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Electrogenerated chemiluminescence detection of adenosine based on triplex DNA biosensor

Ye, Sujuan, Li, Hongxia, Cao, Wei
Biosensors & bioelectronics 2011 v.26 no.5 pp. 2215-2220
DNA, adenosine, biosensors, chemiluminescence, detection limit, dissociation, electrodes, gold, oligonucleotides, ruthenium
A novel electrogenerated chemiluminescence (ECL) biosensor based on the construction of triplex DNA for the detection of adenosine was designed. The ECL biosensor employs an aptamer as a molecular recognition element, and quenches ECL of tris(2,2′-bipyridine) ruthenium (Ru(bpy)₃ ²⁺) by ferrocenemonocarboxylic acid (FcA). Through self-assembly technology, the ECL probe of thiolated hairpin adenosine aptamer tagged was self-assembled onto the surface of a gold electrode with an ECL signal producer Ru(bpy)₃ ²⁺ derivative (Ru-DNA-1). The adenosine aptamer, including a section of triplex characteristic chain, formatted triplex DNA with two other DNAs (DNA-2, Fc-DNA-3) in the presence of triplex DNA binder coralyne chloride (CORA). Fc-DNA-3 was tagged with an ECL quencher ferrocenemonocarboxylic acid (FcA), a quenching probe. In the presence of adenosine, the aptamer sequence (Ru-DNA-1) prefers to form the aptamer–adenosine complex with hairpin configuration and the switch of the DNA-1 occurs in conjunction with the generation of a strong ECL signal owing to the dissociation of a quenching probe. Meanwhile, a control experiment was performed; the ECL-duplex biosensor was designed to detect adenosine. The detection limits were 2.7×10⁻¹⁰molL⁻¹ and 2.3×10⁻⁹molL⁻¹ for the ECL-triplex DNA biosensor and ECL-duplex DNA biosensor, respectively, which demonstrated that the ECL-triplex DNA biosensor improved the sensitivity and specificity greatly.