WP6: High Resolution MSI: WP6 will be led by Prof Heeren with the support of two incoming scientists and one outgoing ESR seconded to icoMetrix to perform data analysis. One of the incoming scientists will be from PERC to show correlation of MSI with the in vivo work. WP6.1 Ion mobility enabled molecular imaging Ion mobility (IM) spectrometry hyphenated with Imaging Mass spectrometry is an approach that has demonstrated the potential to provide direct insight in the shape, structure and position of biomolecules on tissue surfaces. The combination of mass spectrometry with ion mobility spectrometry has already proven an extremely successful technique for determining the structures of ions in the gas phase as it allows the separation of different structural isomers. The addition of a spatial imaging component allows the combined investigation of molecular and spatial structures. Tissue surfaces that tentatively contain misfolded and/or aggregated proteins will be investigated using the MALDI-Synapt instrument. On tissue digestion protocols will be applied for targeted aggregate degradation and protein identification. Gas phase ion mobility separation will be employed to distinguish different structural isomers of proteolytically cleaved peptides. Gas phase separation will also be utilized to separated nominally isobaric ions prior to dissociation. This will ensure the reduction of the complexity in the fragment spectra that has demonstrated to improve the quality of database identification. In a later stage the technologies developed in WP6.2 for top-down molecular imaging will also be evaluated in combination with ion mobility imaging mass spectrometry. WP6.2 High resolution molecular imaging in the ambient environment. In this sub-theme work package, novel ambient desorption and ionization techniques that allow the generation of multiply charged species in the ambient environment will be developed for spatial studies of tissue surfaces. The combination of local laser desorption (with and without a solid UV absorbing matrix) and charged particle jets will be developed to enhance the amount multiply charged species. LAESI, MALDESI and microDESI have all demonstrated to be functional to this extent. In this work package we will evaluated and further these technologies to move towards op-down imaging directly on diseased tissue in the ambient environment. As these technologies generate multiply charged species from tissue surfaces it becomes possible to employ top-down identification strategies based on the electron and photon based dissociation techniques described earlier in this proposal. In this research theme we intend to implement these technologies on Fourier-Transform Ion Cyclotron Resonance Mass Spectrometry. The data processing and interpretation strategies developed by AMOLF in collaboration with the US based Pacific Northwest National Laboratory will be employed to generate top-down protein images.