Now, a battery running on urine

Research team leader Ki Bang Lee with the urine-activated battery.  

Anand Parthasarathy

BANGALORE: Soon, you may not require a separate power source for the disposable kits used to test your urine sample: researchers at Singapore's Institute for Bioengineering and Nanotechnology have developed a world-first battery that is activated by the urine under test.

In a paper to be published in the September issue of the Institute of Physics' Journal of Micromechanics and Microengineering, research team leader Ki Bang Lee reports that with just one fifth of a milli-litre of urine, they were able to generate 1.5 volts (same as a standard pen light cell) with a power equivalent to 1.5 milliwatts.

The battery consists of a plastic film-encased sandwich, just one mm thick, containing paper steeped in copper chloride, and strips of magnesium and copper as the positive and negative terminals. The battery powers on when it contacts the urine sample.

In a special e-mailed communication to The Hindu , Dr. Lee suggests that the paper battery and sensors can be integrated on a plastic card, less than the size of a credit card, to make a cheap disposable biochip for disease detection. A drop of urine placed on the battery will generate enough electricity to power the biochip which can then analyse the sample for specific disease markers, he says.

Asked how soon his team expected to see the technology harnessed in a product that might reach the consumer, Dr. Lee said commercialisation of a fully integrated biochip was still some time away.