Electrochemical DNA biosensor for the detection of interaction between di[azino-di(5,6-azafluorene)-κ2-NN′]dichlormanganous and DNA

A new Mn(II) complex of MnL2Cl2 (L = azino-di(5,6-azafluorene)-κ2-NN′) was synthesized and utilized as an electrochemical indicator for the determination of hepatitis B virus (HBV) based on its interaction with MnL2Cl2. The electrochemical behavior of interaction of MnL2Cl2 with salmon sperm DNA was investigated on glassy carbon electrode (GCE). In the presence of salmon sperm DNA, the peak current of [MnL2]2+ was decreased and the peak potential was shifted positively without appearance of new peaks. The binding ratio between [MnL2]2+ and salmon sperm DNA was calculated to be 2:1 and the binding constant was 3.72 × 108 mol2 L−2. The extent of hybridization was evaluated on the basis of the difference between signals of [MnL2]2+ with probe DNA before and after hybridization with complementary sequence. Control experiments performed with non-complementary and mismatch sequence demonstrated the good selectivity of the biosensor. With this approach, a sequence of the HBV could be quantified over the range from 1.76 × 10−8 to 1.07 × 10−6 mol L−1, with a linear correlation of r = 0.9904 and a detection limit of 6.80 × 10−9 mol L−1. Additionally, the binding mechanism was preliminarily discussed. The mode of interaction between MnL2Cl2 and DNA was found to be primary intercalation binding.