Introduction

Making Pathology Research More Efficient with Field Emission Scanning Electron Microscopy

A new, faster strategy uses scanning electron microscopy for ultrastructural imaging of large tissue sections.

Electron microscopy is an essential tool for pathologists, providing high resolution imaging of tissue structures, cells, organelles and microbes. However, ultrastructural analyses of large areas of tissue can be challenging and time consuming.

Dr. Mike Reichelt, a Principal Scientific Researcher at Genentech, Inc., USA, and his colleagues recently published an article describing an efficient workflow for imaging large tissue sections with backscattered electron – scanning electron microscopy (BSE-SEM) using ZEISS GeminiSEM for applications in ultrastructural pathology.

Dr. Mike Reichelt, Principal Scientific Researcher, Genentech, Inc., USA

We had a major need in our pathology department, namely, the analysis of healthy or diseased tissues at both the histological and ultrastructural level. I was able to develop a strategy focused on the preparation of large (several square millimeters) tissue sections with an emphasis on wide-scale image acquisition to easily correlate low magnification histologic overviews with highly resolved ultrastructural features within the same tissue section.

Dr. Mike Reichelt

Principal Scientific Researcher, Genentech, Inc., USA

Mouse kidney glomerulus in center surrounded by various renal tubules. Imaged with the ZEISS GeminiSEM scanning electron microscope.
Mouse kidney glomerulus in center surrounded by various renal tubules. Imaged with the ZEISS GeminiSEM scanning electron microscope.

Mouse kidney glomerulus in center surrounded by various renal tubules. Imaged with the ZEISS GeminiSEM scanning electron microscope.

Mouse kidney glomerulus in center surrounded by various renal tubules. Imaged with the ZEISS GeminiSEM scanning electron microscope.

Looking for a New Solution for Ultrastructural Analysis of Large Tissue Sections

Traditionally, analysis of tissues at the ultrastructural level has most often been performed with the transmission electron microscope (TEM). While this procedure has been used for decades with great success, it is time consuming and has many hurdles:

  • The small size of TEM grids limits the size of the tissue section.
  • Grid bars further limit and obscure the field of view.
  • The preparation of ultrathin sections requires special training and skilled personnel.
  • It can be extremely challenging and time consuming to correlate the high magnification TEM view with the ROIs defined by light microscopy.

 

Leveraging the Digital Zoom of the FE-SEM

Imaged with ZEISS GeminiSEM Field Emission Scanning Electron Microscope

Digital zooming from kidney tissue overview into glomerulus (glo). Right side: podocyte (pc) with foot processes (fp), basement membrane (bm) and capillary space (cs) with erythrocystes (ec). Imaged with ZEISS GeminiSEM.
Digital zooming from kidney tissue overview into glomerulus (glo). Right side: podocyte (pc) with foot processes (fp), basement membrane (bm) and capillary space (cs) with erythrocystes (ec). Imaged with ZEISS GeminiSEM.

Digital zooming from kidney tissue overview into glomerulus (glo). Right side: podocyte (pc) with foot processes (fp), basement membrane (bm) and capillary space (cs) with erythrocystes (ec). Imaged with ZEISS GeminiSEM.

Digital zooming from kidney tissue overview into glomerulus (glo). Right side: podocyte (pc) with foot processes (fp), basement membrane (bm) and capillary space (cs) with erythrocystes (ec). Imaged with ZEISS GeminiSEM.

The Advantage of FE-SEM for Pathology Analysis of Large Tissue Sections

In contrast, these hurdles are eliminated when imaging tissues with modern field emission scanning electron microscopes (FE-SEMs) in combination with sample processing strategies that allow the preparation of large intact tissue sections (several square milimeters). Their new workflow takes full advantage of the very large scan fields possible with modern FE-SEMs that allow for the acquisition of large overview images which can be explored at the ultrastructural level by digitally zooming into the images.

Since its implementation in our lab, this BSE-SEM-based multiscale imaging procedure has substantially simplified and accelerated our ultrastructural tissue analysis. Nearly 100% of all ultrastructural tissue imaging projects (at least 20 per year) are now run on ZEISS GeminiSEM.

 

Dr. Mike Reichelt

Principal Scientific Researcher, Genentech, Inc., USA


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