A Laser Microbeam Implemented at the Heavy-Ion Microbeam Facility

The heavy-ion microbeam is used for targeted irradiation of living cells (in culture) with ions from the UNILAC linear accelerator of GSI [1]. A custom-made epifluorescence microscope is available for beam targeting as well as for observation of proteins (tagged by fluorescent dyes) in sub-compartments of interest. In order to gain better insight into DNA damage repair processes, we intend to employ a focused laser beam to locally bleach these fluorescent markers, thus unmarking sub-sets of molecules and analysing their dynamics and kinetics (FRAP, FLIM) [2]. Here, the development of a dedicated laser system for such bleaching experiments at the bio-endstation of the GSI microbeam facility is described.