Viridian Note 00313: Internal Biofuel CellsBruce Sterling [firstname.lastname@example.org]
Key concepts: fuel cells, glucose, bloodstreams, injectable mechanisms, alternative power sources
Attention Conservation Notice: Viridian gizmo alert.
(((Tiny, internal fuel cells run off your body chemistry. Boy, this one is weird. I have no time to comment on this story at the extensive length it deserves, as I'm leaving soon for Europe for almost two weeks. But check out those links.)))
"TECHNOLOGY: Biofuel Cells by Robert F. Service
"While companies are battling to shrink fuel cells down to cell phone size, nature has already done them one better. Enzymes in creatures from bacteria to people extract energy from compounds such as glucose to power life. Now researchers are looking to borrow a page from biology's manual to create rice grain-sized fuel cells that run on chemicals inside our bodies. (((Aieee!))) Such cells, they say, could someday power futuristic implantable sensors that monitor everything from blood glucose levels in diabetics to chemicals that signal the onset of heart disease or cancer. (((And why stop there? Why not power tiny Microsoft X-boxes?)))
"Researchers can already make glucose-detecting sensors as small as a millimeter across. 'But you cannot make a submillimeter-sized battery at a reasonable cost,' says Adam Heller, a chemical engineer and biofuel cell pioneer at the University of Texas, Austin. 'That's where we see the use for miniature biofuel cells.' (((Good Lord, that's just down the street from the Viridian Vatican!)))
"Biofuel cells are much further from commercial development than their larger cousins. (((Whew!))) But recent progress has been heady. Last August, for example, Heller and his Texas colleagues reported in the Journal of the American Chemical Society that they had created a miniature glucose-powered cell that puts out 600 nanowatts of power, five times the previous biofuel cell record and enough to power small silicon-based microelectronics. Heller's lab has already developed millimeter-sized glucose sensors, which are currently being commercialized by a company called TheraSense in Alameda, California. And the new biofuel cells may one day keep such implantable sensors running for days to weeks at a time."
"Like traditional fuel cells, biofuel cells use catalysts at two oppositely charged electrodes (...) (((etc etc etc)))
"Heller's cells do have their drawbacks. Because laccase enzymes typically work best in environments much more acidic than the neutral pH of blood, laccase-based fuel cells implanted in the body likely wouldn't produce much power. 'Nature didn't evolve proteins to work with circuitry,' says Tayhas Palmore, a chemist at Brown University in Providence, Rhode Island. (((Nice soundbite, ma'am.)))
"But Palmore has been working to improve matters here as well. At a fuel cell conference in Washington, D.C., last month, Palmore reported that her group had used standard molecular biology techniques to reengineer the laccase enzyme so that it retains about 50% of its activity at physiological pH. And Palmore and her colleagues are now working on incorporating the reengineered laccase into a prototype fuel cell that could extract power from circulating fluids such as blood. (((Including somebody else's blood, presumably.... Maybe you can run your 802.11 network off the glucose-charged bloodstreams of small, heyperactive, neighborhood children.)))
"All biofuel cells still face considerable challenges, however. Most important, blood and other complex bodily fluids contain numerous compounds that can deactivate or block the enzymes essential to fuel-cell function, causing them to stop working within hours or days. But if researchers can improve their stamina, biofuel cells could pave the way to a new generation of implanted devices powered by the body itself."
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