"Can we enrich the cell populations for cells that we want to use, whether they are totally undifferentiated cell types, partially differentiated, or completely differentiated?" Darling said. "It doesn't matter as long as it's targeted for the specific tissue application."
Darling's study, led by research assistants Rafael Gonzaelz-Cruz and Vera Fonseca, involved cloning adipose-derived adult human stem cells into 32 stem cell populations. They then poked, prodded, and measured the cells with an atomic force microscope, gaining measurements of how big they were, how sturdy they were under pressure, and how the force between them and the scope's cantilevered probe changed over time. The team found the cells exhibited a wide range of stiffness, viscosity and size.
Once they had the measurements, the researchers chemically induced the cells to differentiate and analyzed the levels of key metabolites produced by the cells as they matured a few weeks later. For each population, the metabolites indicated the relative proportion that differentiated into one tissue or another. Population 28, for example, apparently responded productively to chemical cues for producing cartilage, only somewhat well for producing bone and poorly to cues for making fat.
The key moment was when the researchers correlated each cell population's mechanical measurements with its metabolite data. Did the mechanical properties predict which populations would be the most successful in turning into bone cells or cartilage cells or fat cells? Sure enough, they did. The stiffest cell populations produced more bone. The squishiest cells were the ones that produced the most fat. The ones with the highest viscosity were the ones seemingly headed toward becoming cartilage.
Darling and his team then conducted a sorting simulation to dete
|Contact: David Orenstein |