Damage to plasmid DNA induced by low energy carbon ions

Abstract

The damage induced in supercoiled plasmid DNA molecules by 1-6 keV carbon ions has been investigated as a function of ion exposure, energy and charge state. The production of short linear fragments through multiple double strand breaks has been demonstrated and exponential exposure responses for each of the topoisomers have been found. The cross section for the loss of supercoiling was calculated to be (2.2 +/- 0.5) x 10(-14) cm(2) for 2 keV C(+) ions. For singly charged carbon ions, increased damage was observed with increasing ion energy. In the case of 2 keV doubly charged ions, the damage was greater than for singly charged ions of the same energy. These observations demonstrate that ion induced damage is a function of both the kinetic and potential energies of the ion.

Ion‐Induced Fragmentation of Amino Acids: Effect of the Environment

“…[10,11] Since DNA carries the genetic information, most of the studies have been focused on its constituents. Films of plasmid DNA have been irradiated by low-energy electrons, [12] keV singly and multiply charged ions, [13,14] and more recently by swift ions. [15] At the molecular level, the fragmentation of nucleobases by low-energy electrons, [16,17] low-energy ions [18,19] and 100 keV protons [20,21] has been studied in the gas phase.…”

Very low-energy and low-fluence ion beam bombardment of naked plasmid DNA

“…A good way to study this issue is to use low-energy and low-fluence ions to directly bombard naked DNA in vitro to simulate the final-step interaction between the ions and DNA. There have been some investigations done on various low-energy radiations including low-energy ion bombardment of DNA [5][6][7][8][9][10]. The results showed that low-energy ions could produce plasmid DNA strand breaks.…”

Formation of gas phase macromolecular targets by laser desorption from surfaces

“…Secondary, singly ionised species can be formed through fragmentation events while multiply charged secondary ions are likely to be produced through Auger de-excitation following core ionisation by the primary particle [4]. Recently [5] we have investigated the interaction of singly and doubly charged, low energy, carbon ions with solid phase plasmid DNA and observed single, double and multiple double strand breaks. It was also observed that, for the same kinetic energy (2 keV), doubly charged ions induced more strand breaks than singly charged ions, indicating that the release of the potential energy of the ion was also important in the interaction.…”