The technique involves creating a network of microscopic tubes that branch out in a pattern, similar to that seen in the circulatory system, to provide oxygen and nutrients to liver or kidney cells that have been cultured in a lab. Using new fractal computational models, the network is designed and etched onto silicon surfaces which are then used as molds to transfer the pattern to biocompatible polymer films. Two films are then sealed together with a microporous membrane sandwiched between them.
"These technologies create a precise architectural framework for the liver or kidney cells that are responsible for the functional replacement of the vital organs," says Mohammad Kaazempur-Mofrad of MIT's department of mechanical engineering and division of biological engineering, lead researcher on the study, whose lab is in charge of designing the networks. Jeffrey Borenstein at Draper Laboratory oversees the microfabrication and polymer processing and the principle director of the entire project is Joseph Vacanti of Massachusetts General Hospital.
Conventional tissue engineering methods have been successful in the creation of new tissues including skin and cartilage, but have failed to create large, functional vital organs such as the kidneys and liver. The reason for this, says Kaazempur-Mofrad, is that while they provide a structural support for the cells of the tissue being created, they fail to provide vascular support (in the form of blood vessels to bring oxygen and nutrients) at the level necessary to maintain the cells of these vital organs. This new process addresses that need.