Highly Efficient Electrochemiluminescence Resonance\nEnergy Transfer System in\nOne Nanostructure: Its Application for Ultrasensitive Detection of\nMicroRNA in Cancer Cells

Abstract

The\nelectrochemiluminesce (ECL) efficiency of luminous emitter\ncan be enhanced by the means of electrochemiluminesce resonance energy\ntransfer (ECL-RET) with a matched donor. However, generally, the donor\nand acceptor pairs were separated in different independent nanostructures,\nexperiencing the challenging issues of limited energy transfer efficiency\nand luminous stability. Herein, we designed novel ECL-RET model within\none nanostructure containing the donor of tris­(4,4′-dicarboxylicacid-2,2′-bipyridyl)\nruthenium­(II) dichloride (Ru­(dcbpy)₃²⁺) and\nthe acceptor of CdSe@ZnS quantum dots (QDs) for acting as the ECL\nemitter (QDs-Ru­(dcbpy)₃²⁺), which significantly\nreduced the energy loss and improved the ECL efficiency of QDs because\nof the short path of energy transmission. To demonstrate the proof-of-concept,\nthe proposed QDs-Ru­(dcbpy)₃²⁺ was employed to\nconstruct a new kind of ECL biosensor that could achieve the ultrasensitive\ndetection of microRNA-141 (miRNA-141) combining target recycling amplification\nand the double-output conversion strategies. Notably, the proposed\ndouble-output conversion strategy enabled a small number of miRNA\nto be successfully transferred into a large number of reporter DNA\nwhich could capture numerous QDs-Ru­(dcbpy)₃²⁺-labeled signal probes on the sensing surface to realize the ECL\nresponse to the logarithm of the concentration of miRNA-141. With\nthe ultrahigh-efficient ECL-RET in one nanostructure and the dual\namplification including target recycling as well as double-output\nconversion strategies, the proposed biosensor realized ultrasensitive\ndetection of miRNA-141 and performed the concentration range from\n100 aM to 10 pM and the estimated detection limit was 33 aM (<i>S</i>/<i>N</i> = 3). Impressively, this method can\nsensitively detect the miRNA-141 of human prostate cancer cells and\nprovide a significant boost for the detection of other biomarkers\nin early cancer diagnosis and therapeutic monitoring.