DNA conformation change or damage induced by low-energy ion irradiation has been of great interest
owing to research developments in ion beam biotechnology and ion beam application in biomedicine.
Mechanisms involved in the induction of DNA damage may account for effect from implanting ion charge.
In order to check this effect, we used both ion beam and neutralized beam at keV energy to bombard
naked DNA. Argon or nitrogen ion beam was generated and extracted from a radiofrequency (RF) ion
source and neutralized by microwave-driven plasma in the beam path. Plasmid DNA pGFP samples were
irradiated with the ion or neutralized beam in vacuum, followed by gel electrophoresis to observe
changes in the DNA conformations. It was revealed that the ion charge played a certain role in inducing
DNA conformation change. The subsequent DNA transfer into bacteria Escherichia coli (E. coli) for mutation
analysis indicated that the charged ion beam induced DNA change had high potential in mutation
induction while neutralized beam did not. The intrinsic reason was attributed to additional DNA deformation
and contortion caused by ion charge exchange effect so that the ion beam induced DNA damage
could hardly be completely repaired, whereas the neutralized beam induced DNA change could be more
easily recoverable owing to absence of the additional DNA deformation and contortion.