Researchers have developed a sensitive, self-powered sensor using a paper-based microbial fuel cell1. This sensor can detect minute traces of alcohol, making it potentially useful in industrial set-ups.
Existing techniques for detecting alcohol are expensive and complex. To date, there are no portable and low-cost commercial devices for the selective and quantitative detection of alcohol.
To design a cheap and efficient sensor for detecting alcohol, scientists from the Indian Institute of Technology in Guwahati, India, first fabricated a microbial fuel cell using a graphene- and silk-based nanocomposite, and a biofilm of photosynthetic bacteria. The team, led by Pranab Goswami, then made the sensor by transferring the fuel cell onto a paper-based platform.
On adding alcohol to the sensor, the alcohol degraded the bacterial cell membrane. This led to the transfer of electrons through protein channels in the bacterial membrane and then across the fuel cell. This, in turn, caused an increase in potential that increased on raising the concentration of the alcohol. This generated a detectable signal.
The sensor exhibited a response time of 10 seconds, with the efficiency to detect as low as 0.02 per cent alcohol. The sensor was more sensitive to ethanol than to methanol.
The portable and low-cost ethanol sensor has lot of potential in the booming bioethanol production and fermentation industries, especially in north-east India, where the preparation of alcoholic brews is widely practised, says lead author Sharbani Kaushik.
