Nappies to Neurons

The polymer granules inside babies’ nappies are exceptionally absorbent, capable of holding up to 300 times their own weight in water (or pee). But, scientists have come up with a wholly different purpose for this remarkable swelling material: expanding tissue samples for microscopy. This ingenious concept – which involves fluorescently labelling the tissue, incorporating the polymer, chopping up the cell structures (so they don’t resist expansion) and then adding water – increases a sample’s size equally in all directions by up to five times. Shown is an expanded sample of mouse brain containing neurons (green) and synapses (red and blue). Importantly, the technique allows researchers to see greater detail than would normally be possible with a regular light microscope. Other methods to achieve such 'super-resolution' images exist, but they require specialised, expensive equipment. With the new tissue-swelling technique, on the other hand, it might cost the price of a box of Pampers.

Written by Ruth Williams

Ruth Williams

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Ruth is a freelance science journalist based in the US. She's a regular correspondent for The Scientist, and her work has appeared in The Lancet, Nature, Scientific American Mind, BBC Focus and elsewhere. Twitter @rooph

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• Image by Fei Chen, Paul Tillberg and Edward Boyden
• Massachusetts Institute of Technology, USA
• Reprinted with permission from AAAS
• Research published in Science, January 2015