Gold Nanoparticle-Assisted AFM Study of DNA Damage and Repair

The purpose of this research is to investigate gold nanoparticles as a potential scaffold for the characterization of DNA damage and repair using atomic force microscopy (AFM) techniques. The procedure consists of functionalizing the surface of gold nanoparticles with DNA which are then immobilized onto amine modified silicon or glass surfaces. Our objective is to examine various lesions in individual DNA molecules and follow in the AFM their direct reversal by DNA repair enzymes. In order to achieve this goal DNA repair proteins such as photolyase (repairs UV damaged thymine dimers in DNA using blue-light energy) is used as damage markers and imaged in complexes with DNA by AFM in order to locate and identify the damage sites. Force spectroscopy measurements will determine the mechanical fingerprints of various types of DNA damage caused by UV and gamma radiation and directly follow damage reversal in the presence of the repair activities. AFM images will be further compared with in vitro photoreactivation assay results.