Fluorescence amplification based on DNA structural changes for enzyme-free detection of microRNA

For sensing biomarkers on site, this paper discusses detection of a microRNA (miRNA) by positional control of fluorescence molecules with DNA reactions. We designed a hybridization chain reaction-based system that can detect and amplify molecular signals as fluorescent signals without temperature control and enzymatic reactions. A target miRNA triggers to make a polymer structure by opening hairpin structure DNAs and this structural changes induce fluorescence enhancement. In experiments, we confirmed fluorescent amplification and linear relationship between the fluorescent intensity and the target concentration.

I. Introduction

Biomarkers for disease are important indexes for diagnosing and monitoring conditions of patients. Recently, microRNAs (miRNAs) have attracted attention as biomarkers for various diseases including cancers [1], [2], [4]–, periodontitis [3]. Moreover, miRNAs in salivas, serums, and bloods have been reported to have a high potential as biomarkers for diagnosing the grade and stage of diseases [5]. To utilize the indexes in clinical diagnosis and patient care, developing rapid, low-cost, and accurate measurement method is an important issue for point-of-care-testing of miRNAs.