Electrochemiluminescence aptasensor based on bipolar electrode for detection of adenosine in cancer cells

• An ECL approach on a wireless ITO bipolar electrode for adenosine detection in cancer cells was provided.
• Ferrocene as DNA tag was introduced on cathodic pole to enhance the ECL of Ru(bpy)32+/TPA system on anodic pole
• The ECL on the anodic pole could be decreased by the adenosine-induced removal of ferrocene-aptamer on the cathodic pole.
• The approach could detect adenosine in a wide range from 1.0 fM to 0.10 μM.

Here we report a novel approach for the detection of adenosine in cancer cells by electrochemiluminescence (ECL) on a wireless indium tin oxide bipolar electrode (BPE). In this approach, ferrocene (Fc) which is labeled on adenosine aptamer is enriched on one pole of the BPE by hybridization with its complementary DNA (ssDNA) and oxidized to Fc+ under an external voltage of 5.0 V at the two ends of BPE. Then, a reversed external voltage was added on the BPE, making Fc+ enriched pole as cathode. The presence of Fc+ promotes the oxidation reaction on the anodic pole of the BPE, resulting in a significant increase of ECL intensity using Ru(bpy)32+/tripropylamine (TPA) system as test solution. The presence of target adenosine was reflected by the ECL signal decrease on the anodic pole caused by the target-induced removal of ferrocene-aptamer on the cathodic pole. The decrease of ECL signal was logarithmically linear with the concentration of ATP in a wide range from 1.0 fM to 0.10 μM. This ECL biosensing system could accurately detect the level of adenosine released from cancer cells.