MIT Researchers Develop Technique to Enlarge Brain Tissue Samples

Posted on January 19, 2015

Images of neurons in the hippocampus created with expansion microscopy

MIT researchers have developed a new technique that enables them to enlarge brain tissue samples. The technique allows researchers to nanoscale-resolution microscopy of large biological specimens. MIT is calling the new technique expansion microscopy. The above image showing neurons in the hippocampus was created using the new technique.

The new method works by blowing up the physically sample itself as opposed to trying to expand a given sample through magnification after being imaged with a microscope. The researchers found that they could expand a piece of tissue by embedding it in a swellable polymer material. A fluorescent dye is added to make the expanded sample easy to view. The scientists say the end result after the process is a swollen three-dimensional fluorescent cast of the original material.

Ed Boyden, associate professor of biological engineering and brain and cognitive sciences at MIT, says in a statement, "Instead of acquiring a new microscope to take images with nanoscale resolution, you can take the images on a regular microscope. You physically make the sample bigger, rather than trying to magnify the rays of light that are emitted by the sample."

The researchers say they were able to get resolution down to 70 nanometers using commercially available confocal microscopes with their enlarged samples. Fluorescent imaging with these types of microscopes is usually limited to a resolution of hundreds of nanometers.

The scientists explain expansion microscopy in this video. Take a look:



Photo: Fei Chen and Paul Tillberg/MIT