Developing a urea biosensor and safe blood cleaning method utilizing a novel high throughput La-doped CeO₂ nanosized...

Herein, a urea biosensor and safe blood cleaning method utilizing a novel high throughput La-doped CeO₂ nanosized artificial urease with high biocompatibility and enzyme-like activity were developed. The urease-like activity, stability composition, morphological characteristics, size, biocompatibility, and crystalline characteristics of the artificial urease were assessed. Considering its high urease-like activity, it is applied for both urea biosensing and safe blood cleaning. The effective factors on the sensing conditions were optimized, providing a wide linear range over 1-10 µM and a low detection limit of 0.5 µM. The repeatability and reproducibility assessments revealed a %RSD of 1.7 % and 2.7 %, in order. The selectivity studies and real blood analysis revealed highly selective, accurate, and reliable determination of urea in biosamples using the developed method, providing a %recovery of 97.8-99.5 % with a low %RSD range of 1.4-3.3 %. Besides, the safe blood cleaning experiments were also performed by urea mineralization from blood. The results exhibited a high blood cleaning yield of 99.5 % at a short time of 30 min, revealing 1.8-fold higher cleaning efficiency for the artificial urease compared to native urease. The reusability studies showed that the blood cleaning yield was saved for about 10 cycles and then it decreased by increasing the operational cycles, reaching 78.6 % after 17 cycles. The shelf-life of the urease was also evaluated within 30 days, revealing a high shelf-stability for the as-prepared nanosized artificial urease. Consequentially, the nanosized artificial urease can be practically applied for both urea detection and blood cleaning in the real world.