You may not soon be able to refuel your car with corn syrup or charge a computer by plugging it into a bottle of Coca-Cola. But to Stanley Kravitz and a group of researchers at Sandia National Laboratories, sugar looks like the new oil.
Kravitz and his colleagues have begun to apply for patents covering ways to convert glucose, a basic form of sugar, into energy. Glucose seems an obvious potential source for fuel. It is renewable, cheap, abundant and, it would appear, easier to obtain than another alternative, hydrogen.
"The problem with hydrogen is that it isn't just found in the air or lying around," Kravitz said. "You have do something quite energy-intensive to break apart some molecule in order to get hydrogen. That's the Catch-22."
So why aren't other researchers trying to power their fuel cells with glucose rather than hydrogen? Glucose molecules, it turns out, are not easily persuaded to give up their energy.
Over time, naturally occurring enzymes have turned mammals into glucose-burning machines. The human body, for example, metabolizes glucose in a delicately choreographed dance. Twelve different enzymes partner in succession with the glucose molecule, each enzyme sending two electrons spinning offstage into cellular power sources and thereby fueling the body.
One approach that Sandia researchers are taking is to genetically engineer enzymes that mimic those in the human body. "If evolution figured it out, we should be able to figure it out," Kravitz said. Another approach is nonbiological, using metals like platinum to liberate electrons.
Early potential applications of glucose fuel cells would require only small amounts of energy. For example, security systems to detect movement or the presence of chemicals could use sensors that would be plugged into trees, siphoning glucose from sap for energy.
The Sandia researchers are not the only ones who are converting glucose to energy. Adam Heller, a professor at the University of Texas and a founder of TheraSense, a manufacturer of blood-glucose monitoring devices that was acquired in April by Abbott Laboratories, recently received U.S. Patent No. 6,531,239 for a glucose fuel cell.
Last year, Heller and colleagues published a paper in The Journal of the American Chemical Society describing the tiniest fuel cell ever built in a living organism - in this case, a grape, whose sap provided the glucose fuel. Heller said he might use a similar fuel cell to run a continuous glucose monitor that he is developing. Embedded in a patient's skin for three days, the device would eliminate the daily pricking that most diabetics endure to keep track of glucose levels.