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)3
2+] modified on copper
oxide (CuO) nanospheres. Intramolecular electrochemiluminescence (ECL)
occurring between CON4H6 and Ru(dcbpy)3
2+ 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.