Any time an organ is engineered, have it be skin, a heart, or a pair of lungs; the way it is made is not by laying down mature differentiated cells. This is because it would cause many problems in a full organ: the cells would not attach with eachother, they would not cooperate with eachother, and they would be worn already (meaning their life expectancy is severely lowered). It is necessary to use stem cells, or pleuripotent cells that will mature into the form that they are processed in.
The types of stem cells that are used in bioengineering are reviewed in a very eloquent paper by Trounson titled: Stem cells in biology, tissue engineering and medicine:
the leading edge keeps moving.
The paper discusses how each type is allowing the progression of bioengineering, and medecine. Induced Plueripotent Stem cells (iPS) are discussed as a great way to turn any mature cell back into a stem cell, which allows for personalized stem cells to be made out of any cell in our body. We could effectively take a cheek swab and grow a kidney! This is the power of iPS, and happens to be the most useful way to engineer something that will be "exactly what the doctor ordered". Imagine having a heart that is exactly like your heart, from your cheek cells! The thought is mind-blowing, but the possibility is there.
Stem Cells & Bioengineering
