Subcellular molecular imaging by means of MeV Secondary Ion Mass Spectrometry

The project’s main ambition is the development of a novel mass spectrometry imaging (MSI) method MeV-SIMS, which would open a window into sub-micron, sub-cellular imaging of heavy (>1kDa) molecules. Such powerful MSI tool would be in particular interest to biomedical sciences, where information about the distribution of elements and molecules in not yet completely available, despite its importance in understanding various processes within living tissue.

Within the project, we intend to develop a routinely available MSI analytical method, where ions within the MeV range domain would be generated in a sputtering ion source, accelerated in a tandem accelerator at the microanalytical center of Jožef Stefan Institute (JSI), and afterwards the continuous primary ion beam would be reduced to a very small intensity (approx. 5000 ions/s), allowing focusing to sizes between 500 nm and 1 µm. We plan on detecting the primary ions hitting the analyzed sample by efficiently monitoring secondary electrons and precisely measuring the Time-of-Flight of secondary ions.

We also intend to develop a novel sample preparation protocol, which would allow subcellular imaging of unaltered tissue cells, and to demonstrate the feasibility of such approach by analysis of plant tissue. In order to enhance the secondary ion yields of molecules with lower concentration, our aim is also to study several sample preparation protocols, which have proven useful in increasing the cationization of such molecules with keV primary ions.