© Photographer: Andres Rodriguez

Other Types of Bio-Batteries

It's not just researchers at the Rensselaer Polytechnique Institute who are working on bio-batteries. Many other corporations, universities and research foundations are competing to produce viable batteries that can be powered off of organic compounds, especially human fluids. Researchers consider sugar and human blood glucose potentially valuable sources of power because they occur naturally, are easily accessible and don't produce harmful emissions.

In 2003, Japanese researchers at Panasonic's Nanotechnology Research Laboratory announced that they were working on extracting power from blood glucose. At the time, they were using enzymes -- a frequent component of bio-batteries due to their catalytic properties -- to retrieve electrons from glucose. Two years later, a different Japanese research team, this one from Tohoku University, announced that they had succeeded in creating a small "biological fuel cell." Their cell could be used to power small medical devices, such as an implant to measure blood sugar levels in diabetics. Future versions of such technology could, like RPI's nanocomposite paper, be used to power an artificial heart with the blood that flows through and around it.

In August 2005, scientists in Singapore developed a battery that uses human urine as its fuel. Despite its potentially off-putting power source, the battery has a wide variety of applications. The researchers said that their device was the size of a credit card and could form the basis of inexpensive, disposable disease-testing kits. (Urine is already used to detect drugs and some diseases.) What makes the device particularly useful is that it integrated the battery and testing device into one disposable chip. Imagine a one-time use home-testing kit for diseases like cancer or hepatitis. One of the researchers involved in the project said that the battery could also be adapted to provide a brief charge to other electronic devices. A lost hiker might use one to power a cell phone for a short emergency call.

Electronics giant Sony announced in August 2007 that it had also created a battery that derives energy from sugar. One demonstration showed the small battery extracting energy from a glucose solution. In another demonstration, the battery sipped on a sports drink for power.

If urine-powered or sports drink-sipping batteries were not strange enough, a South Korean research team may have produced one of the strangest of all bio-devices in September 2007. These scientists produced "crab-like microrobots" made out of genuine living tissue. They made the tiny robots by extracting tissue from neonatal rat hearts and growing it on miniscule 'E'-shaped skeletons. These heart cells then "pulsated" for more than 10 days, allowing the robots to move up to 50 meters [source: Primidi.com]. With the right refinements, these microrobots could be used to clear away blockages in arteries.

While many exciting announcements have been made in the field of bio-batteries, it may be some time before we see them replacing nickel-cadmium, lithium-ion or the several other types of traditional batteries. Even so, the small, flexible, long-lasting and environmentally friendly battery technologies discussed here show the great possibilities researchers see in bio-batteries, especially for the field of medicine. With that in mind, scientists seem to be exploring every possible option in bio-battery and fuel-cell technology: One research team even devised a fuel cell that ran off of gin and vodka.

For more information about bio-batteries and other related topics, including some of the many types of batteries, please check out the links on the next page.