Evaluation of damage to DNA induced by UV-C radiation and chemical agents using electrochemical biosensor based on low molecular weight DNA and screen-printed carbon electrode

摘要

There is great interest and need to detect and evaluate damage to DNA by environmental factors. In the present paper, simple electrochemical DNA biosensors composed of commercially available screen-printed carbon electrode (SPCE) and low molecular weight double-stranded DNA (dsDNA) recognition layer are reported and applied to the detection of damage to DNA by UV-C radiation and reactive oxygen species produced by the Fenton type reaction in model as well as mineral water samples with additives. Complex DNA biosensor response is based on square-wave voltammetric intrinsic signal of the guanine moiety as well as that of the intercalative indicator thioridazine, cyclic voltammetric response of the [Fe(CN)_6]~(3-/4-) indicator in solution and on electrochemical impedance spectroscopy when the measurements can be performed in the same solution. For the last two types of measurements, the biosensor was also used with an interface between the SPCE and DNA formed by a composite of carboxylated single-walled carbon nanotubes and chitosan to enhance the transducer conductivity. Individual electrochemical/electrical signals depend on the time of biosensor incubation in a cleavage medium and their profiles characterize process of deep DNA degradation.