Simultaneous fluorescent detection of multiplexed miRNA of liver cancer based on DNA tetrahedron nanotags

The level of miRNA-21, miRNA-122, and miRNA-223 are always elevated when liver cancer is present at an early stage. In this paper, a novel assay to simultaneous detect miRNA-21, miRNA-122, and miRNA-223 was proposed based on DNA tetrahedron nanotags and fluorescence resonance energy transfer (FRET), which used a single laser stimulate wavelengh from one nucleic acid stain TOTO-1 to three diverse organic dyes (Cy3, Cy3.5, Cy5). In brief, a DNA tetrahedral nanostructure (DTN) was designed with three adaptor oligos on its vertices. TOTO-1, as a fluorescent donor, can imbed into native nucleic acid backbone of DTN. Three organic dye-functionalized strands (FRET oligos) are fluorescent receptors. In the presence of target miRNAs, they can be hybridized with FRET oligos and adaptor oligos on the vertices of DTN and the stable DNA tetrahedron nanotags are formed. As a result, the confinement of TOTO-1 is in close proximity to three fluorescence dyes, the FRET between TOTO-1 and three fluorescence dyes is generate efficiently in DNA tetrahedron nanotags. Point-of-care clinical applicability is demonstrated by sensitive multiplexed quantification of three miRNAs in 10% human serum samples.