An Intelligent Fluorescence Sensing Platform Based on Entropy-Driven Toehold-Mediated Strand Displacement Cycle Reaction for Point-of-Care Testing of Mirna

Background MicroRNA (miRNA) has gradually become an emerging biomarker for early diagnosis and prognosis of various diseases due to its specific gene expression and high stability. With the development of molecular diagnosis and point-of-care testing (POCT) technology, developing simple, fast, sensitive, efficient, and low-cost miRNA sensors is of great significance for clinical applications and emergency rapid diagnosis. At present, entropy-driven toehold mediated chain displacement reaction, as a promising enzyme free isothermal amplification technique, is an important tool for ultra-sensitive biosensing applications. Results In this study, we used gold nanoparticles (AuNPs) as carriers and quenchers, modified them using self-assembled triple chain composite substrates AuNPs@A@B1/B2, and used dual reporter molecules for cascade cyclic amplification to amplify fluorescence signals, which proposed a fluorescent biosensor based on this reaction and build an intelligent fluorescence sensing platform for rapid detection of miRNA. We designed a highly specific self-programmable sensor using the acute ischemic stroke (AIS) biomarker miRNA-125a-5p as a sample, and achieved sensitive detection of miRNA in the range of 0.01 μM∼10 μ M under optimal conditions. It broke through the traditional detection limitations of weak signals and liberated the fluorescence detection environment. Significance In summary, this creative miRNA biosensor combined with POCT has demonstrated extraordinary detection potential, broad application prospects in the early diagnosis and prognosis monitoring of AIS, provides a novel miRNA universal detection strategy for the fields of biological and life sciences.