In 2001, [Dr. Doug Smith from the University of Pennsylvania] and colleagues developed a way to grow new lengths of nerve fibre by gradually pulling apart groups of connected neurons . . . Lengths of nerve generated in this way, and measuring up to 10 centimetres, have already been used to fix damaged nerves in the limbs of human patients.Tests already show that electrical signals can be transmitted in both directions along cords made in this fashion. Dr. Smith says such cords could be used to connect a person's nervous system to a computer. In the future, he adds, the cords might be used to connect an amputee's nerves to prosthetics or even to hook up artificial eyes or ears to someone's brain.
The data cables are created in the same way. A group of neurons is cultured on top of an array of 96 electrodes covered with a protein coating that causes them to attach. When placed 100 microns (about the width of a human hair) from another patch of neurons on a separate plate, the cells grow towards them, eventually joining neuron clumps together. . . . A motor is then used to slowly draw the two plates apart – causing the nerve fibres to continuing growing, at up to 1 cm each day.