DNA-Electrochemical Biosensors: AFM Surface Characterisation and Application to Detection of In Situ Oxidative Damage to DNA

In recent years increased attention has been focused on the ways in which drugs interact with DNA, with the goal of understanding the toxic as well as chemotherapeutic effects of many molecules. The development of fast and accurate methods of DNA damage detection is important, especially caused by anticancer drugs or hazard compounds. The DNA-electrochemical biosensor is a very good model for evaluation of nucleic acid damage, and electrochemical detection a particularly sensitive and selective method for the investigation of specific interactions. The electrochemical sensor for detecting DNA damage consists of a glassy carbon electrode with DNA immobilized on its surface. The starting materials or the redox reaction products can be pre-concentrated on the dsDNA-biosensor surface, enabling electrochemical probing of the presence of short-lived radical intermediates and of their damage to dsDNA. AFM images were used to characterize different procedures for immobilization of nanoscale DNA surface films on carbon electrodes before and after interaction with hazard compounds. The electrochemical transduction is dynamic in that the electrode is itself a tuneable charged reagent as well as a detector of all surface phenomena, which greatly enlarges the electrochemical biosensing capabilities.