Interaction of low energy electrons with DNA: Applications to cancer radiation therapy

Presently, there exists considerable information on the mechanisms involved when low-energy electrons (LEEs) interact with biomolecules, including DNA. Since these electrons are produced in large quantities by ionizing radiation, knowing their mechanisms of action increases our understanding of radiobiological damage and modifications of this damage by morphological or chemical changes introduced in the DNA. In the present article, the results of experiments on LEE-induced damage to DNA modified by radiosensitizers, chemotherapeutic agents and gold nanoparticles are reviewed. DNA strand breaks and multiple lesions become more numerous with such modifications. They are usually due to an increase in the number and probability of forming transient anions of DNA constituents, and their decay into destructive channels, such as dissociative electron attachment. As shown in this review, by invoking the role of LEEs in the processes of radiosensitization, guidelines can be provided for the development of new radiosensitizers and improved protocols in the treatment of cancer patients with radiotherapy alone or in concomitance with chemotherapy.