<br/>Small noncoding microRNAs (miRNAs) have emerged as the ideal molecular biomarkers for early diagnosis of cancers, and understanding of the molecular pathogenesis. In this report, a label-free miRNA biosensor based on cross-shaped DNA origami nanostructure, coupled with methylene blue (MB) as hybridization redox indicator, was fabricated.<br/>The cross-shaped DNA nanostructures were used as substrates to support extended DNA capture probes on pre-selected locations. Therefore, the number and density of DNA probes can be well controlled, which, in turn, can enhance DNA probes’ reactivity, accessibility, and molecular recognition efficiency. The successful immobilization of DNA probes (ss-DNA) and its hybridization with targeted miRNA-21 molecules were confirmed by electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) methods. This strategy employed for determination of target miRNA-21 in cancer exhibited high sensitivity. Its linear detection range was from 0.1pm to 10nM with a lower detection limit of 78.3 fM. The selectivity of the miRNA biosensor was also studied by observing the discrimination ability of a non-complementary target. Overall, this strategy has demonstrated great potential for sensitive, selective and label-free determination of miRNA in cancer diagnosis at the early stage, and prognosis of certain diseases.

DNA nanostructure-based label-free detection of cancer miRNA-21 biomarker

2019 Spring National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.