Dual-Mode Sensing Platform Guided by Intramolecular Electrochemiluminescence of a Ruthenium Complex and Cationic N,N-Bis(2-(trimethylammonium iodide)propylene) Perylene-3,4,9,10-tetracarboxydiimide for Estradiol Assay

Herein, a dual-mode sensing platform using cationic N,N-bis(2-(trimethylammonium iodide)propylene)perylene-3,4,9,10-tetracarboxydiimide (PDA+)-assembled DNA strands as a quencher was suggested for estradiol (E2) detection. The aptamer chain was initially anchored with the Ru(II) novel molecule (Ru complex), which was recombined with carbohydrazide (CON4H6) and tris(4,4′-dicarboxylicacid-2,2′-bipyridyl)ruthenium(II) dichloride [Ru(dcbpy)32+] modified on copper oxide (CuO) nanospheres. Intramolecular electrochemiluminescence (ECL) occurring between CON4H6 and Ru(dcbpy)32+ effectively improved the reaction rate and increased the ECL efficiency. By employing effective van der Waals’ force, PDA+ was endowed with an efficient ECL quenching probe on an electrode. The signal on the ECL interface can be converted into quenching because of energy transfer between the intercalator and the emitter. Notably, cationic PDA+ possessing a large planar π–π skeleton improved advantageous activity of redox and DNA aptamer indurative loading capacity and directly generated a well-defined cathodic peak to execute the EC bio-detection. This method not only avoids the difficulty of assembling various signal indicators but also improves the sensitivity greatly using the quenching mechanism. In addition, disparate double-response signals coming from different principles of transduction are in a position to verify each other to improve the accuracy. Hence, examination areas of 0.001–100 nM with E2 for ECL and EC were obtained, supplying a novel sensing strategy with promising ideas and perspectives of detection platform construction.