People power17th October 2011
Artificial organs almost always require electricity to work, but a new technology can power them using the body's own metabolic energy, according to a recent Swiss study.
The Swiss researchers implanted the device, which is the size of a grain of rice, in rats, and found it still worked flawlessly after 40 days.
Theoretically, a working version of the device would be as long-lived as any other bodily organ.
Currently, electrical implants such as pacemakers need to be replaced about every five years.
Lead researcher Serge Cosnier said that implanting the device in a rat was a good way to prove that biofuel cells could be made to work, although rats did not produce much electricity internally.
He said that his team's next project would be to implant the device in a cow.
The structure of the device is not complicated, consisting of two electrodes, one of which removes electrons from glucose.
The second electrode is able to add an electron to oxygen and hydrogen molecules, which prouces water.
Taken together, the two electrodes can produce electrical currents, and powering any device using that current should be as simple as putting it in-between those electrodes.
Although the device is designed to receive electrodes from human metabolism, the cell does not need to be located inside a human body to work.
Cosnier said that people living in regions where there was no electrical supply would eventually be able to power electrical appliances using the technology, simply by adding sugar and water.
Sony recently announced that it had produced a glucose-powered electrical cell with enough electrical current to make a portable audio player work.
Cosnier said that biofuel cells could theoretically work without limits, due to the fact that glucose and oxygen were constantly being replenished by the body itself.
Although scientists have spent the past 10 years trying to engineer biofuel cells, it has only recently become possible to make them.
Advances in carbon nanotube technology are partly responsible for the new biofuel cells, as are scientists' understanding of enzyme reactions.
In particular, scientists have found that the enzyme glucose oxidase is extremely good at removing electrons from glucose, and that enzyme is one of the main constituents of the new technology.
In order to construct the device used in the recent study, researchers first mixed carbon nanotube paste with the enzyme glucose oxidase.
Then they set some of it aside, and mixed the rest with another enzyme, known as polyphenol oxidase.
The glucose oxidase mixture acts as one electrode, removing electrons from glucose molecules, and the polyphenol oxidase as another, adding electrons to hydrogen and oxygen.
The entire artificial organ is wrapped in a combination of special materials, which hide it from the body's immune system, as well as stopping it from falling apart.
Itamar Willner, a professor and researcher at the Hebrew University of Jerusalem, who was part of the advances in biofuel cell technology that inspired the recent Swiss study, said that he was confident that the next decade would see exciting developments in biotechnology.
He said the next 10 years may see biofuel cells in laptops and mobile phones.
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Title: People power
Author: Luisetta Mudie
Article Id: 20081
Date Added: 17th Oct 2011