Stimulated Emission Depletion (STED), an optical microscopy technique not limited by light diffraction, has become an indispensable tool for studying cellular function at a resolution unattainable with traditional optical methods. Yet, there has been a considerable limitation using STED to study dynamic interactions because one needs to use different colors to label the players, but until now STED has been monochromatic.
Researchers from Yale University with the help of New England Biolabs have developed a method of attaching specialty dyes to proteins that turn out to be compatible for doing dual color STED microscopy.
From an Optical Society announcement:
The key to their success was in overcoming the challenges in labeling target proteins in living cells with dyes optimal for two-color STED microscopy. By incorporating fusion proteins, the researchers were able to improve the targeting between the protein and the dye, effectively bridging the gap. This allowed the researchers to achieve resolutions of 78 nanometers and 82 nanometers for 22 sequential two-color scans of two proteins—epidermal growth factor and epidermal growth factor receptor—in living cells.
The researchers expect that using this and other novel approaches will expand live cell STED microscopy to three and more colors, enabling 3-D imaging.
Abstract in Biomedical Optics Express: Two-color STED microscopy in living cells