Coupled electrochemiluminescent and resonance energy transfer determination of microRNA-141 using functionalized Mxene composite.

The electrochemiluminescence and resonance energy transfer (ECL-RET) method was adopted to detect miRNAs, in which the two-dimensional Ti₃C₂ Mxenes with high surface area modified with CdS:W nanocrystals (CdS:W NCs) were used as ECL signal emitter. Mxenes with a specific surface area of 5.2755 m²/g carried more emitters and promote ECL intensity. As an energy acceptor, BiOCl nanosheets (BiOCl NSs) have a wide UV–Vis absorption peak in the range 250 nm–700 nm, including the emission band of CdS:W NCs with 520 nm emission wavelength. Hence, BiOCl NSs are covalently bound to hairpin DNA 2 by amide bond to quench the ECL signal of CdS:W NCs. In the presence of miRNA-141, the hairpin DNA 1 modified on the GCE was unfold and then paired with hairpin DNA 2 to release miRNA-141 and quench the signal of the ECL biosensor. Then, the concentration signal of miRNA-141 was amplified by catalytic hairpin assembly. The novel specific biosensor demonstrated a satisfactory linear relationship with miRNA-141 in the range 0.6 pM to 4000 pM; the detection limit was as low as 0.26 pM (3 s/m) under the potential of 0 ~ -1.3 V and showed outstanding RSD of 1.19%. The findings of the present work with high accuracy and sensitivity will be of positive significance for the clinical diagnosis of miRNA in the future work. The construction process of the biosensor and electrochemiluminescence mechanism [ABSTRACT FROM AUTHOR]