Novel Luminescent Nanostructured Coordination Polymer: Facile Fabrication and Application in Electrochemiluminescence Biosensor for microRNA-141 Detection

A series of novel luminescent nanostructured coordination polymers (Ce–Ru–NCPs) with tunable morphologies have been successfully synthesized on a large scale at room temperature by a facile and rapid solution-phase method using Ce3+ and tris(4,4′-dicarboxylicacid-2,2′-bipyridyl) ruthenium(II) dichloride (Ru(dcbpy)32+). Among them, the flowerlike Ce–Ru–NCP shows good cathodic electrochemiluminescence (ECL) characteristics. The ECL efficiency of the Ce–Ru–NCP/S2O82– system is about 2.34 times that of the classic tris(2,2′-bipyridyl) ruthenium(II) dichloride/S2O82– (Ru(bpy)32+/S2O82–) system. Hence, we report a sensitive ECL biosensor for microRNA-141 (miRNA-141) detection based on the flowerlike Ce–Ru–NCP as a cathodic ECL luminophore and a bipedal three-dimensional (3D) DNA walking machine as a signal amplifier. Through the bipedal 3D DNA walking machine, trace targets can be converted to substantial secondary targets (marked with the quencher dopamine), and a significant quenching effect on the ECL signal is achieved. As a result, the proposed biosensor exhibits a relatively good sensitivity for miRNA-141 detection and shows a dynamic range from 1.0 × 10–16 to 1.0 × 10–6 mol·L–1 with a limit of detection (LOD) of 33 amol·L–1 (S/N = 3). The Ce–Ru–NCP with tunable morphologies and high ECL efficiency, intensity, and stability possesses potential applications in ECL analysis.