Development of Amperometric Biosensor Immobilized by Entrapment of Urease Enzyme in Polypiroll Film for the Determination of Blood Urea

Abstract

Accurate determination of blood urea concentration has gained a great clinical interest, especially for diagnosing kidney failure or lever malfunctioning. The biosensor can provide a fast response and accurate measurement about blood urea concentration. In this research, a method for fabrication of a disposable amperometric urea biosensor based on electropolymerization of pyroll was developed. The three electrode configuration fabricated using screen printing method was used namely working electrode made from carbon, counter electrode made from carbon and platinum, and reference electrode made from silver/silver chloride. On the surface of working electrode, urease enzyme was entrapped on a matrix of electrosythesis of polypyrrol film. The urea biosensor was successively verified by cyclic voltammetry. The performance of the urea biosensor had been evaluated with standard urea. The sensor working range was 0.1 mM – 80 mM with a response time less than 10 second and the detection limit of the biosensor of approximately 0.1 mM. The biosensor shows a good stability over a period of 2 months, which is only decreasing to 85% of its initial activity. The influence of the interfering ascorbic acid, uric acid, K + ion and Na + ions on the biosensor shows a little effect on its performance. The urea biosensor had been tested with the serum and the results have been compared with the measurement conducted with spectrophotometer. A good agreement was observed between both the measurements.