Direct visualisation of heavy ion induced DNA fragmentation using atomic force microscopy.

Atomic Force Microscopy of phiX174 plasmids irradiated in vitro was used to visualise the DNA fragmentation induced by heavy ions and to compare it to the fragmentation pattern obtained after X-irradiation. Fragment distributions induced by low ion fuences were found to be much more shifted towards small fragment sizes than the distributions obtained after corresponding doses of X-rays. The average fragment length was found to be significantly smaller than the full plasmid length even for single ion traversals.