A smartphone-assisted electrochemiluminescent biosensor for highly sensitive detection of miRNA-21 based on Ru(bpy) 2 (L) 4+ @MOF-5.

A smartphone-assisted electrochemiluminescence (ECL) strategy based on Ru(bpy) 2 (L) 4+ as chromophores confined with metal - organic frameworks (Ru(bpy) 2 (L) 4+ @MOF-5) for the signal-amplified detection of miRNA-21 was developed. We synthesized a derivative of tris(2,2'-bipyridyl)ruthenium(II) complex (Ru(bpy) 2 (L) 4+ ) with high charges, which can be loaded into the MOF-5 by strong electrostatic interaction to prevent from leakage. In addition, nucleic acid cycle amplification was used to quench the signal of Ru(bpy) 2 (L) 4+ @MOF-5 by ferrocene. This method was applied to detect the concentration of miRNA-21 ranging from 1.0 × 10 -14 -1.0 × 10 -9 M with a low LOD of 7.2 fM. This work demonstrated the construction of a signal quenching strategy ECL biosensor for miRNA using Ru(bpy) 2 (L) 4+ @MOF-5 systems and its application in smartphone-assisted ECL detection.