You have probably seen the active chemical ingredient polydimethylsiloxane before: It comes in a small egg-shaped container and is best known by its trademarked name — Silly Putty.

In addition to being in the Toy Hall of Fame, it now appears the silly polydimethylsiloxane putty may prove useful for growing stem cells.

A mechanical engineering lab at the University of Michigan has discovered that Silly Putty can be used as “scaffolding” in cell culture dishes. It provides a structure and medium for containing and promoting the division and growth of cells in the lab.

The new spinal cord cells sent electrical impulses just like real spinal cord cells in the human body.

But this science lab wasn’t just “toying” around.

Human embryonic stem cells can be harvested from all areas of the body, such as skin and fat cells. But cultivating them is the problem, and the scientists found that when they were are placed on an ultrafine carpet made of the main ingredient in Silly Putty — polydimethylsiloxane — in a petri dish, they grow more efficiently.

Even better, the stem cells grown on the Silly Putty carpet were more likely to become specialized cells such as human spinal cord cells — a process known as differentiation.

Differentiation is the crucial process and the reason why embryonic stem cells are the holy grail of regenerative medicine; but it is also the source of controversy.

The scientists, led by Jianping Fu, an assistant professor of mechanical engineering at University of Michigan, added microscopic posts in a specially-designed growth system for the stem cells. The posts contained polydimethylsiloxane and provided soft, plush scaffolding for the cells to rest and grow.

A novel yet practical method by which researchers can coax human embryonic stem cells to turn into any type of cell they want.

After 23 days in the culture dish, the colony of stem cells that grew on the soft scaffolding were four times more likely to regenerate into spinal cord cells than cells that grew on traditional plates that were more rigid.

The researchers also determined that the new spinal cord cells sent electrical impulses just like real spinal cord cells in the human body.

The findings provide a novel yet practical method by which researchers can coax human embryonic stem cells to turn into any type of cell they want, such as nerve cells, bone cells and tendon cells — in larger quantities than ever before.

The results also offer a hope for diseases that could benefit from the growth of new nerve cells. Fu and his collaborators are already distributing their technique to another lab at Michigan that studies Lou Gehrig’s disease, which kills motor neurons in the brain and spinal cord.

“This is extremely exciting,” Fu said in a statement. “To realize promising clinical applications of human embryonic stem cells, we need a better culture system that can reliably produce more target cells that function well.”

Apparently, the scientists were able to use Silly Putty to accomplish just that.

This study is published in the journal, Nature Materials.