Study on the electrochemiluminescence behavior of ABEI and its application in DNA hybridization analysis

Abstract

The electrogenerated chemiluminescence (ECL) behavior of N-(4-aminobutyl)-N-ethylisoluminol (ABEI) was studied and it was found that ABEI could produce emission light when oxidized at a +1.0 V (vs. Ag/AgCl) potential in alkaline solution. The addition of H₂O₂ markedly improved the ECL sensitivity. The pH value of the solution as well as the H₂O₂ concentration and working potential all have influences on the ECL response. Under optimal conditions, ABEI can be detected in the range 1.3 × 10⁻⁶–6.5 × 10⁻¹² mol L⁻¹. A detection limit of 2.2 × 10⁻¹² mol L⁻¹ for ABEI was obtained at a signal-to-noise ratio of 3. ABEI was then used as a marker to label a known sequence oligonucleotide, which was used as a DNA probe for identifying a target ssDNA immobilized on a PPy modified electrode based on a specific hybridization reaction. The hybridization events were evaluated by the ECL measurements. The results showed that only a complementary sequence could form a double-stranded DNA with the DNA probe and give a strong ECL response. A three-base mismatch sequence and non-complementary sequence have no response. The intensity of the ECL was linearly related to the concentration of the complementary sequence in the range 9.6 × 10⁻¹¹–9.6 × 10⁻⁸ mol L⁻¹, the detection limit was 3.0 × 10⁻¹¹ mol L⁻¹.