German scientists have developed a technique that hooks up living tissue to electronic circuitry, a discovery that could lead to implants that communicate with the body and hybrid sensors made from biological material and silicon.
‘Having solved the principal problem of coupling cellular electrical signals with silicon electrical signals, we can now proceed to develop cellular biosensors,’ said Peter Fromherz at the Max-Planck Institute for Biochemistry, Martinsried, Germany.
Connecting living cells to silicon circuitry is said to be difficult because cells grown on silicon sheets do not bond to the surface.
Instead they float 40 nanometres above their nutrient solution. Even though the gap is small, it makes it very difficult for electronic devices to detect the weak electrical signals produced by the cells.
Fromherz found a way around the problem by making cells produce larger electrical signals through their ‘ion channels’, gates in the cell membrane that pump out electrical signals.
To boost the signal, he took human kidney cells that have very few ‘ion channels’ and added a gene for a specific type of ion channel capable of conducting large electrical signals.
The result was a group of cells with extra ion channels capable of producing stronger electrical signals.
When Fromherz grew the cells on a silicon transistor he found the transistor could detect and amplify the electrical signals being pushed out of the cells.
Erwin Neher of the Max-Planck Institute for Biophysical Chemistry said that coupling living tissue to electronics in this way could lead to far more sophisticated implants in the future. ‘Intelligent prosthetic devices could be designed that allow two-way communication between their control circuits and the nervous system.’