Two-dimensional ytterbium oxide nanodisks based biosensor for selective detection of urea

Herein, we demonstrate synthesis and application of two-dimensional (2D) rectangular ytterbium oxide (Yb₂O₃) nanodisks via a facile hydrothermal method. The structural, morphological, compositional, crystallinity, and phase properties of as-synthesized nanodisks were carried out using several analytical techniques that showed well defined 2D rectangular nanodisks/sheet like morphologies. The average thickness and edge length of the nanosheet structures were 20 ± 5nm and 600 ± 50nm, respectively. To develop urea biosensor, glassy carbon electrodes (GCE) were modified with Yb₂O₃ nanodisks, followed by urease immobilization and Nafion membrane covering (GCE/Yb₂O₃/Urease/Nafion). The fabricated biosensor showed sensitivity of 124.84μAmM^-1cm^-2, wide linear range of 0.05-19mM, detection limit down to ~ 2μM, and fast response time of ~ 3s. The developed biosensor was also used for the urea detection in water samples through spike-recovery experiments, which illustrates satisfactory recoveries. In addition, the obtained desirable selectivity towards specific interfering species, long-term stability, reproducibility, and repeatability further confirm the potency of as-fabricated urea biosensor.