Combining positive and negative signals can quickly and efficiently steer stem cells down complex developmental pathways to become specialized tissues that could be used in the clinic.

Researchers at the Stanford University School of Medicine have mapped out the sets of biological and chemical signals necessary to quickly and efficiently direct human embryonic stem cells to become pure populations of any of 12 cell types, including bone, heart muscle and cartilage.

The ability to make pure populations of these cells within days rather than the weeks or months previously required is a key step toward clinically useful regenerative medicine — potentially allowing researchers to generate new beating heart cells to repair damage after a heart attack or to create cartilage or bone to reinvigorate creaky joints or heal from trauma.

The study also highlights key, but short-lived, patterns of gene expression that occur during human embryo segmentation and confirms that human development appears to rely on processes that are evolutionarily conserved among many animals. These insights may also lead to a better understanding of how congenital defects occur.

At MIT they coaxed stem cells into making insulin:

http://npr.org/sections/health-shots/2014/10/09/354708628/scientists-coax-human-embryonic-stem-cells-into-making-insulin

https://reddit.com/r/biology/comments/2iw6dm/scientists_coax_human_embryonic_stem_cells_into/

At Harvard they coaxed stem cells to repair teeth:

http://www.seas.harvard.edu/news/2014/05/researchers-use-light-to-coax-stem-cells-to-repair-teeth

https://reddit.com/r/news/comments/26ype2/researchers_use_light_to_coax_stem_cells_to/