Electrochemiluminescent bioassay based on Ru@Zr-BTC-MOFs nanoparticles for determination of let-7a miRNA using the hybridization chain reaction

Carboxyl-rich tris(4,4′-dicarboxylic acid-2,2′-bipyridyl) ruthenium(II) ([Ru(dcbpy) 3 ] 2+ ) and 1,3,5-phenyl tricarboxylic acid (H 3 BTC) were used as the organic ligand to synthesize the metal−organic frameworks by a simple one-pot hydrothermal method with ZrCl 4 as metal ion source. Subsequently, the excellent electrochemiluminescence (ECL) luminophore (denoted as Ru@Zr-BTC-MOFs) was obtained. The Ru@Zr-BTC-MOFs displayed outstanding ECL properties, and a sensitive ECL bioassay based on Ru@Zr-BTC-MOFs was designed for the detection of let-7a microRNA (miRNA) using hybrid chain reaction (HCR). Under the optimal experimental conditions, the proposed bioassay exhibited a good linear relationship in the range from 50.0 fM to 5.00 × 10 2 pM with a detection limit of 3.71 fM. Besides, the proposed sensor exhibited satisfactory performance in real samples. The recovery was 91 ~ 108%, and the relative standard deviation was less than 5.6%. It might have potential clinical applications for detecting miRNA in biomedical research and clinical diagnosis. Graphical Abstract The schematic diagram of the preparation of Ru@Zr-BTC-MOFs ( a ) and ECL sensor for detecting let -7a ( b ).