May 20, 2010

Humans And Machines Closer To Compatibility

A new transistor controlled by the molecule that powers biological cells is bringing humans and machines one-step closer to merging.

The device could be used in medical devices or prosthetics wired directly into the human body because of its nano-scale size.

"Our devices make a bridge between the biological world and the electronic world," Aleksandr Noy, who developed the transistor along with colleagues at Lawrence Livermore National Laboratories in California, told MSN News.  "In effect, we made a biological protein talk directly with a nanoelectronic circuit."

Transistors are electronic components that modulate or switch a current on and off.  Noy and his team borrowed from living cells in order to make a transistor that would respond to biological molecules.

They first built the backbone of the transistor out of a carbon nanotube between two electrodes.  After that, they insulated the electrodes and covered the nanotube with a mixture of fatty molecules called lipids and proteins.  The covering formed a lipid "bilayer" much like those that make up the outer membranes of biological cells.

The team then poured a solution of sodium ions, potassium ions and adenosine triphosphate, or ATP, over the transistor while running a voltage through it.  ATP is the primary source of energy in cells.  It fulfilled the same role as the transistor, powering the proteins embedded in the lipid bilayer.

These proteins started working by transferring sodium and potassium ions across the bilayer.  The charges from the ions created an electrical field around the transistor, which then changed the ability of the transistor to conduct electricity by about 35 percent.  The higher the concentration of ATP, the more the conductivity changed.

Noy told TechNewsDaily that getting a biological molecule to control the electric current in a transistor is a first step toward computers that would interface directly with the brain.


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