DNA Damage Detection by Electrochemiluminescence Sensor of CdS Quantum Dots

Electrochemiluminescence assay integrates the advantages of electrochemical potential controllability and high sensitivity of luminescence analysis. The electrochemiluminescence sensor was fabricated to detect the DNA damage. CdS quantum dots were deposited on the surface of glass carbon electrode in 0.1 M CdCl2 and 0.02 M Na2S2O3 (0.1 M HCl, pH 2–3, 50 °C) by cyclic voltammetry, and then the amino-modified single strand DNA was immobilized on CdS modified electrode by the –CONH– bond using cysteine as linker agent. The electrochemiluminescence was used to study the interaction between perfluorooctane sulfonates and DNA, and H2O2 was used as the common reactant. The results demonstrated that the intensity of electrochemiluminescence signal increased with the increasing of perfluorooctane sulfonates concentration. Meanwhile, the electrochemical impedance spectroscopy indicated that the DNA charge transfer attenuated with the incubation of perfluorooctane sulfonates. These results reveal that perfluorooctane sulfonates can induce the distortion and change of DNA chain.