Researchers at Yale University and the National Institute of Standards and Technology (NIST) describes a highly simplified model cell that not only sheds light on the way certain real cells generate electric voltages, but also acts as a tiny battery that could offer a practical alternative to conventional solid-state energy-generating devices. Each of these cells has a droplet of a water-based solution containing a salt, potassium and chloride ions, enclosed within a wall made of a lipid, a molecule with one end that is attracted to water molecules while the other end repels them. When two of these "cells" come into contact with each other, the water-repelling lipid ends that form their outsides touch, creating a stable double bilayer that separates the two cells' interiors, just as actual cell membranes do.
The researchers also inserted the cell a modified form of a protein, alpha-hemolysin, made by the bacterium Staphylococcus aureus. These embedded proteins create pores that act as channels for ions, mimicking the pores in a biological cell. "This preferentially allows either positive or negative ions to pass through the bilayer and creates a voltage across it," LaVan says. "We can harness this voltage to generate electric current."
http://www.sciencedaily.com/releases/2009/10/091022141402.htm
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