Tissue engineering: growing new organs, and more

In the 1970s and 1980s, tissue engineers began working on growing replacement organs for transplantation into patients. While scientists are still targetting that goal, much of the tissue engineering research at MIT is also focused on creating tissue that can be used in the lab to model human disease and test potential new drugs.

This kind of disease modelling could have a great impact in the near term, says MIT professor Sangeeta Bhatia, who is developing liver tissue to study hepatitis C and malaria infection.

Like other human tissues, liver is difficult to grow outside the human body because cells tend to lose their function when they lose contact with neighboring cells. ''The challenge is to grow the cells outside the body while maintaining their function after being removed from their usual microenvironment,'' says Bhatia, the John and Dorothy Wilson Professor of Health Sciences and Technology and Electrical Engineering and Computer Science.

Bhatia recently developed the first stem-cell-derived liver tissue model that can be infected with the hepatitis C virus. She has also designed thin slices of human liver tissue that can be implanted in mice, enabling rapid studies of potential drugs.

In a large-scale project recently funded by the Defense Advanced Research Projects Administration, several MIT faculty members are working on a ''human-on-a-chip'' system that scientists could use to study up to 10 human tissue types at a time. The goal is to create a customisable system of interconnected tissues, grown in small wells on a plate, allowing researchers to analyze how tissues respond to different drugs.

''If they're developing a drug for Alzheimer's, they may want to examine the uptake by the intestine, the metabolism by the liver, and the toxicity on heart tissue, brain tissue or lung tissue,'' says Linda Griffith, the S.E.T.I. Professor of Biological and Mechanical Engineering at MIT and leader of the research team, which also includes scientists from the Charles Stark Draper Laboratory, Zyoxel and MatTek.