Flow detection of UV radiation-induced DNA damage at a polypyrrole-modified electrode

A new electrochemical protocol for the detection of radiation-induced DNA damage, based on the coupling of a conducting-polymer detector and a flow injection system, is described. Changes in the interaction of DNA molecules with polypyrrole (PPy) films, after exposure to ultraviolet radiation, are exploited for generating the damage-sensitive current signals. Factors influencing the response of the flow detector, including the irradiation time or distance, are discussed. Injection rates of 30-60 per hour are obtainable in connection to 20 μL sample volumes and nanogram quantities of plasmid and chromosomal DNA. The new modified-electrode/flow-injection protocol offers great promise for detecting DNA damage in a faster and simpler manner compared to the common use of ordinary electrodes in batch systems. It also adds a new dimension of information based on the interfacial properties of damaged DNA at conducting-polymer/solution interfaces. The PPy-coated glassy-carbon electrode thus represents a useful addition to the arsenal of electrochemical tools for detecting DNA damage.