Biomedical research at LIPSION - Present state and future developments

Since its commissioning in 1998 the high energy ion nanoprobe LIPSION has been developed into a versatile tool for a variety of applications in biomedical research. It includes quantitative trace element analysis with sub-micron spatial resolution and 3D-element imaging, as well as 2D- and 3D-microscopy of density distributions. The analytical methods base on particle induced X-ray emission spectrometry (PIXE) and PIXE-tomography. Rutherford backscattering spectrometry (RBS), as well as scanning transmission ion microscopy (STIM) and STIM-tomography. The continuous developments led to improved capabilities for trace element analysis. For sub-micron analysis the spatial resolution could be improved to 0.3 mu m for high resolution work and to 0.5 mu m for routine analysis. On the other hand, LIPSION was optimized for high sample throughput in quantitative element imaging maintaining a lateral resolution of 1-2 mu m. Recently the methods of PIXE- and STIM-tomography of biological specimens have been extended to limited angle tomography to avoid the complicated preparation of free-standing samples. Besides its analytical applications, the nanoprobe is also used for targeted irradiation of living cells with counted single ions for radiobiological research. It is capable of irradiating up to 20,000 cells per hour. Furthermore, we have developed a technique to achieve confined cell growth based on the proton beam writing technique (PBW) and agar. The paper presents an overview of the current biomedical research fields at LIPSION and gives an outlook on prospective developments. (C) 2011 Elsevier B.V. All rights reserved.