You needn't flush your urine away anymore. Dr Ki Bang Lee, of Singapore’s Institute of Bioengineering and Nanotechnology, has devised a paper battery that uses urine to provide energy for the device being used for testing. Presently, lithium batteries are used for powering home-urine-testing kits.
The battery comprises a strip of paper dipped in copper chloride and placed between magnesium and copper strips. While testing the battery, researchers generated a voltage of around 1.5 V and a power of 1.5 mW through 0.2 ml urine. This new battery can be used to charge mobile phones also.
“We are striving to develop cheap, disposable credit-card sized biochips for disease detection. Our battery can be easily integrated into such devices, supplying electricity on contact with biofluids such as urine or blood,” said Dr Lee. It measures 60 by 30 mm and is one mm thick.
Even though the battery can be used to charge small disposable systems, more work is required before a similar battery can be designed for larger electronics like laptops and iPods. “But if, for example, we place a small cellular phone or transmitter on a plastic card, the chip will work as a disposable biofluid-activated means of communication in an emergency. In this case, the size will be less than that of a credit card,” Dr Lee said.
According to the physicist, the new design overcomes many obstacles encountered while trying to bring down the size of regular batteries for use with bioMEMS (bio-microelectromechanical devices).
“Many researchers have tried to design power sources or batteries for systems or bioMEMS devices. However, they have done this by reducing the size of conventional, bulky power systems or batteries. They faced a lot of problems (like generating enough electricity),” the researcher said.
He added that further improvement in design could help increasing the voltage and power of the new battery as can changing the electrolyte and electrode used. But for now, the priority is to develop home-test kits for testing urine and other biofluids easily. “The long-term goal is for people to be able to buy disposable biochips for a disease test from any pharmacy,” Dr Lee said.
The details of the new battery have been published in the
Journal of Micromechanics and Microengineering.
