New biomaterial gets “sticky” with stem cells
Just like the bones that support your body, your cells have their own scaffolding to hold them up. This scaffolding, known as the extracellular matrix or ECM, not just props up cells but also provides attachment sites, or “sticky spots”, to which cells can bind, just as bones hold muscles in place.
HFSP Young Investigator Grant holders Adam Engler and Guiseppe Battaglia and colleaguesauthored on Mon, 03 December 2012
A collaboration between researchers at the UC San Diego Jacob’s School led by Assistant Professor of Bioengineering, Adam Engler and The University of Sheffield Department of Biomedical Science, led by Professor Giuseppe Battaglia recently revealed that these sticky spots are found randomly throughout ECM in your body. However, the synthetic materials that scientists use to mimic ECM in the lab often do not contain such randomly distributed sticky spots and are more uniformly sticky for cells. The group mimicked this random stickiness in a foam biomaterial made out of diblock copolymers (figure 1) and found that this random stickiness was required for stem cells to properly adhere and likely for their development into mature tissue cells. In this sense, stem cells are like Goldilocks: the scaffold should not be too sticky or not sticky enough, it must be just right (figure 2) to maximize adhesion, and later, for maturation into tissue cells.
Figure 1: Foam figure
Drs. Engler and Battaglia explain “that the two diblock copolymers, one that is sticky and one that is not, will separate from each other in solution. Just like balsamic vinaigrette, we shook these two copolymers sufficiently to form randomly distributed nano-scopic patches of the sticky material – the balsamic vinegar – in a non-sticky material – the olive oil. Only this time we did it using a polymer foam as support, achieving patterning within a whole porous monolith.” At the appropriate ratios, this allows stem cells to respond by adhering to the foam as they would normally do in the body.
These data should help to better inform researchers of how to make their biomaterials appropriately sticky for stem cells to ‘feel’ their way around.
This work was supported by grants from the National Institutes of Health, Human Frontier Science Program, and the UK Engineering and Physical Sciences Research Council.
Cell instructive microporous scaffolds through interface engineering. Viswanathan P, Chirasatitsin S, Ngamkham K, Engler AJ, Battaglia G. J Am Chem Soc. 2012 Nov 19. [Epub ahead of print]