Speedy, Specific, Synchronous Sensing Platforms with Ruthenium Complexes for Multiplexed MicroRNA Detection.

Inspired by our previous study on Ru(II)-based compounds for the construction of a sensing platform toward detection of microRNA-185 (miR-185), we herein report new analytical platforms based on two additional Ru(II) compounds, Ru 2 and Ru 3, with larger aromatic ring structures and richer hydrogen bond donor/acceptor sites in comparison to the previously reported Ru 1, as simultaneous detection agents for miR-221/222, which work together to promote the occurrence and development of breast cancer. Molecular simulation docking was first used to predict the nucleic acid sequence binding affinity toward Ru(II) compounds to guide the experiment. The experimental results reveal that Ru 2 and Ru 3 can form a P-DNA@Ru sensing platform with the introduction of carboxyfluorescein (FAM)/5-carboxy-X-rhodamine (ROX) tagged single-chained probe DNA (P-DNA), to realize the discernment of the complementary P-DNA sequence of miR-221/222, giving the limit of detection (LOD) at the nanomolar level with a specific and speedy response. The detection mechanism was verified by binding capacity, luminescence decay, and fluorescence anisotropy (FA), as well as the polyacrylamide gel electrophoresis (PAGE) technique. Furthermore, the formed P-DNA@Ru 2/3 systems could be prepared for the simultaneous and synchronous detection of miR-221/222 sequences, improving the detection efficiency in a time-efficient manner and satisfying the speedy diagnosis requirements of current medical practive.