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Dual-Wavelength Electrochemiluminescence Ratiometry Based on Resonance Energy Transfer between Au Nanoparticles Functionalized g-C3N4 Nanosheet and Ru(bpy)32+ for microRNA Detection

Feng, Qiu-Mei, Shen, Yi-Zhong, Li, Mei-Xing, Zhang, Zhuo-Lei, Zhao, Wei, Xu, Jing-Juan, Chen, Hong-Yuan
Analytical chemistry 2016 v.88 no.1 pp. 937-944
DNA, absorption, carbon nitride, electrochemiluminescence, emissions, energy transfer, glassy carbon electrode, gold, hybridization, microRNA, nanogold, nanosheets, wavelengths
Here, a dual-wavelength ratiometric electrochemiluminescence (ECL) approach is reported based on resonance energy transfer (RET) from graphite-like carbon nitride nanosheet (g-C₃N₄ NS) to Ru(bpy)₃²⁺ for sensitive detection of microRNA (miRNA). In this approach, Au nanoparticles (Au NPs) functionalized g-C₃N₄ NS nanohybrid (Au-g-C₃N₄ NH) coated on glassy carbon electrode (GCE) could exhibit strong and stable ECL emissions with emission peak centered at 460 nm. The ECL emission at such wavelength matched well with the absorption peak of Ru(bpy)₃²⁺ as well as impeccably stimulating the emission of Ru(bpy)₃²⁺ at the wavelength of 620 nm, producing ECL-RET with high efficiency. Thus, based on the ECL signals quenching at 460 nm and increasing at 620 nm, a dual-wavelength ratiometric ECL-RET system was achieved. This system was then utilized for determination of target miRNA. With the attachment of thiol-modified molecular beacon on Au-g-C₃N₄ NH, target miRNA hybridized with the molecular beacon to form a DNA-RNA duplex. The obtained DNA-RNA duplex could be cleaved by duplex-specific nuclease to release target miRNA which would take part in the next cycle for further hybridization. Finally, the introducing of Ru(bpy)₃²⁺ was through the probe DNA-Ru(bpy)₃²⁺ complementary with the rest single-strand DNA on electrode. By measuring the ratio of ECL₄₆₀ ₙₘ/ECL₆₂₀ ₙₘ, we could accurately quantify the concentration of miRNA-21 in a wide range from 1.0 fM to 1.0 nM. This work provides an important reference for the study of dual-wavelength ECL ratiometry and also exhibits potential capability in the detection of nucleic acids.