August 17, 2005 – Scientists at the Institute of Bioengineering and Nanotechnology (IBN) in Singapore have developed the first urine-activated paper battery for use in biochip devices. This battery could potentially be the perfect power source for cheap, disposable healthcare test-kits for diseases such as diabetes. While researchers around the world race to produce ever smaller and more effective diagnostic biochips that can be mass produced cheaply, they have been unsuccessful in finding a power source that is as small and as cheap to fabricate as the detection technology itself. IBN’s latest invention solves this problem by using the urine test sample as the power source for the testing device. The chemical composition of urine is widely used to test for signs of various diseases and as an indicator of a person’s general state of health.
For example, the concentration of glucose in urine is a useful diagnostic tool for diabetics. According to IBN Principal Research Scientist Dr. Ki Bang Lee who heads the team, a drop of urine placed on the battery will generate enough electricity to power a biochip device, enabling the latter to analyze the urine sample for specific disease biomarkers.
“We are striving to develop cheap, disposable credit card-sized biochips for disease detection,” said Dr. Lee. “Our battery can be easily integrated into such devices, supplying electricity upon contact with biofluids such as urine.”
IBN’s battery unit comprises of a cathode sandwiched between an anode and an electron-collecting layer. This multi-layer unit is then held in place via a lamination process, which involves passing the battery unit between a pair of transparent plastic films through a heating roller at 120ºC. The final product has a dimension of 60 mm x 30 mm, and a thickness of 1 mm. Studies have been conducted to characterize the urine-activated battery. Using 0.2ml of urine, IBN researchers were able to generate sufficient voltage to power the device and conduct effective analysis of analytes in the biofluid (urine).
They also found that the battery performances such as voltage, power or duration may be designed or adjusted by changing the geometry or the materials used. “Our urine-activated battery would be integrated into biochip systems for healthcare diagnostic applications,” said Dr. Lee. He envisions a world where people will be able to monitor their health easily at home, seeking medical attention only when necessary.