Method to deliver molecules within embryonic stem cells improves diffe...( Embryonic stem cell therapies have b...)

Embryonic stem cell therapies have been proposed for regenerative medicine and tissue replacement after injury or disease. However, the inability of stem cells to efficiently develop into the desired specific cell type such as muscle, skin, blood vessels, bone or neurons now limits the potential clinical utility of this therapy.

New research shows that delivering molecules within aggregates of embryonic stem cells via biodegradable microspheres enhances the efficiency and purity of differentiation, which is the process the cells undergo to become more specialized. Details of the microsphere-mediated delivery method, which is funded by the National Science Foundation, were presented on April 9 at the 235th American Chemical Society national meeting.

Directing embryonic stem cells to efficiently differentiate into a specific cell type has been challenging to this point, said Todd McDevitt, an assistant professor in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University. In my lab, were trying to better define and then control the environmental cues that regulate the fate and function of the stem cells.

Because physical interactions between stem cells is critical during normal embryonic development, most laboratory growth methods allow the cells to aggregate in three-dimensional clumps called embryoid bodies in order to differentiate. After individual cells aggregate together, hollow internal structures begin to develop and the aggregate becomes larger and more complex over time.

Many researchers add soluble factors to the culture dish medium to direct differentiation, but this does not accurately mimic the time and location of signaling events present in normal development, and may contribute to heterogeneous differentiation, said McDevitt. Our method focuses on incorporating the differentiation factors directly into the cell aggregates in order to have a more controlled me
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