DNA Tetrahedra Modules as Versatile Optical Sensing Platforms for Multiplexed Analysis of miRNAs, Endonucleases, and Aptamer-Ligand Complexes

The sensing modules for analyzing miRNAs or the endonucleases consist of tetrahedra functionalized with three different fluorophore-quencher pairs in spatially quenched configurations and hairpin units acting as recognition elements for the analytes. Three different miRNAs (miRNA-21, miRNA-221, and miRNA-155) or three different endonucleases (Nt.BbvCI, EcoRI, and HindIII) uncage the respective hairpins, leading to the switched-on fluorescence of the respective fluorophores and to the multiplex detection of the respective analytes. In addition, a tetrahedron module for the multiplexed analysis of aptamer ligand complexes (ligands = ATP, thrombin, VEGF) is introduced. The module includes edges modified with three spatially separated fluorophore-quencher pairs that were stretched by the respective aptamer strands to yield a switched-on fluorescent state. Formation of the respective aptamer ligands reconfigures the edges into fluorophore-quenched caged-hairpin structures that enable the multiplexed analysis of the aptamer-ligand complexes. The facile permeation of the tetrahedra structures into cells is used for the imaging of MCF-7 and HepG2 cancer cells and their discrimination from normal epithelial MCF-10A breast cells.