Shielded loop-mediated catalytic hairpin assembly for the specific detection of microRNA

MicroRNAs (miRNAs) are highly promising biomarkers, especially in the diagnosis, prognosis and therapeutic monitoring of diseases such as cancer. The unique nanostructure of DNA makes it particularly useful in biosensing. Catalytic hairpin assembly (CHA) is a promising enzyme-free and efficient isothermal amplification method. However, its performance and application value are limited by background signals. This study presents shielded loop-mediated catalytic hairpin assembly (SL-CHA). Complementary nucleic acids were introduced into the hairpin loop to inhibit the activity of single-stranded bases, and CHA exhibited a lower background signal with the same signal amplification ability. SL-CHA showed better performance in miRNA-224-5p detection in serum, demonstrating its good potential for the clinical detection of miRNAs.