Biomedical Engineering Reference
In-Depth Information
2.2.2. Cell-Scaffold Interactions
Much of the body is made up of extracellular matrix (ECM), which is a
network of fibrous proteins produced by fibroblasts and smooth muscle cells.
The ECM is not inert, as it has a significant effect on the cells growing on it. In
tissue engineering, researchers need to understand how the ECM affects the
cells, and also how growing the cells on a different material, such as a biode-
gradable polymer or a culture dish, will be different.
To examine the effects of ECM on cell behavior, different components of
the ECM can be isolated and cell growth experiments can be run while adding
the different components. Mooney et al. did this with hepatocytes and found that
these cells do not normally proliferate in a dish, but will if such ECM compo-
nents as laminin, fibronectin, and collagen are added (60). Similar work was
done by Gerlach et al. showing that hepatocyte function improved when grown
on collagen (22). Extracellular matrix can have effects other than aiding cell
proliferation: cells can also migrate over the ECM. Fibroblasts grown on three-
dimensional collagen matrices are observed to sprout dendrites and pull them-
selves along the fibers of the ECM (24) (Figure 13).
Figure 13
. Fiboblasts extend dendrites along fibers of extracellular matrix (23).
In addition to understanding a cell's response to contact with ECM, it is
important for tissue engineering purposes to examine cellular responses to other
materials, since there are many synthetic materials that can help in constructing
an organ. This sort of experiment is performed by growing the cells in contact
with the material in question, and the results can be interpreted visually or
chemically. The behavior of the cells varies widely depending on what material
and preparation methods are used (29).
