The labs of the Electron Microscopy Facility are located in the CRTD and offer comprehensive services for embedding, sectioning and staining of a wide variety of biological specimens for ultrastructural analysis. In addition, the facility offers special services like high pressure freezing and freeze substitution, negative staining of particles, critical point drying and sputter coating of SEM samples, and immunolabeling procedures for correlative light and electron microscopy (CLEM), as well as access to sample preparation technology and transmission and scanning electron microscopes. More demanding projects including sample preparation, image acquisition, and data analysis are performed as scientific collaborations. In addition, the facilitiy constantly works on improvements of sample preparation protocols and on the development of new techniques, especially in the areas of CLEM, immunolabeling and cryopreparation for EM. The facility is part of the BioDIP network.

Services we offer:

Transmission Electron Microscopy (TEM)

• Conventional processing and embedding of cells and tissues into epoxy or methacrylate resins (Epon, Spurrs resin, Lowicryl)
• Microwave-assisted tissue processing and embedding
• Embedding into gelatin/sucrose followed by plunge freezing in liquid nitrogen for Tokuyasu cryo-sectioning
• High presssure freezing (HPF) and freeze substitution (FS)
• Ultramicrotomy at room temperature and at low temperature (Tokuyasu cryo-sectioning)
• Immunogold labeling of resin or Tokuyasu cryo-sections (postembedding labeling)
• Preembedding immunolabeling using HRP or Nanogold and silver enhancement
• Simultaneous immunofluorescence- and immunogold labeling for correlative light and electron microscopy (CLEM)
• Negative staining
• Imaging and data analysis
• Training and general support

Scanning Electron Microscopy (SEM)

• Conventional sample preparation for SEM (fixation, postfixation, dehydration)
• Critical point drying
• Sputter coating (with gold, gold-palladium, platinum, or chromium)
• Imaging and data analysis
• Training and general support

The facilitiy is equipped with state-of-the art instrumentation, like embedding automats, ultra-microtomes, cryostats, an automatic freeze substitution unit, a modular high vacuum coating system, critical point dryers and a sputter coater. Electron microscopy is performed with 2 TEMs, a table top SEM and a high resolution cold field emission SEM.

Sample preparation

• Tissue processing automats (Leica EM-TP, Leica EM-AMW)
• Automated freeze substitution unit (Leica AFS2) for progressive lowering of temperature (PLT) embedding and freeze substitution
• Knifemaker (Leica EM-KMR)
• 2 ultramicrotomes (Leica UC6), 1 equipped with a FC6 cryochamber for cryo-ultramicrotomy
• immunogold labeling automat (Leica IGL, e.g. for serial section analysis, ssTEM)
• Modular high vacuum coating device (Baltec, Med020, for carbon coating or glow discharging of EM-grids)
• Epifluorescence dissection microscope (Leica MZ6F, for target preparation)
• Critical point dryer (Baltec CPD 030, Leica CPD 300) for drying samples for SEM
• Sputter coater (Baltec SCD 050) for coating dry samples with conductive materials

Microscopes

• 100 kv Transmission Electron Microscope (FEI Morgagni 268D) with a SIS MegaView III camera
• 120 kV Transmission Electron Microscope (Jeol JEM 1400 Plus) with a Jeol Ruby camera and the Picture Overlay Program for Correlative Light Electron Microscopy (CLEM)
• Table top Scanning Electron Microscope (Hitachi TM 1000)
• Cold Field Emission Scanning Electron Microscope (Jeol JSM-7500F)
• Epifluorescence widefield microscope (Keyence BZ 8000)