Learn about the development of expansion microscopy—a new technique for looking at biological specimens at the nanoscale—in this video from NOVA Digital. Paul Tillberg and Fei Chen, graduate students in Edward Boyden’s lab at MIT, developed a way to image the brain in fine detail using sodium polyacrylate (an absorbent material commonly found in diapers). The process involves embedding a dyed slice of a biological specimen, such as a brain, in the material. The specimen is destroyed; however, a cast is left in the material that can then be expanded with water. Because the material and cast are enlarged, regular light microscopes are able to see complex, three-dimensional nanostructures.
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