The scientists started with a mesh of silicon wires coated in an organic polymer, each 30 to 80 nanometers in diameter. The mesh is three-dimensional, like a sponge, and can be bent into any shape. Next, the scientists seeded the mesh with living cells that were grown in a culture. The result was living cells with a three-dimensional mechanical support able to carry electrical signals. While two-dimensional scaffolds have been made before, those don't replicate what happens in the human body, where cells are in three-dimensional structures.
Thus far the team has engineered cyborg tissues using heart, muscle, blood vessel and nerve cells. The cells' viability and activity wasn't affected. The embedded sensory circuits were able to pick up electrical signals generated by the cells in response to drugs. In the case of the blood vessels, the circuits detected pH changes, which could be useful in tracking inflammation.
None of these pieces of tissue has been implanted into a human being yet; it will be some time before the technology gets to that point.
The team was led by Charles M. Lieber, a professor of chemistry at Harvard and Daniel Kohane, a Harvard Medical School anesthesiologist. Kohane developed the "scaffolds" for the cells. Other contributors were Robert Langer from the Massachusetts Institute of Technology, and Zhigang Suo, professor of mechanics and materials at Harvard. The work was published Aug. 26 in Nature Materials.
Credit: Charles M. Lieber and Daniel S. Kohane, MIT