Scientists devise part-human, part-machine transistor

Thursday, June 3, 2010

WASHINGTON - Scientists have implanted a nano-sized transistor inside a cell-like membrane and powered it using the cell’s own fuel, paving way for new types of man-machine interactions.

The experiment is believed to be the most intimate linking between man and machine till date.

The technology may help experts learn the inner workings of disease-related proteins inside cell membranes, which would lead to new ways to read and control brain or nerve cells.

Aleksandr Noy, a scientist at the University of California, Merced who is a co-author on the recent ACS Nano Letters, said: “This device is as close to the seamless marriage of biological and electronic structures as anything else that people did before.

“We can take proteins, real biological machines, and make them part of a working microelectronic circuit.”

The experts created the implanted circuit with a simple transistor. The scientists used a next generation material known as a carbon nanotube for the transistor, instead of most commonly used silicon.

The scientists then coated the carbon nanotube transistor with a lipid bilayer, basically a double wall of oil molecules that cells use to separate their insides from their environment. The scientists didn’t use an actual cell membrane, however.

To this basic cellular structure the UC scientists added an ion pump, a biological device that pumps charged atoms of calcium, potassium, and other elements into and out of the cell. Then they added a solution of adenosine tri-phosphate, or ATP, which fuels the ion pump.

The ion pump changes the electrical charge inside the cell, which then changes the electrical charge going through the transistor, which the scientists could measure and monitor.

In their initial device the biological pump powered the artificial transistor. Future devices could work just the opposite, where an outside electrical current could power the pump and alter how quickly ions are pumped into or out of a cell. That could have dramatic effects.

For instance, instead of using drugs to block the release or uptake of various drugs or neurotransmitters, scientists could change the electricity regulating the ion pump, which would then change the amount of the drug or molecule inside, or outside, the cell.

Other groups have tried to mix man and machine before, said Itamar Willner, a scientist from the Hebrew University of Jerusalem, but none have achieved this level of intimacy.

“Previous students used enzymes that were not incorporated into membranes in the transistors. In this case, an enzyme that usually works in the membrane was linked to carbon nanotubes,” Discovery News quoted Willner, as saying.

The new enzyme-transistor link could help eventually monitor and even treat diseases and conditions, said Willner.

Willner said: “We don’t want to just sense things, we also want to treat them. Clinical applications may still be years away, but the new research is the most intimate link between life and machines that has yet been created.”

The study has been published in the journal ACS Nano Letters. (ANI)

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