Potentiometric urea biosensor based on immobilization of urease onto molecularly imprinted TiO2 film

A novel potentiometric urea biosensor has been developed for selective and quantitative recognition of urea by immobilizing urease onto Ti/urease-imprinted TiO2 film and monitoring the potentiometric response caused by the immobilized urease/urea reaction system. Urease immobilization on TiO2 film was investigated using a potentiometer, and factors affecting its immobilization such as concentration of urease, pH and ionic strength were discussed in detail. The performance of the developed urea biosensor was evaluated, and the obtained urea biosensor exhibited shorter response time (25 s), wider linear range (8 μM–3 mM), lower detection limit (5.0 μM) and good stability (with about 93.3% of the original response signal retained after 1 month). The clinical analysis of the urea biosensor confirmed the feasibility of urea detection in urine samples.