Expanding the brain achieves super-resolution with ordinary microscopes

Engineers at the MIT-based Center for Brains, Minds and Machines have developed a way to make a brain expand to about four and a half times its usual size, allowing nanoscale structures to appear sharp with an ordinary confocal microscope.
The new “expansion microscopy” technique uses an expandable polymer and water to  enable researchers to achieve “super-resolution” to resolve details down to about 70 nanometers laterally, compared to about 300 nanometers (violet light), the previous limit with a diffraction-limited conventional microscope, and without the slower performance of existing “super-resolution” microscopes.
The MIT engineers who developed the technique, Fei Chen, Paul Tillberg and Edward Boyden, assert it offers the ability to use conventional microscopes to image large, intact, 3D brain structures with nanoscale precision for the first time.
“Expansion microscopy may provide a key tool for comprehensive, precise, circuit-wide, brain mapping,” Boyden said. The team has demonstrated the process on mouse, fruit fly, and zebrafish brains and is working with another team to apply it to human tissue.