A new two-in-one microscope has helped scientists look inside cells
Researchers have combined two imaging techniques in a single microscope to produce high-resolution images of such cells.Researchers at the U.S. Department of Energy's Stanford Linear Accelerator Center (SLAC) National Accelerator Laboratory have combined two microscopic imaging techniques in a single microscope. This is how they obtained a high-resolution method for observing individual molecules in a cellular context.
They combined super-resolution fluorescence microscopy (SRM) and cryogenic electron tomography (cryo-ET). The former is great for tracking individual molecules, such as proteins, in a cell, but doesn't show scientists what's going on nearby. The second provides high-resolution images of cells, but can't pinpoint what individual molecules are "up to."
The researchers developed a device called a focused ion beam milling system with an attached scanning electron microscope, or FIB-SEM. The focused ion beam cuts away cellular material, leaving a very thin layer of frozen cell through which cryoET can penetrate. A scanning electron microscope then shoots electrons into the sample to produce high-resolution images.
Researchers are now developing different types of fluorescent tags - biosensors - to work under cryogenic conditions. Biosensors are fluorescent molecules that change their emission or excitation properties depending on the local environment, glowing one color in one environment and a different color in another.