A unique, shape-shifting property—previously only identified in man-made materials—has been discovered to also exist in stem cells.
In a study published on Sunday in the journal Nature Materials, scientists at the University of Cambridge, UK, describe a strange event that occurred when observing the physical changes that occur as stem cells grow and mature into the various cell types in the body.
Most materials in nature, when stretched or squeezed, will then revert back to their original shape. But a select few materials will do the opposite: once stretched or squeezed they maintain their new shape. These so-called “auxetic materials,” which can act as a kind of super-absorbent sponge, are of great interest to materials scientists and engineers looking to improve methods to create everything from soundproofing to bulletproof vests.
In this study, the research team—made up of biologists, engineers and physicists—were completely shocked when they saw stem cells exhibiting distinct auxetic properties as they began to transform into tissue-specific cells. As the study’s lead author Kevin Chalut noted in a recent news release:
“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 surroundings. This property has not, to my knowledge, been seen before at the cellular level—and is highly unusual in the natural world.”
Chalut and his colleagues were able to spot this unique property by treating the fluid that surrounds the cell’s nucleus, called the cytoplasm, with a particular type of dye. As the cell transformed and matured into a tissue-specific cell, the nucleus absorbed the colored dye. This was an indication that the nucleus itself was expanding—perhaps in order to absorb key molecules residing in the cytoplasm that are required for a transformation.
This research stands to not only improve our understanding of stem cells’ underlying molecular biology, but also to inform the related fields of engineering and materials science. It is a strong reminder of the importance of basic research; that even as the field of regenerative medicine moves forward into the clinic, it is still vital for organizations such as CIRM to support and foster this type of research.
As CIRM-grantee Irv Weissman stated in a recent video on the importance of basic research:
"This happens over and over again in basic research. If you keep your mind open you will begin to see things."
A biophysicist by training, Chalut agrees, stating that that his team’s discovery is just another indication of how much we still have to learn about nature:
“Despite great technological effort, auxetic materials are still rare and there is much to discover about them…. [But] studying how auxecity evolved in nature will guide research into new ways to produce auxetic materials, which might have many diverse applications in our everyday life.”