Simple differentiation
20 Sep 2010 by Evoluted New Media
The scaffold on which stem cells differentiate plays a role determining which type of cell they become leading researchers to create a novel type of matrix to grow them on.
The scaffold on which stem cells differentiate plays a role determining which type of cell they become leading researchers to create a novel type of matrix to grow them on.
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Human mesenchymal stem cell growing on a plate of long microposts approximately 13 microns in length. This cell will differentiate into a fat cell Credit Jianping F |
Suspecting traction forces were involved in differentiation, Jianping Fu and colleagues at the University of Michigan examined slight forces exerted by stem cells on the matrices they were attached to. They found the stiffness of the material on which stem cells are cultivated in the lab helps to determine what type of cell they become.
“Our research confirms that mechanical factors are as important as the chemical factors regulating differentiation,” said Fu, an assistant professor in mechanical and biomedical engineering, “The mechanical aspects have, until now, been largely ignored by stem cell biologists.”
Fu says that stem cell differentiation could be predicted as early as day one when the process normally takes several weeks. He hopes the work could speed up the process and have applications in drug screening and regenerative medicine.
This discovery led researchers to develop a novel type of stem cell matrix whose stiffness can be adjusted without altering its chemical composition, something which can’t be done with conventional matrices. The new scaffold consists of lots of hair-like projections made of elastic polymer polydimethysiloxaine ¬– a key component of Silly Putty.
Researchers used human mesenchymal stem cells – found in bone marrow and fat tissue – and found they differentiated into bone when grown on stiffer scaffold and fat on more flexible ones. Using fluorescent microscopy, researchers were able to measure the bending of the microposts in order to quantify traction forces and predict how the cells would differentiate.
“Our study shows that if the stem cells determine to differentiate into one cell type then the traction forces can be much greater that the ones that do not differentiate, or differentiate into another cell type,” Fu said, “We prove that we can use the evolution of the traction force as early indicators for stem cell differentiation.”
The new matrix is manufactured through an inexpensive moulding process and is so cheap that researchers are giving it away to any interested scientists or engineers: “We think this toolset provides a newly accessible, practical method for the whole community,” Fu said.
