Single-enzyme nanoparticles based urea biosensor

Single-enzyme nanoparticles (SENs) with excellent activity and stability were successfully fabricated via the surface modification and in situ aqueous polymerization of separate urease molecule. A novel piezoelectric biosensor was developed for urea determination based on SENs immobilization onto nanoporous alumina membranes prepared by electrical anodization. The process of SENs immobilization was optimized and the performance of the developed urea biosensor was evaluated. The high selectivity, shorter response time (12 s), wider linear range (0.08 μM–1 mM) and lower limit of detection (LOD, 0.05 μM) were observed for the present biosensor. Moreover, a stability study showed a very high stability over time for the frequency response of the biosensor with separated porous alumina/SENs electrode, testifying for the protective nature of the nanoporous alumina membranes and the interest of SENs. The clinical analysis of the urea biosensor confirmed the feasibility of urea determination in urine sample.