ElectricSteve writes "Utilizing human lung and blood vessel cells, researchers have created a device mounted on a microchip that mimics a living, breathing human lung. About the size of a rubber eraser, the device was developed by a team from the Wyss Institute for Biologically Inspired Engineering at Harvard University, Harvard Medical School, and Children's Hospital Boston. Because it's translucent, researchers can watch the processes taking place inside of it — something that's difficult to do with an actual lung. It will be used for testing the respiratory effects of environmental toxins, aerosolized therapeutics, and new drugs. Using conventional models, such tests can cost more than $2 million."