M4iM4i, The Maastricht MultiModal Molecular Imaging institute

The division Imaging Mass Spectrometry at M4I offers a unique infrastructure for state-of-the-art mass spectrometry based atomic and molecular imaging. Complementary imaging modalities allow the determination of the spatial distribution of biomolecules from cellular and tissue surfaces with spatial resolutions ranging from 50 nm to 200 µm. The range of desorption and ionization methods available allow the analysis of a variety of complex surfaces from single cells to larger histological tissue sections. Various “SpatialOMX” technologies are used to investigate the structure-function relation of biomolecules in their tissue environment using MS image guided laser capture microdissection.
High throughput tissue typing is achieved by several systems, including two Bruker Rapiflex MALDI Tissuetypers and a TIMS-TOF Flex system for ion mobility based structural imaging. A NanoTOF SIMS system equipped with a variety of ion guns is employed for high resolution molecular 3D imaging and depth profiling and tandem mass spectrometry for structural identification of small molecules such as drugs and metabolites. The institute utilizes 3 Xevo G2S systems as part of an intraoperative diagnostic system for precision medicine. High resolution, high throughput imaging proteomics is achieved with a MALDI enabled Orbitrap Elite and q-Exactive HF Orbitrap systems. New laser based post-ionization technologies have been implemented over the last years that boost molecular sensitivity 2 orders of magnitude. Additionally M4i has recently invested in an innovative system capable of imaging macromolecular assemblies that utilizes parallel detection capabilities of a Timepix3 detector. The infrastructure is equipped with several HPLC systems, as well as robots, image processing and analysis tools, including tissue classification and correlation software and protein data basing tools and a large scale data storage and cluster computing facility.
The core of the division Nanoscopy is a workflow for (Cryo-)electron tomography. The workflow starts on the CorrSight with live cell imaging of cell cultures on an EM carrier which can be used throughout the complete workflow in order to prevent loss of orientation and sample contamination or destruction. The CorrSight is a unique and dedicated light microscope for correlative microscopy including a fully integrated spinning disk system (Andromeda) with a patented optical design for 3D Live Cell imaging. Once a specific event or location has been identified by means of light microscopy and preserved by means of cryo-fixation, the vitrified sample can be re-examined on the CorrSight in a dedicated cryo-stage in order to precisely determine the position of interest. After transferring the sample to the Scios DualBeam, the identified region will thinned down to the appropriate thickness of about 200-300 nm without artifacts using the focused ion beam. The correlative MAPS software allows the transfer of all data from the CorrSight such as positions of interest and recorded images to the Scios DualBeam in order to know exactly where to prepare the lamella for subsequent high resolution cryo-TEM imaging. After thinning the samples to the proper thickness, the grids will be loaded in the autoloader on the Tecnai Arctica for high resolution cryo-tomography. The Tecnai Arctica is equipped with FEI’s high sensitive Falcon direct electron detector for low-dose imaging, FEI tomography software for automated low-dose tomography and EPU software for automated single particle data acquisition.
M4i is one of the flagship nodes of NEMI (Netherlands Electron Microscopy Infrastructure) for Multimodal molecular imaging. We are currently expanding our infrastructure with a combined EM-MS system which is included as part of the national infrastructure. This approach capitalizes on the mass spectrometry imaging strength of M4i and builds bridges between not only the EM and MS communities but also caters to research of the other national infrastructures such as X-Omics, proteins@work and the Netherlands Metabolomics platform.