Stem Cell Nuclei Act Like Tiny Sponges

A unique property of stem cell nucleus makes them good candidates for use in sponges and bulletproof vests, according to University of Cambridge researchers.

The property called auxeticity is seen in materials that expand when stretched and shrink when squeezed. Until now, scientists could only manufacture materials with such properties such as sponges. There are a few biological materials that display the auxeticity property.

The current research shows that nature has already made tiny sponges within stem cells.

"This is a pretty bizarre finding and very unexpected. When the stem cell is in the process of transforming into a particular type of cell, its nucleus takes on an auxetic property, allowing it to 'sponge up' essential materials from its surrounding. This property has not, to my knowledge, been seen before at a cellular level and is highly unusual in the natural world," Dr Kevin Chalut from the Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute and lead author of the study.

Stem cells can differentiate into any kind of cell in the body. The auxetic property of the nucleus was seen only when the cell was transitioning from embryonic to a tissue cell.

For the study, researchers treated cytoplasm of stem cells with a colored dye. The team found that when the cells in transition stages were stretched, the nucleus soaked up the dye. The study showed that the nucleus had become porous.

In the future, biological materials might be used as sponges, shock absorbers and even bulletproof vests.

"There is clearly a lot we can learn from nature," adds Dr Chalut in a news release. "We are already seeing auxeticity explored for its super-absorption properties, but despite great technological effort, auxetic materials are still rare and there is still much to discover about them in order to manufacture them better. To overcome this, materials scientists can do what has become de rigueur in their discipline: they can learn from nature. Studying how auxeticity has evolved in nature will guide research into new ways to produce auxetic materials, which might have many diverse applications in our everyday life."

The study is published in the journal Nature Materials. Royal Society, the Wellcome Trust and the Medical Research Council funded the research.