Sensing benzo[a]pyrene-DNA adducts formation via decrease of hybridization reaction

Toxicity of benzo[a]pyrene occurs because of the formation of covalent adducts with DNA guanines. In this work we report the attempt to detect this DNA-adduct using both an electrochemical assay based on gold nanoparticles and a surface plasmon resonance DNA sensor. Detection was achieved via inhibition of the hybridization reaction of oligonucleotide sequences after formation of the covalent adduct. Detecting oligonucleotide sequences have been designed to get high reactivity vs formation of the adduct and benzo[a]-pyrene 7,8-dihydrodiol 9,10-epoxide has been used to generate adducts. Formation of adducts in the nanomolar range was evaluated using the surface plasmon resonance sensor with both the oligonucleotide sequences containing guanines.