High Resolution Cryoelectron Microscopy
Measure | Cryoelectron Microscopy
The Leading Edge of Biological Imaging
At the MIT BioImaging Center, the next generation of cryoelectron microscopes are capable of imaging molecules and structures within cells. While a common use of electron microscopy in biological imaging is to view a thin section of a cell or tissue or to view the outline of molecules in a thin film of a heavy metal stain, we are more interested in determining the entire structure of a molecule or a cell. Through tomography and crystallography, we use high-resolution electron microscopy to see how molecules are arranged. In order to preserve the specimen and safeguard its molecular structure from the effects of electron beams, we freeze it to liquid nitrogen temperatures. Imaging at such extremely low temperatures is known as cryoelectron microscopy.
Composite views and powerful capabilities
To view the structure of a cell in three dimensions using high-resolution cryoelectron microscopy, we take a series of pictures at different angles by tilting the microscope grid after each shot, then put them together to create a composite. This technique also improves the signal-to-noise ratio, which tends to be poor since we have to image with as few electrons as possible to reduce radiation damage to the specimen's structure.
A critical feature of our electron microscope is an energy filter which enables us to image thick specimens. In addition, the microscope is housed in a specially designed room that protects it from stray electric and magnetic fields, fluctuations in temperature and humidity, and the random noise caused by vibrations. Because the microscope is under full digital control, it can be remotely controlled from an adjacent room and thus kept totally isolated. This design is an example of the BioImaging Center's commitment to applying the most advanced technologies available in our research. Based on our work to date, we hope to merge cellular tomography with light microscopy as well to better explore the cytoskeleton and adhesion structures, as well as the other protein machinery in a cell.
