A universal ratiometric method for Micro-RNA detection based on the ratio of electrochemical/electrochemiluminescence signal, and toehold-mediated strand displacement amplification.

An ultra-selective and reproductive ratiometric platform was introduced based on the ratio of Ru(phen) electrochemiluminescence (ECL) signal and methylene blue (MB) electrochemistry (EC) signal, which was amplified using a specific and efficient toehold-mediated strand displacement (TMSD). The stable DNA nanoclews (NCs) were efficiently loaded with MB (MB-NCs) as EC signal tags after being synthesized utilizing a simple rolling circle amplification reaction. Besides, TiC-based nanocomposite could apply as a superb carrier for both Ru(phen) and gold nanoparticles (TiC-Au-Ru), resulting in a nearly constant ECL internal reference to eliminate the possible interferences.