SBF-SEM

Serial block face scanning electron microscopy (SBFSEM) creates three dimensional (3D) images of very small samples by repeatedly sectioning and scanning a block face with an electron beam. In SBFSEM, the sample is dried (biological samples must be fixed), stained with heavy metals, and embedded in a polymer to create the block face. The sample is then kept under vacuum in the SEM chamber and thin sectioned by a device called a microtome. Electrons are released from an emission source and focused into a beam that scans over the block face after each sectioning in a raster pattern. The collected electrons are processed into an image of the surface of each block face and the sections are reconstructed into a 3D image. SBFSEM is useful for imaging the smallest cellular networks that require high resolution such as neuronal circuits as well as imaging organelle orientation and composition in cells. (Credit: Brooke Anderson-White)