Combining tissue engineering and the same micro-fabrication techniques that are used to produce computer chips, Harvard University cell biologist Don Ingber and his colleagues have built a living, breathing synthetic lung—albeit one just the size of a quarter.
Last June Ingber’s team reported that it had placed human lung lining cells and human capillary cells on either side of a porous, flexible polymer membrane. As the two cell types exchanged air and nutrients through the membrane, the researchers used on-and-off suction to make it expand and contract, mimicking a lung’s natural movement. “The whole thing breathes, just like we do,” Ingber says.
This lung-on-a-chip could someday replace animal testing, Ingber suggests. His team has shown that the synthetic lung responds to pathogens much like the real thing does. After “inhaling” E. coli, for instance, the lung attracted human white blood cells to attack and kill the bacteria, a process scientists have long understood but never before witnessed in vitro. Other, noninfectious nanoparticles traveled across the membrane interface, showing that the laboratory-
created lung also reacts much like a live lung to air particulates.
Ingber and his colleagues are working on analogous models of other organs, too, including a beating heart and a gut capable of a peristaltic wave. Could a “human-on-a-chip” be very far behind?