Super-resolution microscope offers revolutionary tool for exposing cell secrets
1:34 p.m., Sept. 11, 2012--The University of Delaware’s Bio-Imaging Center can now offer researchers a cool, new cutting-edge tool for peering into cells. It’s called a “super-resolution” microscope, and only a handful of universities have one.
The scientific journal Nature Methods declared super-resolution microscopy the Method of the Year in 2008 for its anticipated role in revolutionizing understanding of cellular biology.
Plastic in the ocean
The new Zeiss ELYRA PS.1 microscope, on lease from Carl Zeiss Inc., can see far beyond the wrinkly mitochondria that serve as the cell’s power plants and the Golgi apparatus, with its ribbony layers, that packages proteins. With this new scope, scientists can look at a single molecule.
“It’s an amazing tool,” says Jeffrey Caplan, the center’s associate director, as he showcases the instrument at the Delaware Biotechnology Institute. “You can look at pretty much anything in greater detail, in almost any scientific field, from yeast to platelets to nanomaterials.”
According to Caplan, the super-resolution microscope outshines the capabilities of conventional microscopes because it can break the diffraction limit of light.
Diffraction is the bending that occurs when light travels around an object or through a narrow opening in one. You can see diffraction in action if you hold the index and middle finger of one hand slightly apart and then move them closer together as you approach a bright light. You’ll eventually see dark parallel bands appear on your fingers from the distorted light waves.
Through a sophisticated, analytical process, the super-resolution microscope overcomes the diffraction barrier in two unique ways, according to Caplan. One way is by projecting a structured illumination or light pattern on the sample. After a stack of high-resolution images (on the order of 5 to 20 gigabytes in size) of a sample has been taken with the different light patterns, new high-frequency information can be extracted, doubling the resolution in all dimensions after it has been computationally restored.
The second way is by switching on a very small number of individual fluorescent molecules in an image at a time (so that they do not overlap) and then applying the Gaussian function in mathematics to precisely locate the position of each molecule. Single molecules spaced as close as 10-20 nanometers apart can be easily distinguished to produce an image with as much as a 20-fold improvement in resolution over traditional light microscopy. This process for each image is repeated some 20,000 to 80,000 times over 20 minutes to an hour as the many images are combined together to create one super-resolution image.
The high-tech tool is available for use by researchers at UD, as well as by academia, industry and government throughout the region, Caplan notes.
Donna Woulfe, assistant professor of biological sciences, and her laboratory group are among the UD researchers eager to use the instrument.
“We are using the new super-resolution microscope to conduct studies visualizing microparticles formed from blood platelets,” Woulfe says. “The super-resolution technology is especially useful for this since we are interested in identifying particular lipids exposed on the surface of the platelets and the microparticles, which can be specifically labeled with antibodies. These studies will help give us an idea of how the microparticles are formed from the platelets in a way that is just not possible using conventional light microscopes. This may be important, since some studies suggest that shedding of platelet microparticles takes place to a greater extent in patients with cardiovascular disease than in healthy patients.”
Kirk Czymmek, UD’s former Bio-Imaging Center director, who now leads a major microscopy facility for Carl Zeiss Inc., in New York, and Randall Duncan, chair of the Department of Biological Sciences, negotiated the lease arrangement with Zeiss to bring the super-resolution microscope to UD.
Caplan now wants to bring together interested UD researchers who have NIH RO1 grants to collaborate on a federal research proposal for funding the microscope to keep it permanently at the University. Potential collaborators and researchers interested in using the instrument may contact Caplan by email or call him at 302-831-3403.
The super-resolution microscope is another bright addition to the extensive imaging capabilities offered by UD. Last October, UD acquired a dual beam focused ion beam and scanning electron microscope (FIB-SEM), as the first major equipment acquisition for the Interdisciplinary Science and Engineering Laboratory, slated to open next year. The FIB-SIM microscope, which will facilitate research on a broad range of materials from polymers to semiconductors, is temporarily installed in Spencer Laboratory, where it is available to the UD community, as well as industry, government and academic partners.
Article by Tracey Bryant
Photo by Kathy F. Atkinson