Commentary: field of tissue engineering is progressing at remarkable pace

What many didnt realise was that the freaky looking ear was never grown, had nothing to do with genetic engineering and wasnt really a scientific breakthrough at all! Instead, it served as the publics introduction to the new field of tissue engineering, through which researchers attempt to create replacement tissues in the laboratory by combining resorbable materials with stem cells.

Tissue engineers, like those in my laboratory at Kings College London, work to build everything from cartilage to fix creaky arthritic knees to coronary arteries to patch up heart patients. What looked like a human ear grown on a mouse was simply what we call a scaffold, an implantable 3D structure made of a plastic that safely dissolves in the body.

Twenty years later, a UCL-based team led by Dr Patrizia Ferretti is continuing to build on this work to reconstruct ears. Surgeons currently treat microtia, a condition in which children are born with a malformed or missing ear, by taking cartilage from the patients rib and implanting it in the head to form something that looks like an ear.

Dr Ferretti hopes to eliminate the need for this second cartilage-harvesting surgery by growing ear cartilage in the laboratory.

The difference here is that whereas in the 1990s tissue engineers thought that merely forming a scaffold of the correct shape and size would allow us to create a tissue, we now understand that a stem cells perception of its nano-environment plays an important role in determining the tissue it creates.

In short, we can now tailor a scaffold with nano-cues that tell a stem cell to become a liver cell instead of lung.

Dr Ferrettis scaffold does just this. Her team utilises a new nanocaged POSS-PCU scaffold to coax stem cells collected from fat to form cartilage whilst the scaffold slowly melts away.

This exciting material came to light in 2011 when it was used to replace the windpipe of a patient who had to have his own removed because of cancer.

The scaffold here instructed stem cells to create the windpipes lining, essentially using the body as an incubator to help direct their fate. This time, the UCL team utilised a cocktail of chemicals to help push the stem cells to make cartilage, so it remains to be seen if the scaffold will similarly drive ear cartilage formation once placed in the body.

What is clear, however, is that the field of tissue engineering is progressing at a remarkable pace and tailor-made tissues to treat a range of conditions are a real possibility in the near future."

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Commentary: field of tissue engineering is progressing at remarkable pace