Sensitive Colorimetric Detection of MicroRNA Based on Target Catalyzed Double-arm Hairpin DNA Assembling

The common drawbacks of the current colorimetric sensing platform using gold nanoparticles (AuNP) as an indictor is its relatively low sensitivity, which restrict their analytical application for low-level analytes, such as the detection of the microRNA (miRNA). In the present work, we developed a novel strategy to construct a colorimetric sensing platform for miRNA based on target catalyzed hairpin DNA assembling. Unlike a single-stranded DNA probe or a single-arm hairpin structure DNA probe, in our strategy the double-arm hairpin structure DNA probe was first designed, and was further demonstrated to work well in catalysis the of hairpin DNA assembly reaction, which significantly enhanced the sensitivity of the AuNP based colorimetric sensing platform. In addition, compared to other miRNA detection schemes reported previously, the proposed strategy is not only enzyme-free, label-free, immobilization-free, but also eliminates the need for any sophisticated instrumentation. The proposed strategy may open a new way to allow miRNAs expression to be profiled in a decentralized setting, such as at point-of-care.