The recent discovery by a team of Indian scientists based in Bangalore, which revealed carbon nanotube flow sensors that generate electric current when placed in moving liquid, promises to have enormous applications in the biomedical field.

The tiny sensors, made out of bundles of carbon nanotubes, can be used as an energy conversion device. The sensors, which do not incorporate any moving parts and considered a possible advance for the 'lab on a chip', were built by Prof. Ajay K. Sood, Professor of Physics at the Indian Institute of Science (IISc) along with N Kumar of the Raman Research Institute and Shankar Ghosh, an IISc student.

"If you have a flowing environment and if you put the sensor, you get voltage/current out of it. If you put it in a biomedical environment, you can get voltage/current out of it that can be used for therapeutic purposes for the body itself," says Prof. Sood.

Prof. Sood said the team had applied for patents in the US and India as they believed that "all the indications are that the sensorhas immense potential".

Stating that the flow of a liquid on single-walled carbon nanotube (SWNT) bundles induces a voltage/current, Prof Sood said the magnitude of the voltage/current depends sensitively on the ionic conductivity and the polar nature of the liquid.

According to him, the sensor can be scaled down to length dimensions -- microns, the length of the individual nanotubes making it usable in very small liquid volumes. The sensor also has high sensitivity at low velocities, and a fast response time, he said, adding, it can detect very small velocities.