarded as potential biomarkers in evaluating various diseases, such as pregnancy-induced hypertension and cancers. However, sensitive and reliable miRNA detection is still a challenge due to the low amplification efficiency and high background signal. Herein, we developed a colorimetric method for miRNA detection utilizing the self-priming-initiated color reaction loaded on a rolling circle amplification (RCA) product. In this method, a biotin-labeled RCA product is fixed on the surface of the streptavidin-coated wells, and the interfering components in samples are removed to avoid false reactions, thus reducing the background signals. Two signal amplification processes, including RCA and self-priming-initiated chain extension, endow the method with high sensitivity and a low limit of detection at the 10 fM level. In conclusion, our approach offers a promising perspective on sensitive and reliable miRNA detection and has the potential to be further utilized in biomedical research and early cancer detection.