Researchers have designed a sensor to detect urea by trapping live bacterial cells in a conducting polymer1. The reusable sensor could be very handy in detecting blood urea levels.
During abnormal physiological conditions, blood urea levels shoot up. To devise an effective technique to detect urea, the researchers trapped bacterium Brevibacterium ammoniagenes in polystyrene suphonate-polyaniline (PSS-PANI) conducting polymer on a platinum twin wire electrode.
Bacterial cells retained their viability as well as urease activity in an entrapped state. The bacterial urease catalysed the hydrolysis of urea into carbon dioxide and ammonia. The catalytic action of urease in the sensor released ammonia increasing the hydrogen ion concentration of the microenvironment. This led to change in resistance of the conducting polymer – the basis of the sensing mechanism.
The sensor could be reused for 12–15 independent measurements and was quite stable in dry as well as buffered storage condition at 4 °C for at least 7 days, the researchers say.
The authors of this work are from: Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research Centre, Mumbai, and Department of Chemistry, Indian Institute of Technology, Mumbai, India.
