Zooming In

To improve the reach of optical microscopy, researchers are enlarging the biological features they wish to view.

Jan 20, 2015
Jef Akst

FLICKR, MILOSZ1By enlarging cells and tissues by up five times their normal size, MIT researchers were able to observe some of the smallest features of life—such as individual neurons and synapses—using traditional optical microscopes, according to a study published last week (January 15) in Science. Edward Boyden, codirector of the MIT Center for Neurobiological Engineering, and his colleagues used the new technique, called expansion microscopy, to view objects as small as 70 nanometers—well below the typical 200-nanometer limit of conventional optical microscopes.

“We hope we have a technology that will allow you to scan the nervous system of entire animals,” Boyden told The New York Times (NYT).

The technique hinges on a polymer that is commonly found in diapers. Absorbing up to 300 times its mass in water, the material has the potential to cause biological entities to swell. By fluorescently tagging the structures of interest, then infusing the tissue with the composite parts of the polymer and adding water, the researchers were able to force the tissue to expand uniformly in all directions—up to five times its original size—while maintaining its overall organization. Boyden hopes that more fine-tuning could eventually result in the ability to expand tissues by 10 times or more, he told NYT.