The spaces, which varied in size at 25, 50, 100 and 200 micrometers across, were evenly singly and doubly crosslinked.
Human stem cells isolated from fat tissue were encapsulated in the singly and doubly crosslinked regions. The doubly-crosslinked spaces are comparatively cluttered with structures. The cells grew into clusters in the singly-crosslinked regions, but remained mostly isolated in the doubly crosslinked regions.
The larger the spaces in the checkerboard, the larger the clusters grew.
Cells were cultivated in media that promote differentiation into either bone or cartilage.
In both the singly and doubly crosslinked spaces, stem cells increasingly differentiated according to the media composition as the space size increased. The results were more dramatic in the singly-crosslinked spaces.
"Potentially, what's happening is the single-crosslinked regions allow better nutrient transport and provide more space for cells to interact and, because it's less restrictive, there's space for new cells and matrix production," Alsberg said. "Cluster formation, in turn, may influence proliferation and differentiation. Differences in mechanical properties between regions likely also regulate the cell behaviors."
The researchers are continuing to use micropatterning to understand the influences of biomaterials on stem cell fate decisions. This approach may permit local control over cell behavior and, ultimately, allow the engineering of complex tissues comprised of multiple cell types using a single stem cell source.
|Contact: Kevin Mayhood|
Case Western Reserve University