Engineering Human Tissue to Construct New Organs

by Alex A. Kecskes

Researchers have been struggling with tissue engineering for some time. The ultimate goal is to construct new organs so patients don't have to wait for transplants.

So far, growing three-dimensional cells has proven quite elusive. But recently, a team at the MIT-Harvard Division of Health Sciences and Technology (HST) say it could be as simple as building "biological Legos." Utilizing a new technique called "micromasonry," these structures would closely resemble real, complex tissue.

Obtaining single cells to engineer tissue calls for breaking tissue apart via enzymes that digest the "glue" holding cells together. Once freed, these cells don't easily reassemble into structures that resemble natural tissue architecture. Using biological Legos, the freed cells are coated with a liquid version of polyethylene glycol (PEG), arranged into cubes and hardened when illuminated to retain a particular shape.

A repeat coating of the cubes with PEG glues the cubes together and squeezes them onto a scaffold surface. A second illumination hardens them into a tube-like shape, providing a three-dimensional structure that can function as capillaries and transport blood to organs. The procedure not only creates 3D structures, but places cells in any desired position to make specific shapes.

While complex tissue architecture has previously been created in a lab (like organ printing, which requires new and costly equipment), micromasonry is relatively simple and can be reproduced in virtually any lab. To make micromasonry clinically viable, different cellular structures and polymers are being explored in hopes of providing more control over cell placement than current PEG techniques.

For an additional perspective, check out this video: