ELECTROCHEMICAL BIOSENSORS FOR DNA HYBRIDIZATION AND DNA-DAMAGE

Recent trends in the development of DNA biosensors for nucleotide sequ ence-specific DNA hybridization and for the detection of the DNA damag e are briefly reviewed. Changes in the redox signals of base residues in DNA immobilized at the surface of carbon or mercury electrodes can be used as a sign of the damage of DNA bases. Some compounds interacti ng with DNA can produce their own redox signals on binding to DNA. Cov alently closed circular (usually supercoiled) DNA attached to the elec trode surface can be used for a sensitive detection of a single break of the DNA sugar-phosphate backbone and for detection of agents cleavi ng the DNA backbone such as hydroxyl radicals, ionizing radiation, nuc leases, etc. Using the peptide nucleic acid in the biosensor recogniti on layer greatly increased the specificity of the DNA hybridization bi osensor making it possible to detect point mutations (single-base mism atches) in DNA. (C) 1998 Elsevier Science S.A. All rights reserved.