doi:10.1038/nindia.2017.158 Published online 22 December 2017
Researchers have invented a fast, sensitive optical sensor that can be used to detect urea in human blood and various environmental samples1.
Urea, a major organic waste product of living organisms including humans, is excreted through the urine. An excessive level of urea is potentially harmful because it can break down DNA and protein molecules, triggering diseases such as diabetes, kidney failure and sepsis.
Existing methods for detecting urea cannot efficiently monitor urea concentrations in a wide range of biological and environmental samples.
To make a fast-response, versatile urea sensor, scientists from the Indira Gandhi Centre for Atomic Research, Kalapakkam in India, led by John Philip, made an oil-in-water magnetic nanoemulsion using iron oxide nanoparticles, polymers, a surfactant and water. They then explored the nanoemulsion’s potential to sense urea in a solution.
The magnetic nanoemulsion selectively detected urea even in the presence of positively charged interfering ions that are usually found in human blood, such as calcium and sodium. The nanoemulsion detected urea very rapidly, about 100 times faster than conventional crystal-based sensors.
It is possible to tweak the concentration of the oil droplets in the nanoemulsion, making it exhibit a colour change in the presence of urea. This, in turn, helps detect urea with the naked eye. The urea sensor is non-enzymatic and can detect urea in a wide range of samples, says principal researcher Philip.
1. Zaibudeen, A. W. et al. Magnetic nanofluid based non-enzymatic sensor for urea detection.Sensor. Actuator. B. Chem. 255, 720-728 (2018)