Urease Enzyme Biosensor for Water Pollution Detection

Abstract

Urea is the most nitrogen-containing substance in the urine of mammals. It plays an important role in the metabolism of nitrogen-containing compounds in animals and humans. A biosensor for urea was made by immobilizing urea enzyme and bromo stain, both obtained from Sigma-Aldrich Company, on the microparticales surface. They were prepared through encapsulation successively by the LBL self-assembly process of polyelectrolyte using PASS and PAH polymers in eight layers. The size of nanoparticales was 5.05–5.87 nm. In another case, some of these microparticales were removed from their cores by HCL acid and filled with Bromo stain, which is sensitive to changes in PH. The microparticales were prepared and determined there size, layers under the SEM microscopy. The temperature, PH buffer concentration, urine enzyme concentration, and enzyme immobilizing procedure were investigated. Microparticales prepared with urine enzyme give a highly sensitive response time 1-2 min. This biosensor can be used to determine pollution in water, and these microparticules make it possible for biosensors to carry inside many medical materials in the future.