A SUPERCOILED DNA-MODIFIED MERCURY ELECTRODE-BASED BIOSENSOR FOR THE DETECTION OF DNA STRAND CLEAVING AGENTS

DNA-damaging agents in the environment represent a serious danger to h uman health. We use a supercoiled DNA-modified mercury electrode as a fast-response biosensor for the detection of DNA strand cleaving agent s. The sensor is based on a strong difference between the a.c. voltamm etric responses of covalently closed circular (supercoiled) and of ope n circular (nicked) plasmid DNA. We show that the sensor can detect hy droxyl radicals in laboratory-prepared solutions and in various natura l and industrial water samples. The sensor is also capable of detectin g unknown DNA-damaging agents in industrial waters. (C) 1998 Elsevier Science B.V. All rights reserved.