A Silly Putty ingredient could help advance stem cell therapy.
The "sponginess" of a human embryonic stem cell's environment can affect what type of specialized cells they eventually become, a University of Michigan news release reported.
A research team was able to generate working spinal cord cells by growing them one a soft "carpet" made up of a primary ingredient in Silly Putty.
This is the first study to "directly link physical, as opposed to chemical, signals to human embryonic stem cell differentiation," the news release reported. Differentiation is the process in which source cells morph into one of the body's many cell types.
This finding could help researchers more easily guide what stem cells "grow up" to be, allowing them to develop more-efficient therapies for conditions such as "amyotrophic lateral sclerosis (Lou Gehrig's disease), Huntington's or Alzheimer's," the news release reported.
The Silly Putty component, called polydimethylsiloxane, allows researchers to vary its post-height, which gives them control over the stiffness of the surface used to grow cells. The varying texture allows researchers to control the type of cells they create.
The team found cells that grew on "tall, softer micropost carpets" quickly became nerve cells, After 23 days the spinal cord cell colonies growing on the softer micropost carpets were four times more pure and 10 times larger than those grown on harder surfaces.
"This is extremely exciting," Jianping Fu, U-M assistant professor of mechanical engineering, said in the news release. "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. Our approach is a big step in that direction, by using synthetic microengineered surfaces to control mechanical environmental signals."
The researchers hope these types of therapies will one day help patients grow nerve cells.
"Professor Fu and colleagues have developed an innovative method of generating high-yield and high-purity motor neurons from stem cells," Eva Feldman, the Russell N. DeJong Professor of Neurology, said in the news release. "For ALS, discoveries like this provide tools for modeling disease in the laboratory and for developing cell-replacement therapies."
The cells grown on the soft micropost carpets showed electrical behavior similar to those found in human neurons. A signaling pathway was also identified.
"Our work suggests that physical signals in the cell environment are important in neural patterning, a process where nerve cells become specialized for their specific functions based on their physical location in the body," Fu said.