The technology that makes disposable diapers so absorbent -- for which parents are so grateful -- has moved into research labs to help scientists see tiny details as they peer into their microscopes.
Researchers at MIT, looking for ways to get ever-higher resolution images out of their lab microscopes, turned to a material similar to that pampering baby bottoms -- not to make their microscopes more powerful, but rather to make the specimens they're examining grow bigger.
They were inspired by a substance known as sodium polyacrylate, which swells in size as it absorbs liquid in diapers.
Using a chemical cousin of the diaper ingredient, they painted key details of a biological sample with fluorescent dye, they soaked it in their special version of the diaper chemical.
As it expanded, it carried the dye along with it, and although the original molecules were destroyed, what was left was a detailed replica of the sample in dye -- only five times as large as the original.
Key details of the original molecule were preserved in the dye replica, the researchers report in the journal Science.
The technique may give many more scientists access to super-resolution imaging using just commercially available chemicals and inexpensive microscopes normally found in research labs, the researchers say.
"Instead of acquiring a new microscope to take images with nanoscale resolution, you can take the images on a regular microscope," says MIT researcher Ed Boyden. "You physically make the sample bigger, rather than trying to magnify the rays of light that are emitted by the sample."
Most microscopes have a fundamental resolution limit called the diffraction limit, which makes it impossible to visualize any objects much smaller than the wavelength of light used to view them.
For example, in a sample being viewed under blue-green light that has a wavelength of 500 nanometers, nothing smaller than around 250 nanometers can be seen.
"Unfortunately, in biology that's right where things get interesting," says Boyden, pointing out that protein complexes, molecules that move payloads into and out of individual cells, and many other cellular processes are all happening at the nanoscale.
Once commercially available microscopes usually limited to hundreds of nanometers, the new technique yielded a resolution down to 70 nanometers, the researchers say.
Other experts were quick to laud the new technique and the MIT researchers behind it.
"The idea to physically magnify biological specimens prior to imaging is simply brilliant. This is a very good and by no means obvious idea," says Ernst H. K. Stelzer, a microscopy expert at Goethe University in Germany.
