Scanning electron microscope with automated serial section and serial blackface imaging

• Subject Area: Neurosciences
• Term: Funded in 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 539190472

Techniques for visualizing the 3D ultrastructure of cells and tissues are becoming increasingly important in biology, medicine and environmental sciences. Volume electron microscopy combines serial and block face sectioning techniques with scanning electron microscopy (SEM) to image the sample volume three-dimensionally with high resolution. This allows, for example, the 3D representation of the interaction of nerve cells with tumors, the analysis of the connectivity of nerve cells in defined neuronal circuits or the examination of entire sensory organs in the skin when perceiving pain. This creates completely new insights into nanostructural functional relationships that were not achievable with previous methods. Volume EM technology is therefore a key technology for numerous innovative research projects at Heidelberg University. Electron microscopic imaging of tissues remains the method of choice to precisely record and understand both the internal cellular structure and the microenvironment of cells in the tissue context. For example, neuronal synapses and other contact points between cells, cellular connectivity or interactions in the neuropil can only be reliably identified using ultrastructure. To take the spatial complexity of the structures into account, tissues must be examined three-dimensionally. Over the last two decades, scanning electron microscopy (SEM) has established itself as a particularly powerful technique (three-dimensional electron microscopy (3DEM), volume electron microscopy). Two main techniques have been developed: Serial Blockface Scanning EM (SBEM) and serial sectioning on tapes or silicone wafers combined with automatic recording. Both techniques can be viewed as complementary, have different advantages and disadvantages and are now technically mature. Devices have recently become available for the first time that enable both SBEM and serial sectioning on wafers and their automatic recording. Furthermore, advances in sensor technology have been achieved so that high-quality recordings can be achieved with shorter recording times. These developments now allow higher throughput and thus make volume EM more practical to use. The device will be used for 3D representation of the ultrastructure of entire nerve cells and interaction of different cell types in different types of tissue (brain, peripheral nervous system, lungs, skin, tumors). This will give us new insights into the interactions between nerve cells and surrounding glial and tumor cells, enabling imaging of the tumor microenvironment. This will enable essential insights into fundamental structural and functional relationships of the nervous system as well as disease mechanisms in tumor biology.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Rasterelektronenmikroskop mit automatischer Serienschnitt- und Serial Blockface Bildgebung
• Instrumentation Group: 5120 Rasterelektronenmikroskope (REM)
• Applicant Institution: Ruprecht-Karls-Universität Heidelberg
• Leader: Professor Dr. Thomas Kuner