Diaper compound to help scientists see tissues clearly

A modified form of the super-absorbent chemical used in disposable diapers can expand brain structures to four and a half times their original size, a recent study shows.

The process called expansion microscopy may enable scientists to take super-resolution pictures of healthy and diseased tissue throughout the body using common microscopes.

"For centuries, a scientist's ability to look at cells has been constrained by the power of the lenses they used to magnify them. We decided to try something different, and physically magnify the cells themselves," said Edward Boyden, associate professor at Massachusetts Institute of Technology, Cambridge.

Boyden linked brain cell proteins to a mesh of sodium polyacrylate and added water.

The polyacrylate mesh swelled and greatly expanded the size of protein complexes while preserving their normal structural arrangement in the cell.

This allowed the scientists to see previously hidden submicroscopic details of cell structures.

To demonstrate the technique's potential, the scientists took pictures of cell protein complexes before and after swelling.

They performed experiments on both rodent brain slices and cells grown in petri dishes.

Before treating with acrylate, scientists took pictures of certain parts of the cells with a high powered microscope designed to capture fine protein complex details.

Then they applied the acrylate, polymerised it to form a mesh, used enzymes to clear away unlinked proteins from the mesh and expanded the structures with water.

After expansion, they took pictures of the same locations using a lower powered microscope.

The overall three dimensional protein complexes within a certain brain cell circuit could be successfully enlarged.

"Our results show that we can scan large chunks of brain tissue with nanoscale precision. We think this can be applied to a variety of tissues and help answer a lot of different questions in science and medicine," Boyden concluded.

The study appeared in the journal Science.