Jianping Fu, Ph.D., Assistant Professor, Mechanical Engineering, University of Michigan

Stem cells are rather immature cells that have the capability of giving rise to multiple mature cell types. For instance, mesenchymal stem cells can mature to become bone or fat. Interestingly, the surrounding environment is one cue that can tell the stem cell what to be. This is an image from an experiment that proves that point. Here, using bioengineering techniques, the investigators generated a silicone mold that displays many post-like structures. Then, they painted the tops of the posts with a material that cells can stick to and plated single mesenchymal cells on top of the mold. As seen in this picture, the cells were able to easily pull on and bend these long posts; they therefore interpreted this as a “soft” surface and they matured into fat cells. However, when the same material was used to make a mold with very short posts, stem cells placed on top of that mold were unable to bend the posts, since they were too short. These cells interpreted this as a “hard” surface and matured into bone cells. Scientists are now studying how cells interpret these “mechanical” cues from the environment that lead to different cell responses.