The Indian Institutes of Technology, Bombay and Indore, have jointly developed a biosensor that makes it possible to detect kidney disorders in less than eight minutes.
The biosensor can accurately measure both the pH and urea concentration with a single drop of urine. The researchers who developed it say that it will help make a point-of-care test to determine whether the kidneys are functioning normally.
For a kidney function test, doctors need an estimate of pH and urea as most kidney disorders result in reduced pH and higher concentration of urea. Available methods to detect urea require patients to undergo two tests for accuracy. In addition, there is the problem of contaminating components in urine such as calcium, chloride, ascorbic acid, sodium and potassium.
How it works
The biosensor, developed by Rashmi Chaudhari, Abhijeet Joshi, and Rohit Srivastava, can detect both and is made by encapsulating an enzyme urease and a molecule FITC-dextran in alginate microspheres. The combination glows in response to a chemical reaction with urea and changes in pH when urine is added. The fluorescence reduces when the pH is acidic and increases when it is alkaline. The changes in fluorescence intensity are measured, which helps to calculate the values of pH and urea.
“It is made using alginate which is safe and non-toxic to handle. It can work in the ideal pH range of 4-8, and is able detect even low concentrations of urea up to 50 millimolar,” Ms. Chaudhari told India Science Wire.
Abhijeet Joshi, a coauthor and on the faculty at IIT-Indore said, “We tested the biosensor on samples of patients suffering from chronic kidney disease procured from KEM Hospital and Apex Kidney Care [both] in Mumbai and it showed an accuracy of more than 97%.”
Rohit Srivastava, professor, Department of Biosciences and Bioengineering, IIT-Bombay, who led the study, added that “the biosensor is stable for up to a month in a refrigerator and gives results that are unaffected by other components in urine samples”. It will help make a rapid and accurate point-of-care diagnostic test for kidney disorders.
However, Bansi D. Malhotra, professor, Department of Biotechnology at the Delhi Technological University, who is not connected to the study, said that while the biosensor uses fluorescence-based technique to detect urea in urine sample, “it is not user-friendly and as cost-effective when compared to other (electrochemical) techniques, which are routinely used for this purpose”. — India Science Wire
