Researchers at the University of Cambridge in the United Kingdom have discovered a property in human stem cells that could be used to produce materials strong enough for soundproofing and even bulletproof vests. They are urging scientists to explore potential technology applications for the property known as “auxeticity”.
The Cambridge team, led by Dr. Kevin Chalut from the Wellcome Trust-Medical Research Council, Cambridge Stem Cell Institute, describes the property—related to elasticity—as “bizarre.” and says it has never before been seen at a cellular level. Until now, auxeticity has been demonstrated only in manmade materials and very rarely in nature—such as in some species of sponge.
The Cambridge team reports having observed auxeticity in the nuclei of embryonic stem cells—master cells within the body that can turn into any other type of cell.
“This is a pretty bizarre finding and very unexpected,” Chalut says. “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.”
Most materials when stretched will contract. If one pulls on an elastic band, the elastic itself will get thinner. The opposite is also true: squeeze a material and it will expand—for example, if one squeezes a tennis ball between both hands, the circumference around the ball gets larger.
However, material scientists have begun to explore auxeticity, an unusual property which has the opposite effect—squeeze it and it will contract, stretch it and it will expand. This means that auxetic materials act as excellent shock absorbers or sponges.
Findings of the study were released in a paper published in the journal Nature Materials.